power meter design

8/13/2019 Power Meter design

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BACHELOR OF ENGINEERING (Hons)

in ELECTRICAL & ELECTRONICS ENGINEERING 3+0

in collaboration with UNIVERSITY OF BRADFORD UK

INTELLIGENT POWER METER

PENG FEI

Project Supervisor: Ms. Zuraidah bt. Harith

INTI INTERNATIONAL UNIVERSITY

Stage 3 BEng Project

JUNE 2011


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Abstract

Nowadays, people consume electricity everyday. But electricity mostly is produced from

coal which is limited on earth. The huge amount of producing coal causes deep damage on

environment. Some people still does not have the awareness of saving electricity. Besides

this, the common power meter is not able to display the amount of electric bill. Therefore,

this project is designed to help electricity consumer directly understand how much the

electricity cost them. The waste in residence is not only electricity but also the consumers

money.

This project consists of two parts: 60% hardware implementation and 40% software

programming. The main focus of this project is to measure the power consumption from

devices.

The measurement system is designed to measure voltage and current from AC line. Then

the value of them will be stepped down or amplified as the input of PIC microcontroller.

PIC16F877A is used as the control system of this project. With the aid of this

microcontroller, the program can be performed to calculate the real power consumption

simply multiplying two inputs (voltage and current) together from measurement system. And

according to the local tariff, the amount of electric bill will be carried out based on power

consumption during certain time period.

The result from the calculation will be displayed on LCD display module in order to

notice the users how much power they consume and how much it will cost them. After one

month, the power consumption and amount of electric bill will be reset.

This Intelligent Power Meter is successfully built to meet the specifications and aims.

This project provides a great opportunity to improve designerspractical skills on hardware

and software.


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Acknowledgement

I really appreciate University of Bradford to give this precious opportunity to us so that we

have the exposure to practical world.

First of all, I would like to thank Ms. Zuraidah bt. Harith being the greatest supervisor to

provide ideas, give guidance to solve problems on this project and keep monitoring my

progress. Without her assistance, this project would not be working successfully.

Next, I would like take this opportunity to thank INTI International University laboratory

assistances. They tried to give all their helps to us making us feel so comfortable in the

laboratory.

I want to thank my friends especially Vincent Chan, Kim Siong and Chen Zijian for their

kindness and helpfulness. They gave me really constructive suggestions and lend their tools to

me.

Finally, I like to thank my parents are always being supportive and understanding on my

oversea study. I really appreciate what I am doing and being the one of this greatest family

members.


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Declaration

I, Peng Fei, declare that the project is entirely my own work where due references are

made. The project was completed under the supervision of Ms. Zuraidah bt.Harith.

Yours faithfully,

.

Peng Fei

UoB No:08028913

14thJune 2011


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Table of Contents

Chapter 1 Introduction ................................................................................................................... 1

1.1 Project title ........................................................................................................................... 1

1.2 Background .......................................................................................................................... 1

1.3 Project aims and objectives ................................................................................................... 2

1.4 Report outline ....................................................................................................................... 2

1.5 Scenarios of project .............................................................................................................. 4

1.6 Phase of project .................................................................................................................... 4

Chapter 2 Literature Review........................................................................................................... 5

2.1 Introduction .......................................................................................................................... 5

2.2 Power supply system ............................................................................................................ 52.2.1 Transformer ................................................................................................................... 5

2.2.2 Regulator and rectifier ................................................................................................... 6

2.2.2.1 Regulator ................................................................................................................. 6

2.2.2.2 Rectifier ................................................................................................................... 7

2.3 Measurement system ............................................................................................................. 8

2.3.1 Transformer ................................................................................................................... 8

2.3.2Shunt resistor .................................................................................................................. 8

2.3.3 Operational amplifier ................................................................................................... 10

2.3.4 Rectifier ....................................................................................................................... 10

2.4 PIC control system .............................................................................................................. 11

2.4.1 PIC16F877A ................................................................................................................ 11

2.4.2 LCD display module .................................................................................................... 12

2.5 Software ............................................................................................................................. 12

2.5.1 Multisim ...................................................................................................................... 12

2.5.2 MikroC pro .................................................................................................................. 12

2.5.3 Eagle ........................................................................................................................... 12

2.6 Comparison with current power meter project ..................................................................... 13

Chapter 3 Methodology ................................................................................................................ 14

3.1 Hardware overview ............................................................................................................. 14


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3.2 Power supply system .......................................................................................................... 15

3.3 Measurement system ........................................................................................................... 16

3.3.1 Current measurement ................................................................................................... 17

3.3.1.1 Shunt resistor ......................................................................................................... 17

3.3.1.2 Voltage follower ................................ .................................................................... 18

3.3.1.3 Rectifier ................................................................................................................. 19

3.3.2 Voltage measurement .................................................................................................. 19

3.3.2.1 Transformer ........................................................................................................... 19

3.3.2.2 Voltage divider ...................................................................................................... 19


3.3.2.4 Rectifier ................................................................................................................. 20

3.4 PIC control system .............................................................................................................. 20

3.4.1 Hardware ..................................................................................................................... 21

3.4.1.1 PIC microcontroller ............................................................................................... 21

3.4.1.2 LCD display module .............................................................................................. 22

3.4.2 Software ...................................................................................................................... 23

3.4.2.1 Initialization ........................................................................................................... 25

3.4.2.2 ADC conversion .................................................................................................... 26

3.4.2.3 Calculation of power consumption and electric bill ................................................ 273.4.2.4LCD display............................................................................................................ 29

Chapter 4 Results ......................................................................................................................... 31

4.1 Simulation approach ........................................................................................................... 31

4.1.1 Power system ............................................................................................................... 31


4.1.2.1 Shunt resistor ......................................................................................................... 34


4.1.2.2 Rectifier ................................................................................................................. 36

4.1.3 The current measurement of two lamps ........................................................................ 37


4.1.4.1 Workability of measuring voltage in Multisim ....................................................... 39

4.1.4.2 Transformer ........................................................................................................... 40


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4.1.4.3 Voltage divider ...................................................................................................... 41


4.1.4.4 Rectifier ................................................................................................................. 42

4.2 Practical approach ............................................................................................................... 43



4.2.3 Power supply system ................................................................................................... 50

4.3 LCD analog inputs measurement ........................................................................................ 50

4.4 Hardware constructions....................................................................................................... 52

Chapter 5 Discussion.................................................................................................................... 53

5.1 Result discussion ................................................................................................................ 53

5.2 Problems encountered and solutions.................................................................................... 55

5.3 Validity of the project ......................................................................................................... 58

5.4 Limitation of Intelligent Power Meter ................................................................................. 58

Chapter 6 Conclusion ................................................................................................................... 59

6.1 Technical specifications ...................................................................................................... 60

6.2 Future Enhancement ........................................................................................................... 61

References ................................................................................................................................... 62

Appendix A: Gantt chart .............................................................................................................. 66Appendix B: Schematic diagram .................................................................................................. 67

Appendix C: PCB layout .............................................................................................................. 68

Appendix D: Software .................................................................................................................. 69

Appendix E: List of Components ................................................................................................. 75


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List of figures

Figure 1.1 Table of energy loss due to power meter....1

Figure 2.1 Transformer5

Figure 2.2 LM7805 regulator.......6

Figure 2.3 MICW04M bridge rectifier .....7

Figure 2.4 the operation of bridge rectifier7

Figure 2.5 Connection shunt resistor...8

Figure 2.6 5W 10 shunt resistor....9

Figure 2.7 High current rating and low resistance shunt resistor.....9

Figure 2.8 MCP6004 OP-AMP...........10

Figure 2.9 PIC16F877A..11

Figure 2.10 416 characters LCD Module...12

Figure 2.11 Electromechanical meter...13

Figure3.1 Block diagram of Intelligent Power Meter. .14

Figure 3.2 The circuit of power supply system15

Figure3.3 The circuit of measurement system.....16

Figure 3.4 Voltage follower (unity gain differential amplifier) ...18

Figure 3.5 Voltage divider ...19

Figure 3.6 Schematic diagram of PIC control system .....21

Figure 3.7 Schematic of PIC16F877A.22

Figure 3.8 Schematic of LCD display module.....23

Figure 3.9 Flow chart of power meter.....24

Figure 3.10 Configuration of LCD display module .25

Figure 3.11 Initialization of parameters... 25

Figure 3.12 Configuration of input and output ports ...25


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Figure 3.13 Calculation of voltage ......26

