energy efficiency in manufacturing malta. department of industrial electrical power conversion...

ENERGY EFFICIENCYENERGY EFFICIENCYIN MANUFACTURINGIN MANUFACTURING

MALTA

Department of Industrial Electrical Power ConversionFaculty of Engineering – University of Malta

Energy Efficient Electric Motor Energy Efficient Electric Motor Systems for the Systems for the

Manufacturing IndustryManufacturing Industry

Key Experts: Prof. Ing. C. Spiteri-

Staines

Co-Supervisors: Dr. Cedric Caruana

Researcher: Mr. Peter Spiteri

Industrial Partners : Playmobil

Toly Products

Andrews Feeds

Department of Industrial Electrical Power Conversion, University of Malta

IntroductionIntroduction

• It is estimated that motor driven systems account for around 65% of the electricity consumed by the European industry.

• 1.5% improvement in the motors’ efficiency implies a reduction of 1% energy consumption in the European industry.

• The more efficient use of energy in the manufacturing industry has become a key factor for the industrial organisations to maintain a competitive edge.


Aims of ProjectAims of Project

• The objective is to facilitate the adoption of energy saving measures on electric motors by the Maltese industry.

• Carry out an extensive Data gathering exercise on Energy Usage and Patterns of Electrical Motor Systems in various local industries

• The project will deliver a tool which will allow organisations to evaluate alternative options of reducing their electric motors’ energy consumption.

• Benefits derived from project:– Knowledge on energy savings mechanisms for manufacturing

industry– Additional benefits: reduced heat dissipation and lower

maintenance costs.


Increasing Efficiency in Motor Increasing Efficiency in Motor SystemsSystems


IE Motor Efficiency IE Motor Efficiency StandardsStandards

The new standard introduces also IE4 (super premium efficiency), a future level above IE3, but IE4 products are not yet commercially available.

6

50Hz Motors


Comparing Old & New Efficiency Comparing Old & New Efficiency StandardsStandards

• Old Standards EFF1, EFF2 and EFF 3

• New Standards: IE1 – Standard Efficiency (comparable to EFF2)IE2 – High Efficiency (comparable to EFF1)

IE3 – Premium Efficiency


How to minimise losses in Motor How to minimise losses in Motor Driven SystemsDriven Systems

• Replace Old Motor by HEM

• Use a Motor Energy Controller (only certain applications as we will see)

• Use a Variable Speed Drive (inverter)

Study carried out by South Carolina Energy Office


Check Load Profile of MachineCheck Load Profile of Machine

• Low Load means Low Efficiency and Low Power Factor

Try to use a motor close to its rated power, do not overrate without scope!!!


Load Profile of IMMs (w/o accumulator)Load Profile of IMMs (w/o accumulator)

10


Motor Systems Selected for StudyMotor Systems Selected for Study

IMM typeMotor rating (kW)

No. of hrs / yr (ave.)

Accum. ColourClamping

Force (kN)

K 60/S 3C 30 4002 Yes 3-colour 600

K 60/S 2C 22 4247 Yes 2-colour 600

K 60-256/S 2C 30 N/A Yes 2-colour* 600

BA 1500 22 6000 No 1-colour 1500

BA 2000 30 6000 No 1-colour 2000

Motor applicationMotor rating (kW)

Quantity

Mixer 30 1

Conveyer 4 31

Elevator 7.5 11

Cuber 55, 75, 90 8

The study consisted of:• Injection Mould

Machines and• other motor driven

systems such as elevators, conveyers, mixers and cubers,

at partner premises.


Load profile of Load profile of IMM with AccumulatorIMM with Accumulator

Base load

≈ 7.5kW (25%)

Motor rating= 30kW

Average load = 12.2kW

(40.7%)

Max load= 62.7kW

(209%)

Typical load profile of K 60/S 3CK 60/S 3C (with accumulator)


Load profile of Load profile of IMM w/o AccumulatorIMM w/o Accumulator

Base load

≈ 3.2kW(14.5%)

Motor rating = 22kW

Average load = 8.1kW (36.8%)

Typical load profile of BA 1500BA 1500 (no accumulator)

Max load= 43.9kW(199.5%)


Analysis of InjeAnalysis of Injecction Mould Machinestion Mould Machines

• (Summary)

TypeMotor

rating (kW)Base load (kW)

Average load (kW)

Max load (kW)Cons. (kWh / hour)

Average p.f.