Figure 3.14 Calculation of current ...27

Figure 3.15 Calculation of power consumption...27

Figure 3.16 Calculation of electric bill28

Figure 3.17 Calculation of electric bill29

Figure 4.1 Simulation of power supply system...31

Figure 4.2 Waveform of the output from transformer.32

Figure 4.3 Waveform of the output from bridge rectifier32

Figure 4.4 Waveform of the output from LM7805 voltage regulator..33

Figure 4.5 Simulation of measuring current33

Figure 4.6 Waveform of output voltage from shunt resistor...34

Figure 4.7 Waveform of output voltage from voltage follower in current measurement35

Figure 4.8 Waveform of output voltage from rectifier in current measurement.36

Figure 4.9 Simulation of measuring current on two lamps. .37

Figure 4.10 Waveform of voltage across shunt resistor in the simulation with two lamps.38

Figure 4.11 Waveform of output of voltage follower in the simulation with two lamps.38

Figure 4.12 Waveform of output of rectifier in the simulation with two lamps..38

Figure 4.13 Simulation of measuring voltage ..39

Figure 4.14 Workability of measuring voltage in Multisim40

Figure 4.15 Output of transformer...40

Figure 4.16 Voltage across line 10 and line11.41

Figure 4.17 Output voltage of voltage follower on voltage measurement ..42

Figure 4.18 output voltage of rectifier on voltage measurement.42

Figure 4.19 Output of shunt resistor with one lamp43

Figure 4.20 Output of shunt resistor with two lamps ..43


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Figure 4.21 Output of voltage follower with one lamp44

Figure 4.22 Waveform of voltage follower with one lamp .44

Figure 4.23 Output of voltage follower with two lamps44

Figure 4.24 Waveform of voltage follower with two lamps45

Figure 4.25 Output of rectifier with one lam45

Figure 4.26 Waveform of rectifier with one lamp46

Figure 4.27 Output of rectifier with two lamps46

Figure 4.28 Waveform of rectifier with two lamps.46

Figure 4.29 Input of transformer..47

Figure 4.30 Input of transformer..47

Figure 4.31 Output of voltage divider ..47

Figure 4.32 AC output of voltage follower..48

Figure 4.33 DC output of voltage follower..48

Figure 4.34 Waveform of voltage follower.49

Figure 4.35 Output of rectifier.49

Figure 4.36 Waveform of rectifier...49

Figure 4.37 Output of power supply system50

Figure 4.38 LCD display with one lamp..50

Figure 4.39 LCD display with two lamps51

Figure 4.40 ADC module readings..51

Figure 4.41 The display of electric bill52

Figure 4.42 Hardware construction..52

Figure 5.1 Fault in LCD55

Figure 5.2 Program of AAA loop56

Figure 5.3 Readings in current measurement with oscilloscope.57


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Chapter 1

Introduction

1.1 Project title

The final year project is given as Intelligent Power Meter. To achieve this project

successfully, the essential knowledge is required such as display devices, digital electronics,

microcontrollers and programming.

1.2 Background

The targets to measure in this project are light bulbs and a fan. The light bulb is a

resistive device [1]. And the fan is an inductive device. Any inductive device with a coil ofwire like motor will cause the current and voltage are out of phase. It contributes power

factor is less than one. Hence, there will be energy loss in the inductive devices. However,

the consideration of power meter is not necessary in Intelligent Power Meter project. Because

the modern devices such as washing machine and air-conditioner are designed with power

factor correction and power management system to reduce the energy loss due to power

factor. This information can be referred to High-End Solution from Texas Instrument [2] [3].

Besides it, there is a proof that the power factor from inductive home appliances does not

give significant effect on the electricity bill. The further calculation and explanation involved

in this proof is stated in Powerelectronics.com [4].

Figure1.1 Table of energy loss due to power meter [5]


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As Figure1.1 shown above, the energy losses due to power factor for refrigerator,

washing machine, clothes dyer and air conditioner cost less than 20 cent/month. Such low

cost from power factor is negligible.

As the result of two reasons stated above, Intelligent Power Meter will not be considered

to measure and calculate with power factor even though it measures the apparent power.

1.3 Project aims and objectives

The aim of this project is to design and implement an Intelligent Power Meter by

developing the objectives and specifications.

The objectives of this project:

1. Meter should read the power consumed from one or two devices.

2. Meter should consist of total power and monthly power consumed.

3. Based on monthly power consumed. Student must be come up with the amount that needs

to be paid shown on LCD

4. Monthly power reader part can be reset.

1.4 Report outline

Chapter 1 Introduction

In this chapter, the background, specifications, aim of this project are introduced to

readers. This provides the understanding of Intelligent Power Meter that why the project

initiated and how it is going to achieve. With the aid of chapter 1, the reader is easy to

understand the deeper analysis in the following chapters.

Chapter 2: Literature review and theoryChapter 2 will discuss about the difference of current existed power meter and this

Intelligent Power Meter. Besides this, the components are introduced to provide the

justification of the most suitable one. Hence, the selection of components can be done

according to components introduction.


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Chapter 3: Methodology

With the decision of selecting components and the design of power meter, the method to

achieve power meter is explained in detail. It has two major parts: hardware and software. It

focuses on how the circuit functions and the software programming.

Chapter 4: Results

The chapter consists of two approaches to obtain the results which are either from

Multisim simulation approach or practical approach. The results are showing with diagram

and description. The understanding of power meter from users is enhanced with how the

measurement system and PIC control system works.

Chapter 5: Discussion

Discussion will investigate the major problems encountered and the results between

Multisim simulation approach and practical approach. This provides effective explanation to

readers so that they can fully comprehend the operation of power meter.

Chapter 6: Conclusion

The designer will conclude the achievement of this project and comment on the results.

Despite of these, the future enhancement will be discussed.


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1.5 Scenarios of project

The devices will be placed on the 240VAC line. The voltage will be stepped down by the

transformer. The current will be converted into voltage using shunt resistor connected in

series with Neutral line. Both voltage transformer and current shunt resistor have two outputs.

PIC16F877A only understands one ADC input from transformer and shunt resistor.

Therefore, the voltage follower is used to convert two inputs into one output. The voltage

across two inputs is equal to the voltage between the output and ground. The output of

voltage follower is still AC voltage which will not keep constant in PIC16F877A so the

calculation cannot be done.

Next, the rectifier will cap the peak voltage of AC voltage. PIC16F877A will take these

values to calculate the actual voltage and current. The power consumption will be obtained

from the multiplication between voltage and current. Hence, the electric bill will be carried

out.

There are four values showing on LCD display: voltage, current, power consumption and

electric bill. The reason to display current is because there is electric breakdown happened in

residences due overload. The residences can refer to current to adjust how many loads should

work simultaneously.

1.6 Phase of project

Intelligent Power Meter project are categorized into six phases as shown below:

Phase 1: Comprehend the project aim and objectives.

Research the theory of power meter.

Phase 2: Circuit design

Algorithm of measurement system and PIC control system

Phase 3: Circuit test and development of software

Phase 4: Troubleshooting on circuit and software

Phase 5: Design and implementation of PCB board

Phase 6: Test and troubleshooting on PCB board


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Chapter 2

Literature Review

2.1 Introduction

In real life, power meter runs 24 hours continuously to monitor the power consumption of

devices. If it stops working for certain time, this will result in inaccuracy to the electric bill.

Therefore, this project must equip with a power supply which can work continuously without

any failure. The best solution is to convert 240VAC to 5 VDC for PIC control system.

For home appliance AC line, it works with 240VAC and 13A MAX in 50HZ. The aim of

measurement system is to convert 240VAC and 13A MAX into a value in such manner

where it is compatible with PIC microcontroller. In measurement system, there are voltage

measurement and current measurement. The output of measurement system will be processed

to PIC controller.

In PIC control system, the PIC microcontroller must be able to have ADC module,

perform calculation and interface with LCD display module.

2.2 Power supply system

2.2.1 Transformer

Transformer has two coils, primary coil and secondary coil. It uses magnetic field formed

by primary coil to move electrons to secondary coil. Thus, the electricity current is

produced. The secondary voltage is proportional to the primary voltage with the ratio of

Figure 2.1: Transformer [6]


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the number of turns in secondary coil to the number of turns in the primary coil. Theformula of this fact is shown as below:

The 220VAC to 9VAC transformer is selected based on the availability. This transformer

has the largest ratio between primary and secondary in the market. Since 5VDC power

supply is needed in this project. Therefore, the 10V AC to 5VDC converter is required.

2.2.2 Regulator and rectifier

2.2.2.1 Regulator

Voltage regulator can convert AC voltage into DC voltage. There are various outputs

available among the regulator products. The most common one is with starting series number

78 and 79. 78 series are with a positive output and 79 series are with a negative output.

LM7805 is applied into this project. It is able to regulate 10 VDC into 5 VDC. LM7805

is picked is to meet the 10VAC output from transformer.

Figure 2.2 LM7805 regulator [7]


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2.2.2.2 Rectifier

The bridge rectifier MICW04M is applied as shown in Figure 2.3. It has the function to

convert AC input voltage to DC ripple output voltage. And it fully utilizes four diodes in

bridge to perform the full-wave rectification. Full-wave rectification brings the fact that no

matter rectifier circuit is in positive half cycle or negative half cycle, the current will flows inthe same direction through the load.

Figure 2.3 MICW04M bridge rectifier [8]

Figure 2.4 The operation of bridge rectifier [9]


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2.3 Measurement system

2.3.1 Transformer

The operation of transformer in measurement system is the same as the one using in

power supply system. The reason to use two separated transformers with same characteristics

is because of the consideration of safety. If power supply system fails, the independent

measurement system is still able to operate.

2.3.2Shunt resistor

When the device switches on, the current will flow through the device and shunt resistor.

As current appears, voltage will be across shunt resistor. Based on Ohms law, the current

can be obtained by

Where R=10.

5W10Neutral

Line

Current I

Voltage V

The shunt resistor is very crucial for power meter that must be protected from damage.

The fixed cement power resistor is adopted as the shunt resistor.

Figure 2.5 Connection shunt resistor


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2.4 PIC control system

2.4.1 PIC16F877A

PIC16F877A plays the roles as a microcontroller which consists of input/output pins,

ROM, RAM, CPU, Oscillator and A/D converter. The reason to choose microcontroller but

not microprocessor is that the microcontroller has low power consumption, high performance

of computation and low economical price but it is only designed to perform a specific task.

These characteristics are more suitable for hobbyists project like this Intelligent Power

Meter. Microprocessor has powerful CPU which is able to perform multitasking. It is built in

most commercial products.

Comparing to others PIC microcontroller with PIC16F877A, PIC16F877A meets the

requirements of ADC converter, I/O port, EEPRO M and oscillator.

Fi ure 2.9 PIC16F877A 13


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2.4.2 LCD display module

JHD204A LCD Module is involved in this project because it can interface with

PIC16F877A. It has 416 characters. This LCD module shown as below will display the

current, voltage, power consumption and electric bill.

2.5 Software

2.5.1 Multisim

National Instrument MULTISIM is powerful software which provides the platform for

users to achieve simulation of design without taking time to implement the circuit in real life.

The measurement system circuit testimony will be done in Multisim.

2.5.2 MikroC pro

MikroC pro is a C compiler for PIC microcontrollers to design for the development,

building and debugging PIC-based embedded application [15]. Therefore, PIC16F877A can

be compiled using this software.

2.5.3 Eagle

Easily Applicable Graphical Layout Editor is software with the function of schematic

capturing and PCB layout. It can automatically generate PCB layout from schematic. It is

more convenience than Express PCB.

Figure 2.10 416 characters LCD Module [14]


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2.6 Comparison with current power meter project

For the common power meters, they are electromechanical meter which applies two coils

for voltage and current measurement using the effect of magnetic flux. It only displays power

consumption. The residences are confused how much it will cost them. Besides these, the

amount of power consumption is increment. If the residences want to know how much the

power consumption is, they have to take current power consumption to minus with the power

consumption from last month.

Intelligent Power Meter will apply microcontroller to measure the power consumption.

The results will be in digital form which can be accurate as electromechanical meter. This

project can provide more convenience to the residences.

Figure 2.11 Electromechanical meter [16]


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3.2 Power supply system

The circuit design of power supply system from 10VAC to 5VDC is drawn in EAGLE

software as shown below:

GND

10VAC

RectifierRegulator

5VDC

GND

In this project, the operational amplifier MCP6004, PIC16F877A and LCD module

requires 5V power supply. Power supply system steps down 240 VAC to 10VAC using

transformer. Then, it converts 10VAC to 5VDC using rectifier and voltage regulator. And in

order to smooth the ripple voltage, the C1, C2 and C3 are used.

In this project, the 220V input to 9 V output transformers is applied. Hence, the ratio of

number of turns is

The theoretical output from the transformer in this project is

Then, the ratio between transformer and AC power line is

The ratio of LM7805 is . Therefore, the output of LM7805 or the output of

power supply system is

Figure 3.2 The circuit of power supply system


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3.3 Measurement system

In measurement system, there are two parts involved:

1. Voltage measurement: it consists of transformer, voltage divider, voltage follower

and rectifier.

2. Current measurement: it consists of shunt resistor, voltage follower and rectifier.

The following is the circuit of measurement system drawn in EAGLE software.

The output of measurement system will be the input of PIC control system.

GND 5V

Voltage measurement

Current measurement

Voltage divider Voltage

follower

Voltage

follower

Rectifier

Rectifier

Output of

transformer

Output of shunt

resistor

PIC ADC chann

PIC ADC chann

V3

V4

V1

V2

Figure3.3 The circuit of measurement system


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3.3.1 Current measurement

3.3.1.1 Shunt resistor

The wattage rating of shunt resistor is 5w and resistance is 10. According the formula

The maximum current can be obtained as

This current rating is not only for shunt resistor but also for this Intelligent Power Meter

project. Approximately, it can support four 40W lamps at the same time.

There is 240V 40W lamp on AC line. Hence, the current it draws is

According to this, the current of shunt resistor when one lamp works on AC line is also

0.167A. Then, based on Ohms law, the voltage across it is

Then, when two lamps switch on, the voltage across shunt resistor will be

This voltage will be the input of current measurement and voltage follower.


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3.3.1.2 Voltage follower

This voltage follower is constructed with differential amplifier. The voltage output of

differential amplifier is

Where V1 and V2 are marked in Figure 3.3

When

=

=

, this differential amplifier has the unity gain (gain =1). It is called

voltage follower. Then,

Where is RMS voltageThe voltage follower is implemented by the operational amplifier MCP6004.Before

designing the circuit, the safety must be considered as mention in section 2.3.3. There are

two formulas for analog inputs protecting resistors which are squared in Figure 3.3.

In this case, the designer has chosen 17.7Kas protecting resistors.

Figure 3.4 Voltage follower (unity gain differential amplifier) [17]


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3.3.1.3 Rectifier

The rectifier is designed with bridge diode to provide full wave output. The output of

voltage follower will be in AC voltage. However, ADC module of PIC only can read

constant DC voltage. To meet this, the idea of designing rectifier is created. The rectifiertakes the as the output of itself. Then,

3.3.2 Voltage measurement

3.3.2.1 Transformer

The transformer is adopted as the same from power supply system. The output of the

transformer is 9.8VAC as mentioned in section 3.2.