K 60/S 3C 30 7.5 (25%) 12.4 (41.3%) 74.2 (247.3%) 12.1 0.54

K 60/S 2C 22 3.5 (15.9%) 8.1 (36.8%) 31.9 (145.0%) 8.1 0.49

K 60-256/S 2C 30 7 (23.3%) 10.0 (33.3%) 70.3 (234.3%) 10.0 0.50

BA 1500 22 3.2 (14.5%) 9.9 (45.0%) 43.9 (199.5%) 9.5 0.991)

BA 2000 30 4.7 (15.7%) 15.9 (53.0%) 62.8 (209.3%) 15.3 0.851)

14

Table showing the motor ratings, typical base loads, average loads, consumption, power factor and peak maximum of all the types. The values in the brackets are the

percentages of the motor ratings

(1) The IMM motor was power factor corrected )


AnalysisAnalysis –– K 60/S 3CK 60/S 3C

Mot

or ra

ting

= 30

kW

26.3%

Mainly due to base load

Electric’s motor percentage time vs the power level


AnalysisAnalysis – K 60/S 3C– K 60/S 3C

16

Mot

or ra

ting

= 30

kW

46.1% Mainly due to base load

Energy consumption vs the power level


Analysis Analysis – BA 1500– BA 1500

Mot

or ra

ting

= 22

kW

14.7% 63.7%


Mainly due to holding pressure

Electric’s motor percentage time vs the power level


Analysis Analysis – BA – BA 15150000

Mot

or ra

ting

= 22

kW

22%

41%


Mainly due to holding pressure

Energy consumption vs the power level


Analysis – Main MixerAnalysis – Main Mixer

Motor at low load = 4.2kW (14%)

Motor rating= 30kW

Motor on load= 18.5kW (61.7%)

Average load= 14.2kW (47.3%)

Mot

or

ratin

g =

30kW

at low load

at high load

13.4% 60.2%

at low load at high

load

68.1%

8.0%

Mot

or

ratin

g =

30kW


Analysis – ConveyerAnalysis – Conveyer

Motor rating = 4kW

Motor at no load ≈ 1.2kW (30%)

Average load = 1.6kW (40%)

low load 67.5%

high load 32.5%

low load 14.1kWhhigh load 15.8kWh


Simulated and Experimental Simulated and Experimental determination of Energy Savingsdetermination of Energy Savings

• Measurements have shown that in many cases, motors are operated for long duration at low load, thus inefficiently.

• Solutions:– Replace motor with HEM– Lower voltage during low load– Use MEC (effectively lowers voltage)– Use VVVF drive (not always possible)

• Tests shall be simulated & tested on an experimental set-up


Simulation of Low Load with Simulation of Low Load with decrease in Voltagedecrease in Voltage

• Analysis of Motor with constant Low Load: Simulation results with supply voltage

reduced from 100% to 45% with a load factor of 25%. The motor rating is 37kW

• The efficiency is increased by 16.8%.

• The input power is decreased from 14.2kW to 11.1kW yielding energy savings of

21.8%.

• If the supply voltage is reduced ONLY during the base load operation, for IMM, the

overall potential energy savings become 9.4%.

% Voltage Pin (kW) Pout (kW) Eff (%) rpmrpm

changePower factor

100 14.2 9.3 65.3 1495 - 0.6129

75 12.4 9.2 74.4 1491 0.27 0.7613

45 11.1 9.1 82.1 1473 1.47 0.9098


Analysis of Lower Voltage Concept Analysis of Lower Voltage Concept to Motor Readingsto Motor Readings

Machine Load factor (%)Base load only

energy savings (%)Overall potential

energy savings (%)

K 60/S 3C 25 20.7 8.8

K 60/S 2C 16 30.0 8.1

K 60-256/S 2C 25 20.7 11.7

BA 1500 15 31.1 5.3

BA 2000 16 30.0 3.5

Machine Load factor (%)Low load only

energy savings (%)Overall potential

energy savings (%)

Elevator 16 29.0 12.1

Cuber 83 - 3.6

Main mixer14 34.8

7.562 7.0

Conveyer 30 15.8 7.5


Transient Response of MEC (Lab Rig)Transient Response of MEC (Lab Rig)

• One of the main challenges is due to the relatively short times at which the motor

operates at the base loads.