3.3.2.2 Voltage divider

Vd

The ratio of two resistors and is determined the output voltage. After thetransformer, the voltage is too high for the operational amplifier MCP6004. The purpose of

voltage divider design is to step down the voltage. Depending on the resistance of voltage

divider, the designers can get the suitable output voltage in their design. The formula of

voltage divider is shown as below:

Figure 3.5 Voltage divider [18]


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In this voltage divider, the ratio between input voltage and output voltage is 0.09 as

shown below.

Then, the output of the voltage divider will be

Where 9.8V is the output of transformer


The voltage follower in voltage measurement has the same operation as the voltage

follower in current measurement in section 3.3.1.2. The output of voltage follower in voltage

measurement is

Where V3 and V4 are marked in Figure 3.3

3.3.2.4 Rectifier

The rectifier in voltage measurement has the same operation as the rectifier in current

measurement in section 3.3.1.3. The output of rectifier in voltage measurement is

3.4 PIC control system

In Figure 3.6, the PIC control system is presented. It functions to control inputs and

outputs according to the programming. With the aid of LCD display and PIC16F877A, PIC

control system is able to read analog inputs from measurement system and to perform the


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calculation to gain the actual current and voltage. These actual values will be showed on the

LCD display module.

5V

GND

Output of voltage

measurement

Output of current

measurement

3.4.1 Hardware

3.4.1.1 PIC microcontroller

There must be 5VDC power supply to pin 1 (VPP) with 1K resistor, pin 11(Vcc) and pin

21(Vdd). The ground must be provided to pin 12 and pin 31 (Vss/Gnd). Pin 13 and pin 14

(Osc1 and OSc2) needs to connect with 8M crystal oscillator with two 22pF capacitors.

The output of current measurement is connected with pin 2 ADC module (ADCON0).

The output of voltage measurement is connected with pin 3 ADC module (ADCON1). And

pin 33 to pin 38 will be connected with LCD display module.

Figure 3.6 Schematic diagram of PIC control system


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3.4.1.2 LCD display module

The LCD display module is adopted to display the current, voltage, power consumption

and electric bill. As shown below, it is the list of LCD display module connection.

LCD Pins PIC port B pins

Pin1 Ground

Pin2 5V

Pin3 Ground with 1K resistor

Pin4 Pin 37 RB4

Pin5 Ground

Pin6 Pin 38 RB5

Pin7 Null

Pin8 Null

Pin9 Null

Pin10 Null

Pin11 Pin 33 RB0

Pin12 Pin 34 RB1

Pin13 Pin 35 RB2

Pin14 Pin 36 RB3

Pin15 5V

Pin16 Ground

Figure 3.7 Schematic of PIC16F877A


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5V

Ground

PIC16F877F

3.4.2 Software

The flow chart of the whole process to measure power consumption is presented as

following Figure 3.9. It is processed in PIC control system using C language. This software

programming is written with the configuration hardware input and output pins. There are 3

major parts in this program:

1. Voltage reading2. Current reading3. Power consumption and electric bill calculation

Figure 3.8 Schematic of LCD display module


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Start

Initialization

Is curret reading

larger than last

reading?

Case:AAA

No

Yes

Calculate and

display actual

voltage

Read from analog

input channel 1

No

Yes

Calculate and

display actual

current

Read from analog

input channel 0

Calculate and

display power

consumption P=VI

Calculate electric

bill

Is curret reading

larger than last

reading?

After 1 hour,

electric bill

increment

After 1 month,

power meter reset.

Voltage

reading

Current

reading

Power

consumption

and electric bill

Figure 3.9 Flow chart of power meter


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3.4.2.1 Initialization

Figure 3.10 shown above is the configuration of LCD display module. The pins of LCD

are connected according to the list of LCD display module connection.

Figure 3.11 shown above is the initialization of parameters which are going to be used in

the program.

Unsigned char has 8 bits size and the range from 0 to 255. Unsigned long has 32 bits

and range from 0 to 4294967295 which are sufficient for calculation and readings. Unsigned

int has 16 bits and range from 0 to 65535.

Figure 3.10 Configuration of LCD display module

Figure 3.11 Initialization of parameters

Figure 3.12 Confi uration of in ut and out ut orts


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Figure 3.12 shown above is the configuration of input and output ports. RA0, RA1 and

RA2 in Port A are configured as inputs. All pins in Port B are outputs. Besides these, the

LCD display module is initialed.

3.4.2.2 ADC conversion

ADC conversion is to convert analogue voltage input into digital form which is

understood by microcontroller. The output of measurement system is read by ADC module in

PIC16F877A. This ADC module has 10 bits with 1024 sampling levels to represent the ADC

inputs. 1024 sampling levels have 0 to 1023 resolutions.

In ADC module, the voltage reference is 5V by default in PIC16F877A. Hence, one

resolution represents 0.0048V,

Figure 3.13 above shows the actual voltage calculation. The output of voltage

measurement will be read by Channel 1 in ADC module of PIC16F877A. The output of

voltage measurement is 0.568 (obtained in 4.1 voltage measurement). And the input of

voltage measurement is 244V. Then, the ratio between them is

Figure 3.13 Calculation of voltage


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Because the operation in MikroC pro does not accept decimal, 429.57 is represented by

42957/100.

Figure 3.14 shows the actual current calculation. The output of current measurement will

be read by Channel 0 in ADC module. And it is 1.788 (obtained in 4.2 current measurement).

And the input of voltage measurement is 1.67V (mentioned in 3.3.1.1 Shunt resistor). Then,

the ratio between them is

1.07 can be represented by 100/107.

3.4.2.3 Calculation of power consumption and electric bill

To get power consumption is to simply multiply voltage with current as Figure 3.15. u

and i isthe output from voltage and current calculation.

The home user in Malaysia is charged by domestic tariff from Tenaga Nasional Berhad.

The domestic tariff is RM0.218/KWH which is represented by[19]. To obtain how much

the power consumption costs the home appliances users is to multiply power consumption

with RM0.218/KWH in each hour. For the demonstrate purpose, the one hour time is

represented by 1 second (1000ms).

Figure 3.14 Calculation of current

Figure 3.15 Calculation of power consumption


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C1< 9

a=power0.218RM/kwh

Display amount ofelectric bill

m=a+b

Voltage, current,power consumption

calculation

Initializationb=0

Case:AAA

C1=C1+1

b=m

Reset

Delay 1 second

As to the calculation of electric bill, in the initialization, b=0. The program goes through

the voltage, current, power consumption calculation. At the beginning of electric bill

Figure 3.16 Calculation of electric bill


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program, the 10 loops are set with parameter C1. C1 increments from 0 to 9. Since there is 1

second delay, the 10 loops will be defined as 10 second.

The 10 loops command checks whether the current loop is bigger or equal to 9. If it is, it

will proceed to reset all the parameters and goes back to case: AAA. If it is less than 9 times,

the program will perform calculation and following command lines.

When the loop is less than 9 times, the calculated amount of money is put in a. Then,

the total amount m equals to a + b. The sum of a + b is displayed on LCD. C1 increments

by the step of 1.

Next, the m will be stored in b. After 1second, the program will go back to case: AAA.

Therefore, by following this method, the amount of money can increment with 1 second and

all parameters can be reset when 10 loops reached.

For the demonstration purpose, one hour is represented by 1 second. And 720 hours

(30days24hours=1 month in hours) are represented by 10 seconds.

3.4.2.4LCD display

For display of voltage, current and power consumption, they are 5 digits. The decimal

point is between the third digit and the fourth digit. For electric money, it needs 6 digits.

Figure 3.17 Calculation of electric bill


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Figure 3.17 shown above is the 5 digits display program. To obtain the individual digit is

to make the parameter (i or v) divide by . X is the number of digits. For example, thedesigner wants to extract 5 digits with decimal between the third digit and the fourth digit.

Then, it will

Extracting 4 digits, 3 digits and 2 digits etc. follows the above algorithm as shown in

Figure 3.17.


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Chapter 4

Results

This chapter provides the practical evidence of each system in this project. There are two

approaches to verify the operation of power meter. The first is simulation approach on

Multisim and another is practical approach from constructed circuits.

4.1 Simulation approach

4.1.1 Power system

The following is the simulation of power supply system.

As the result shown in Figure 4.1, the output from the power supply system in simulation

is 4.99V.

In order to observe the whole process of AC to DC conversion, at first, the operation of

transformer is investigated.

`

Figure 4.1 Simulation of power supply system


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Figure 4.2 is showing that of the transformer output is 11.173V.And .

The bridge rectifier is the next process after transformer. It rectifies the 11.173VAC into

9.57VDC as shown in Figure 4.3 so that voltage regulator is able to accept this as an input.

LM7805 voltage regulator has the ability to step down 10VDC input to 5VDC output. As

shown in Figure 4.4, the output of LM7805 voltage regulator is 5.001VDC. This will supply

to all the systems. Then,

Figure 4.2 Waveform of the output from transformer

Figure 4.3 Waveform of the output from bridge rectifier


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The simulation of measuring current in Multisim is done as shown below in Figure 4.5.

The result is obtained as the following. In this simulation, since Multisim does not support

the AC power line with Life, Neutral and Earth, the single line AC power source is applied

instead. Based on the theory of AC power line, the negative part of this AC power source can

be seen as Neutral line and the positive part of it can be seen as Life line.

Figure 4.4 Waveform of the output from LM7805 voltage regulator

Figure 4.5Simulation of measuring current


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In the simulation, the output voltage of voltage follower in current measurement is

0.09VAC shown in Figure 4.5 XMM3. The ratio between voltage followerand shunt resistor is

There is difference between simulation and theory on the output voltage of voltage

follower in current measurement is because the output of voltage follower also connects to

the bridge rectifier where is the voltage cancelling certain voltage from 0.165VAC to obtain

0.09VAC.

The waveform of output voltage from voltage follower in current measurement is

investigated in oscilloscope as shown in the following. It has the same butonly with half cycle because the operational amplifier MCP6004 is not able to accept

negative input.

The output of voltage follower proves that it successfully change two inputs into an

output with same value. Therefore,

The ratio of Vpeak between voltage follower and shunt resistor with one lamp is

Figure 4.7 Waveform of output voltage from voltage follower in current measurement


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4.1.2.2 Rectifier

The minimum output of rectifier is 175.614nV and the maximum output of rectifier is

176.716nV.

There is still a small ripple voltage existing in output after smoothing capacitor 220uF C4.But, this output becomes DC voltage in the PIC analog input manner.

Figure 4.8 Waveform of output voltage from rectifier in current measurement


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4.1.3 The current measurement of two lamps

This is the testimony for more than one device on the AC power line to observe the

difference with the simulation with one device. The two exactly same lamps are added in this

simulation.

From the readings shown in Figure 4.9, the voltage across shunt resistor, , , andoutput of voltage follower all are doubled comparing the readings in the simulation with one

lamp shown in Figure 4.5. This shows that the voltage across the shunt resistor is proportion

to the drawing current from devices. More devices operates at the same time, more current

will be drawn. Then, higher voltage across shunt resistor presents.

The voltage across shunt resistor in the simulation with two lamps is measured as the

following Figure 4.10. The ratio between this voltage and 0.234V from section 4.1.2.1Shunt resistor is

Figure 4.9 Simulation of measuring current on two lamps


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The output of voltage follower is obtained from Figure 4.10 as following with the same

from Figure 4.11. And it becomes half cycle due to the negative input limitation ofMCP6004.

The output of rectifier in Figure 4.12 is obtained with slight increase from 175.614nV to

179.77nV comparing to Figure 4.8.

Figure 4.10 Waveform of voltage across shunt resistor in the simulation with two lamps

Figure 4.11 Waveform of output of voltage follower in the simulation with two lamps

Figure 4.12 Waveform of output of rectifier in the simulation with two lamps


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As shown below Figure 4.14, the outputs from the same circuit with different sources and

lamps are different. The circuit with 240V lamp has much lower voltage output. But the

circuit with 120V 100W lamp can get the expected output 5V. This states Multisim does not

have the ability to simulation with 240V Lamp. However, it is still able to simulation with

output. The results from the simulation 240V lamp have the value to make the comparison

with practical results. This method is workable.

4.1.4.2 Transformer

Figure 4.14 Workability of measuring voltage in Multisim

Figure 4.15 Workability of measuring voltage in Multisim


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The output from transformer is obtained as above in Figure 4.15. is 0.904V.Then, . is 1.818V. This output will be the input forvoltage divider. It is supposed to be the same as the transformer in power supply system. Due

to the workability mentioned in section 4.1.4.1, the transformer is failed in Multisim.

The ratio between transformer and AC power line is

4.1.4.3 Voltage divider

In the waveform Figure 4.16, it is obtained by oscilloscope across line 10 and line 11.

The is 82.265mV. Then,

And the output from transformer in Figure 4.15 is 904.853mV.The ratio between voltage divider and transformer is

The output voltage across transformer will undergo the operation of voltage divider to getthe output across line 10 and line 11

Figure 4.16 Voltage across line 8 and line10


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The output of this voltage follower is 90.031uV. Then, Because of Multisim standard as discussed in 3.3.2.1 Workability of measuring voltage

in Multisim, 240V lamp does not work properly in this voltage measurement. it brings the

fault that 5VDC power supply is not generated. Hence, the Op Amp MCP6004 does not turn

on. The functionality of voltage follower is not performing in this case.

The ratio between voltage follower and voltage divider is 4.1.4.4 Rectifier

Figure 4.17 Output voltage of voltage follower on voltage

Figure 4.18 Output voltage of rectifier on voltage measurement


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The output of this rectifier in Figure 4.18 is 391.615nV. Then, without proper inputfrom voltage follower, the result has fault also. But the waveform is still rectified into DC

voltage.

4.2 Practical approach


The output of shunt resistor with one lamp shown in Figure 4.19 is 1.696VAC. This is the

actual current one lamp draws.

The output of shunt resistor with two lamps shown in Figure 4.20 is 3.355VAC. This is

the actual current the lamp draws. It is the double of the current with one lamp in shunt

resistor.

Figure 4.19 Output of shunt resistor with one lamp

Figure 4.20 Output of shunt resistor with two lamps


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The output of voltage follower with one lamp shown in Figure 4.21 is 0.983VAC. The

ratio between voltage follower and shunt resistor is . The waveform of voltage

follower with one lamp is shown in Figure 4.22 which has Vrms 1.27VAC

Figure 4.21 Output of voltage follower with one lamp

Figure 4.23Output of voltage follower with two lamps

Figure 4.22 Waveform of voltage follower with one lamp


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The output of voltage follower with two lamps in Figure 4.23 is 1.717VAC. It is the

double of the current with one lamp in voltage follower. The ratio between voltage follower and shunt resistor is

.

Comparing Figure 4.21 and Figure 4.23, the Vamp ( ) of waveform in voltagefollower with two lamps is about double of the Vamp ( ) of waveform in voltagefollower with one lamp.

The output of rectifier with one lamp in Figure 4.25 is 1.788VDC. The ratio between

rectifier and voltage follower is.

Figure 4.25 Output of rectifier with one lamp

Figure 4.24 Waveform of voltage follower with two lamps


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The output of voltage follower with two lamps as shown in Figure 4.27 is 3.175VDC. It

is the double of the current with one lamp in voltage follower. . In the waveformof rectifier with two lamps in Figure 4.28, its amplitude is 3.24VDC.

Figure 4.27 Output of rectifier with two lamp

Figure 4.26 Waveform of rectifier with one lamp

Figure 4.28 Waveform of rectifier with two lamps


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The output of voltage divider is 0.870VAC as shown above in Figure 4.31. Then, the

ratio between voltage divider and transformer is

The AC output of voltage follower is 0.456VAC as shown above in Figure 4.32. Then,

the ratio between voltage follower and voltage divider is .

The DC output voltage is 0.563V in Figure 4.33 and the waveform showing the Vrms

output of voltage follower is 0.472V in Figure 4.34. It has the 0.02V difference with Vrms

measured in multimeter in Figure 4.33

Figure 4.32 AC output of voltage follower

Figure 4.33 DC output of voltage follower


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The DC output of rectifier is 0.568V as shown above in Figure 4.35. Then, the ratio

between rectifier and voltage follower is . The waveform of rectifier shown inFigure 4.36 has the amplitude 0.560mV with ripple voltage.

Figure 4.35 Output of rectifier

Figure 4.34 Waveform of voltage follower

Figure 4.36 Waveform of rectifier


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4.2.3 Power supply system

The Figure shown above in Figure 4.37 is the output of power supply system from

voltage regulator. The output voltage is 0.496VDC

4.3 LCD analog inputs measurement

The result of LCD display is obtained as above in Figure 4.38. With one lamp

working, the current showing is 0.16V and the voltage is 244.14. The power

consumption is 39.06W . The electric bill is below powerconsumption with increment with 1 second time.

Figure 4.38 LCD display with one lamp

Figure 4.37 Output of power supply syestem


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With two lamps working, the current showing in Figure 4.39 is 0.31V and the voltage is

244.14. The power consumption is 75.68W

. It shows that with more

devices adding the voltage stays at 244.14V.

The resolution read from channel 0 for current measurement is 360. To convert it to

voltage is shown in Figure 3.13 Calculation of voltage. The result of this conversion is the

output of voltage measurement from rectifier shown in Figure 4.40.

VThe resolution read from channel 1 for current measurement is 111. To convert it to

voltage is shown in Figure 3.14 Calculation of current. The result of this conversion is the

output of current measurement from rectifier shown in Figure 4.40.

V

Figure 4.39 LCD display with two lamps

Figure 4.40 ADC module readings


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At this moment in Figure 4.41, the power consumption is 37.26W. According to the tariff

0.218RM/KWH, 37.26W will cost the user .As shown in Figure 4.41, the amount of electric bill is exactly displayed on LCD

4.4 Hardware constructions

Power plug

to devices Power plug

from wall outlet

TransformerShunt

resistor

Power supply

system

Voltage

follower

Rectifier

Voltage divider

PIC control

system with

LCD

Measurement

system

As shown in Figure 4.42, the hardware of power supply system, measurement system and

PIC control system are constructed on PCB board.

Figure 4.41 The display of electric bill

Figure 4.42 Hardware construction


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Chapter 5

Discussion

5.1 Result discussion

Systems Parts Theory

(output)

Simulation

approach(output)

Practical approach(output)

Power supply

system

Regulator 4.9VDC 5.001VDC 4.98VDC

Current

measurement

Shunt resistor 1.69VAC 1.65VACRatio

0.545

1.696VAC

Ratio

0.579

Voltage follower 0.9VAC(M)1.65VAC(O)

0.983VAC(M)

1.27VAC(O)Rectifier 0.175uVDC 1.788VDC

Voltage

measurement

Transformer 9.8VAC 0.639VAC Ratio to

58mV is

0.09

10.3VAC Ratio to

0.87V is

0.0834

Voltage divider 0.882VC 58mVAC Ratio

0.001

0.87VAC Ratio

0.534Voltage follower

63.6uVAC 0.456VAC(M)

0.47VAC(O)

Rectifier 91.615nVDC 0.568VDC(M)0.560VDC(o)

The results obtained from three approaches: theory in Chapter 3 Methodology, simulation

approach and practical approach in Chapter 4 Results. The capital O beside the values states

that the value taken from waveform in oscilloscope. The capital M beside the values states

that the value taken from multimeter.

In power supply system, the output 4.9VDC in theory is proven with 5.001VDC in

simulation approach and 4.98VDC in practical approach.

Table 1 Results


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In current measurement, the outputs of shunt resistor and voltage follower are obtained

with only 2.7% errors.

.

But for rectifier, there are very large errors. It is because in the database of Multisim it is

lack of bridge rectifier. The only type of bridge rectifier is applied in Multisim which is not

the one in practical approach. Therefore, with different components, the result definitely will

be different.

In voltage measurement, due to the workability of measuring voltage in Multisim, the

results are not reliable. But the operating evidence still can be found in the ratio between two

components. The ratio between voltage divider and transformer in simulation approach is0.09. And the ratio between them in practical approach is 0.0824. It proves that transformer

and voltage divider are operating.


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5.2 Problems encountered and solutions

Problem 1: the value from measurement system keeps jumping when it shows in LCD display

module.

Reason: The first design of this power meter is without the consideration of rectifier. The output

of measurement system is AC voltage. The ADC module in PIC 16F877F is to converting DC

voltage into a resolution by the method of sampling.

Solution: The rectifier is added in order to convert AC voltage into DC voltage. With the aid of

rectifier, the output of itself is still not the perfect DC voltage but is the ripple voltage as mention

in section 4.1.2.2 and section 4.1.4.5.

Problem 2: the LCD display module does not show the characters but showing the blocks on the

1stand third row.

Reason: the program compiled inside LCD display module is tested in other project which is

workable. And the hardware is synchronized with LCD pins. The only reason will be PIC

hardware connection with faults.

Solution: the fault is found in PIC hardware connection where the MCLR pin1 is connected to

GND with 1k resistor. the correct way is to connect MCLR pin1 to 5 V with 1k resistor.

Figure 5.1 Fault in LCD


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Problem 3: even though the ripple DC voltage is obtained in measurement system, the LCD

display output according to the ripple DC voltage is not stable still having different values in

short period.

Reason: if ripple DC voltage is zoomed in, it is AC voltage with very low peak to peak voltage.

Hence, PIC ADC module will read the voltage along with sinusoidal of ripple DC voltage.

Solution: there is correction in program. The correction is to put the case AAA in front of the

program and check the new reading (vol) whether is larger than last reading (t1). If new reading

(vol) is larger thanthe last reading (t1), the program proceeds to calculation and display actual values. If

new reading (vol) is smaller than the last reading (t1), the program goes back case: AAA.

Problem 4: there is short circuit caused during the wave measurement in oscilloscope. Theoscilloscope is not able to measure the waveform across transformer and input of voltage

follower.

Reason: in order to implement the wave measurement, there is current generated from

oscilloscope. Therefore, any floating point without ground is not the target of oscilloscope. One

of the two probes must connect to GND being reference point.

Solution: the floating point can be monitor in Multisim using oscilloscope. In practical, the

output waveform with common reference point GND can be measured in oscilloscope.

Figure 5.2 Program of AAA loop


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Problem 5: During measuring output of voltage follower in the current measurement, the results

change when the oscilloscope is attached. As shown below Figure 5.2, the current is not zero

when no lamps are on. It shows 1.22A from the current measurement which is not expected.

Reason: as mention in problem 4, the oscilloscope generates current to measure waveform.

Solution: there is no solution for this problem since the reason is from the characteristic of

oscilloscope.

Problem 6: The output voltage from current measurement is not accurate. With one lamp

working, the voltage is 2.1V and with two lamps working the voltage is 2.7 V. they are in the

relation of double values.

Reason: the capacitor adopted at first is 220uF which is small for discharging and charging.

Solution: the designer replaced 220uF with 470uF. The output voltage with two lamps is double

of the output voltage with one lamp.

Figure 5.3 Readings in current measurement with oscilloscope


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5.3 Validity of the project

The components of this project are common in the market. The important component in

Intelligent Power Meter is shunt resistor. If the design acquires large current measurement,

the shunt resistor must equip with the high power consumption rating and low resistance.

With low rating shunt resistor, the maximum current of Intelligent Power Meter is only 0.7A.

The power meter is able to measure current and voltage, perform calculation of power

consumption and electric bill. The amount of money is able to increment in each one hour.

Finally, after one month, PIC16F877A can reset.

5.4 Limitation of Intelligent Power Meter

The project is successfully achieved. But there are few limitations due to the hardware

and software.

1. The Intelligent Power Meter cannot work with high current above 0.7A in theory.2. The time counting for one hour and one month is not accurate on PIC16F877A3. The operational amplifier MCP6004 in voltage follower is easily damaged.


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Chapter 6

Conclusion

The process of introduction, designing, implement and constructing is obtained in the

previous chapter to achieve the project of Intelligent Power Meter. The innovation of

Intelligent Power Meter is the convenience of user. The intelligent part of this project is able

to calculate power consumption and electric bill so that the users will not lost the track of

how much the power consumption cost to them.

The current is represented by voltage using a shunt resistor. The voltage follower is to

change the output of shunt resistor with floating point to the voltage output of voltage

follower with reference point GND. Because PIC inputs can only be with reference point but

not floating point. The rectifier is to convert AC voltage into DC ripple voltage. Then, PIC

16F877A can be stable to calculate. The output of current measurement shows that it is

proportional to the current in the AC power line.

The voltage is stepped down by transformer and voltage divider in order to compatible

with op-amp MCP6004. The function of voltage follower and rectifier has the same

functionality with current measurement. As chapter 4 results shown, the voltage output is not

affected by adding more devices in AC power line.

In conclusion, this project, Intelligent Power Meter is successfully completed based on

the results. The aims and objectives are fully achieved.


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6.1 Technical specifications

No. Technical specification Status and Explanation

1 To construct a circuit which is able to

measure voltage and current

The shunt resistor, voltage follower and

rectifier are constructed in the current

measurement design. Status: achieved.

The transformer, voltage divider, voltage

follower and rectifier are constructed in

voltage measurement design. Status:

achieved.

2 The Intelligent Power Meter is able to

calculate power consumption and electric

bills

According to the output from voltage and

current measurement system, the

PIC16F877 reads the outputs of them and

calculate with the outputs.

The electric bill increments with Malaysia

tariff in every one hour. Status: achieved.

3 The Intelligent Power Meter is able to

display power consumption and electric

bills

The PIC control system consists of

PIC16F877A and LCD display module.

They are interface to display the power

consumption and electric bill according to

the output from measurement system.

Status: achieved.

4 Intelligent Power Meter can monthly reset This specification is achieved in

programming by adding a loop to check the

time is meeting one month. Status:achieved.


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6.2 Future Enhancement

The table as shown below is providing the future enhancement for others designer refers to.

No. Future enhancement Explanation

1 Design wireless transmission and

database.

In each month, the power meter is able to transmit the

data (power consumption and electric bills

) to the database so that it cuts down the cost of

workforce so that the whole system does not need

workers to go every users home to check the power

consumption.

2 Built more robust power meter Short circuit in home appliances is common. If the

robust power meter is designed, it prevents any

damage from short circuit.

Also in order to suit with high load home appliances

users, the shunt resistor must with high rating.

3 Improve the accuracy of power

meter

To meet the accuracy requirement, the designer can

apply current precise sensing amplifier instead of

voltage follower and rectifier. And shunt resistor with

low resistance must be considered in this case.


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References

Web address

1. Basic electronic conceptAvailable from: http://sci301.uvi.edu/Electrical/ElectricalConcepts.htmlLast accessed: 20th October 2010

2. HVAC solution from Texas InstrumentsAvailable from: http://focus.ti.com/docs/solution/folders/print/399.html

Last accessed: 20th October 2010

3. Washing machine: highend solutions from Texas InstrumentsAvailable from: http://focus.ti.com/docs/solution/folders/print/397.html

Last accessed: 20th October 2010

4. MCP6004 datasheetAvailable from: http://ww1.microchip.com/downloads/en/DeviceDoc/21733j.pdf

Last accessed: 7th January 2011

5. Figure1.1 Table of energy loss due to power meterAvailable from:

http://powerelectronics.com/power_management/motor_power_management/705PET23.

pdf


6. Figure 2.1: TransformerAvailable from: http://best-b2b.com/userimg/545/570-1/power-transformer-628.jpg


7. Figure 2.2 LM7805 regulatorAvailable from: http://www.fairchildsemi.com/ds/LM/LM7805.pdf


8. Figure 2.3 MICW04M bridge rectifierAvailable from:http://www.binbin.net/photos/dc-components/wo2/wo2-1.5a-200v-

bridge-rectifier-rc.jpg

http://www.binbin.net/photos/dc-components/wo2/wo2-1.5a-200v-bridge-rectifier-rc.jpghttp://www.binbin.net/photos/dc-components/wo2/wo2-1.5a-200v-bridge-rectifier-rc.jpghttp://www.binbin.net/photos/dc-components/wo2/wo2-1.5a-200v-bridge-rectifier-rc.jpghttp://www.binbin.net/photos/dc-components/wo2/wo2-1.5a-200v-bridge-rectifier-rc.jpg


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9. Figure 2.4 the operation of bridge rectifierAvailable from:

http://www.osha.gov/SLTC/etools/electric_power/illustrated_glossary/substation_equipm

ent/rectifiers.html


10.Figure 2.6 5W 10 shunt resistorAvailable from:

http://www.quickerbuy.com/assets/photo/avatar/51486/big__brtyucwbmk___kgrhqmh-

ceeunsbq1q_blzi6srnn____35.jpg


11.Figure 2.7 High current rating and low resistance shunt resistorAvailable from: http://www.rc-electronics-usa.com/current-shunt.html


12.Figure 2.8 MCP6004 OP-AMPAvailable from:http://ww1.microchip.com/downloads/en/DeviceDoc/21733j.pdf


13.Figure 2.9 PIC16F877AAvailable from:http://ww1.microchip.com/downloads/en/devicedoc/39582b.pdf


14.Figure 2.10 416 characters LCD ModuleAvailable from:

http://www.egochina.net.cn/eshop/ebay/Character/JHD762/P1090306.jpg)


15.MikroC PRO for PICAvailable from: http://www.mikroe.com/eng/products/view/7/mikroc-pro-for-pic/

Last accessed: 23rd January 2011

16.Figure 2.11 Electromechanical meterAvailable from:

http://img.diytrade.com/cdimg/214476/1494287/0/1218724437/Single_Phase_Long_Life

_Round_Power_Meter.jpg)

http://www.osha.gov/SLTC/etools/electric_power/illustrated_glossary/substation_equipment/rectifiers.htmlhttp://www.osha.gov/SLTC/etools/electric_power/illustrated_glossary/substation_equipment/rectifiers.htmlhttp://www.quickerbuy.com/assets/photo/avatar/51486/big__brtyucwbmk___kgrhqmh-ceeunsbq1q_blzi6srnn____35.jpghttp://www.quickerbuy.com/assets/photo/avatar/51486/big__brtyucwbmk___kgrhqmh-ceeunsbq1q_blzi6srnn____35.jpghttp://ww1.microchip.com/downloads/en/DeviceDoc/21733j.pdfhttp://ww1.microchip.com/downloads/en/devicedoc/39582b.pdfhttp://www.egochina.net.cn/eshop/ebay/Character/JHD762/P1090306.jpghttp://img.diytrade.com/cdimg/214476/1494287/0/1218724437/Single_Phase_Long_Life_Round_Power_Meter.jpghttp://img.diytrade.com/cdimg/214476/1494287/0/1218724437/Single_Phase_Long_Life_Round_Power_Meter.jpghttp://img.diytrade.com/cdimg/214476/1494287/0/1218724437/Single_Phase_Long_Life_Round_Power_Meter.jpghttp://img.diytrade.com/cdimg/214476/1494287/0/1218724437/Single_Phase_Long_Life_Round_Power_Meter.jpghttp://www.egochina.net.cn/eshop/ebay/Character/JHD762/P1090306.jpghttp://ww1.microchip.com/downloads/en/devicedoc/39582b.pdfhttp://ww1.microchip.com/downloads/en/DeviceDoc/21733j.pdfhttp://www.quickerbuy.com/assets/photo/avatar/51486/big__brtyucwbmk___kgrhqmh-ceeunsbq1q_blzi6srnn____35.jpghttp://www.quickerbuy.com/assets/photo/avatar/51486/big__brtyucwbmk___kgrhqmh-ceeunsbq1q_blzi6srnn____35.jpghttp://www.osha.gov/SLTC/etools/electric_power/illustrated_glossary/substation_equipment/rectifiers.htmlhttp://www.osha.gov/SLTC/etools/electric_power/illustrated_glossary/substation_equipment/rectifiers.html


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Page 64

17.Figure 3.4 Voltage follower (unity gain differential amplifier)Available from: http://www.electronics-tutorials.ws/opamp/opamp_5.html


18.Figure 3.5 Voltage dividerAvailable fromhttp://www.ehobbycorner.com/pages/tut_resistors.html


19.Tariff RatesAvailable from: http://www.tnb.com.my/tnb/residential/pricing-and-tariff/tariff-rates.html

Last Accessed: 2nd February
http://www.ehobbycorner.com/pages/tut_resistors.htmlhttp://www.ehobbycorner.com/pages/tut_resistors.html


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Page 65

APPENDICES


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Page 66

Appendix A: Gantt chart

The Gantt chart shows as below Table 2

Table 2. Gantt chart

Projected

Actual

Task3 4 5 6 7 8 9 1

011

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

Brainstorming

and planning

Research and

information

collection

First meeting

withsupervisor

Marketsearching forcomponents

Circuit Design

Developingsubsystemcircuit

Programming

Testing and

troubleshooting

Integratingsubsystems

Calibration

Project ReportWriting

Week


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Page 67

Appendix B: Schematic diagram

1. Measurement system and power supply system

2. PIC control system


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Page 68

Appendix C: PCB layout

1. Measurement system and power supply system

2. PIC control system


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Page 69

Appendix D: Software

sbit LCD_RS at RB4_bit;

sbit LCD_EN at RB5_bit;

sbit LCD_D4 at RB0_bit;sbit LCD_D5 at RB1_bit;

sbit LCD_D6 at RB2_bit;

sbit LCD_D7 at RB3_bit;

sbit LCD_RS_Direction at TRISB4_bit;

sbit LCD_EN_Direction at TRISB5_bit;

sbit LCD_D4_Direction at TRISB0_bit;




unsigned char ch;

unsigned long u,i,power,m;

unsigned int vol,t1=0,cur,t2,a,b=0,c1 = 0;

void main()

{

TRISA=0x03; //portA RA0 RA1 RA2 are inputs

PORTA=0x00;

PORTB=0x00; //portB is ouput

TRISB=0x00;

INTCON = 0;

Lcd_Init(); //initial LCD connected to PORTB

LCD_Cmd(_LCD_CLEAR); //clear display

LCD_Cmd(_LCD_CURSOR_OFF); //turn cursor off

while(1){

AAA:


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Page 70

// VOLTAGE

vol=ADC_read(1); // get voltage output of voltage measurement system from ADC

channel 1

if(vol>=t1){

t1=vol;

u=(long)t1*5/1023; // covert adc resolution to voltage

u=u*(42957)/100; //calculate actual voltage

ch=u/10000 ; // extract 100.00V digit

if (ch==0)

{

LCD_Chr(2,2, 32); // write empty space if digit is 0

}else

{

LCD_Chr(2,2,48+ch); // write ASCii + CH at 2nd row, 2nd column

}

ch=(u/1000)%10; // extract 10.00 V

LCD_Chr_CP(48+ch);

ch=(u/100) %10; // extract 01.00 V

LCD_Chr_CP(48+ch); // write ASCii + CH at cursor pointLCD_Chr_CP('.'); // write '.' at cursor point

ch=(u/10) %10; // extract 00.10 V digit

LCD_Chr_CP(48+ch); // write ASCii + CH at cursor point

ch=u %10; // extract 00.01 U digit


LCD_Chr_CP('V'); // write 'V' at cursor point

LCD_Chr_CP(32);

LCD_Chr_CP(32);

LCD_Chr_CP(32);

LCD_Chr_CP('P');

LCD_Chr_CP('D');

LCD_Chr_CP('o');


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Page 71

LCD_Chr_CP('g');

}

else if (vol=t2){

t2=cur;

i=(long)t2*5/1023; //covert adc resolution to voltage

i=i*100/107 ; //calclate actual current

ch=i/10000 ; // extract 100.00A digit

if (ch==0)

{


}

else

{

LCD_Chr(1,2,48+ch); // write ASCii + CH at 1st row, 2nd column

}

ch=(i/1000)%10; // extract 10.00 A digit

LCD_Chr_CP(48+ch); // write ASCii + CH at 1st row, 2nd column

ch=(i/100) %10; // extract 01.00 A digit


LCD_Chr_CP('.'); // write '.' at cursor point

ch=(i/10) %10; // extract 00.10 A digit


ch=i %10; // extract 00.01 A digit


LCD_Chr_CP('A'); // write 'A' at cursor point


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Page 72

LCD_Chr_CP(32);

LCD_Chr_CP(32);

LCD_Chr_CP('W');

LCD_Chr_CP('a');

LCD_Chr_CP('t');

LCD_Chr_CP('t');

LCD_Chr_CP('s');

LCD_Chr_CP('U');

LCD_Chr_CP('P');

}

else if (Cur


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LCD_Chr_CP('W'); // write 'W' at cursor point

//MONEY

if( c1 < 9){ //check whether it reaches 10 second

a=power*218/(1000*1000);

m=a+b;

ch=m/1000000 ;

if (ch==0)

{


}

else

{

LCD_Chr(4,2,48+ch); // write ASCii + CH at 4st row, 2nd column}

ch=(m/100000)%10; // extract 10.00 RM

LCD_Chr_CP(48+ch); // write ASCii + CH at 4st row, 2nd column

ch=(m/10000) %10; // extract 01.00 RM


ch=(m/1000) %10; // extract 00.10 RMLCD_Chr_CP(48+ch); // write ASCii + CH at cursor point

LCD_Chr_CP('.'); // write '.' at cursor point

ch=(m/100) %10; // extract 01.00 RM


ch=(m/10) %10; // extract 00.10 RM


ch=m %10;

// extract 00.01 RM


LCD_Chr_CP('R'); // write 'R' at cursor point

LCD_Chr_CP('m'); // write 'M' at cursor point


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c1 = c1 + 1;

b=m;

delay_ms(1000);}

else if( c1 >= 9){ // if it reaches 10 second reset all parameters

u = 0;

i =0;

power=0;

m=0;

b=0;

a=0;

vol=0;

ch=0;

c1=0;t1=0;

cur=0;

t2=0;

}

goto AAA;

}

}


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Appendix E: List of Components

The components list is shown as below table 3:

Components Price per unit (RM) Units(s) Price (RM)

Terminal block 1.00 10 10.00

Voltage Regulator 1.00 1 1.00

Tact switch 0.40 1 0.40

Diode 0.10 4 0.40

Capacitors 0.50 3 1.50

Rectifier 1.00 2 2.00

Transformer 6.00 2 12.00

16x4 LCD display 36.00 1 19.00

PIC16F877A 17.50 1 17.50

8M Crystal oscillator 1.50 1 1.50

Op amp MCP6004 6.00 2 12.00

IC Socket 0.5 2 1.00

PCB Optic Fibre boards 33.00 1 33.00

Connectors (jumper wire) 0.1 100 10.00

Lamps 2.00 5 10,00

Single phase wire 2.00 5 10.00

Plug 1.00 2 2.00

Power plug extension 10.00 1 10.00

Grand total RM153.3

power meter design

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