– occurences of operation at base load are a lot however the timings are very critical.

– MEC needs to react rapidly to regulate the supply voltage on the motor according to

operation.

0 1 2 3 4 5 6 7 8 9 100

100

200

300

400

500

600

Time (sec)

Input pow

er

(W)

The variation in active power with MEC (OFF to ON)

MEC switched ON


Further WorkFurther Work

• Emulation of Actual Load Profiles on Laboratory Test Rig.

• Verification of Energy Saving Mechanisms (HEM and MEC) on industrial premises

• Development of Motor Energy Saving Tool (MEST).– Software tool to guide organisations’ personnel

(possibly non-technical) to improve efficiency in motor driven systems

Department of Industrial Electrical Power ConversionFaculty of Engineering – University of Malta

Increasing Energy Efficiency Increasing Energy Efficiency during Reliability Testing of during Reliability Testing of

EquipmentEquipmentthrough Grid‐connected Load through Grid‐connected Load

UnitsUnitsKey Experts: Dr. Maurice Apap

Co-Supervisors: Prof. C. Spiteri Staines & Prof. J. Cilia

Researchers: Mr. Francarl Galea

Industrial Partners : Abertax

Delta (Malta)


IntroductionIntroduction

• Manufacturing Cycle

• Testing of each product must take place before reaching the market and the

customer.

• Testing of certain products leads to high energy consumption.

• power supply full load burn-in test usually last for a minimum of 24

hours. (can exceed 400,000kWhr yearly.)

• batteries testing is carried out by cycling.


AimsAims

• This project is targeted at increasing the efficiency during testing of

manufactured electrical equipment: namely, DC Power Supplies and

Battery Banks.

• Currently Electrical Energy consumed

during testing is ‘wasted’ (as heat) in

Active Loads.

• The aim of this project is to REDIRECT

the Electrical Energy used during testing

back to the Electrical Supply.

• 70% energy saving is predicted.


System DescriptionSystem Description

• The Regenerative Active Load

shall be made up of:

• DC-DC Converter Design.

• Grid Connected Inverter.

• The Regenerative Active Load

was designed to operate over a

wide input range of Voltages and

Currents to support different types

of DC Supply Equipment.

Input Voltage 30 – 300V

Max Input Current 25A

Max Input Power 1000W

Output Voltage 200V

Max Output Current <5A

Max Output Power <1000W

Switching Freq. 75kHz

DC/DC Converter Specs

DUT

H.F.DC to DCConverter

MainsSupply

Grid Connected

Inverter


DC/DC Converter TopologyDC/DC Converter Topology

• Out of many topologies studied, the isolated Ćuk topology was selected on the following criteria:

• Low input and output current ripples• can ‘step up’ & ‘step down’ the input voltage• Bipolar current flowing into the transformer (full utilisation)• Saturation of the transformer is not possible• Total isolation of input from output• Transformer’s turns’ ratio can be used to set duty cycle range.

D

DNVV ino

1


Simulation of ConverterSimulation of Converter

Vin =30V Vin =300V


Converter Components Design Converter Components Design

Magnetic Components

Gate Drivers

Power Semiconductors

Analogue Control CircuitSnubbers

ProtectionCircuit


System TestingSystem Testing

The built DC-DC converter was tested and the following issues were checked:

• Components were monitored for overheating

• Monitoring of voltage overshoots during switching transients (to verify

operation within the maximum device ratings).

• Verification that current and voltage ripples were within design limits

• Operation over expected RANGE of output voltage and output current

for the designed input voltage range

• Efficiency was measured for various operating conditions


Regeneration of Electrical EnergyRegeneration of Electrical Energy

• For REDIRECTION of testing

energy to the Mains supply:

• The DC-DC converter was

interfaced to a standard off-the-

shelf Grid-connected Inverter

• The DUT was tested for various

operating points (input voltage and

power) and the energy used was

transferred via the DC-DC, into the

grid-connected inverter, and back

to the mains supply.

DUT

H.F.DC to DCConverter

MainsSupply

Grid Connected

Inverter


Results - Measurement of EfficiencyResults - Measurement of Efficiency

35


Results – Burn-In Test (800W, 200V Results – Burn-In Test (800W, 200V Power Supply)Power Supply)

• Experimental tests show that 78% less energy was used to burn-in test SM400AR-4

(4.9kWh instead of 20kWh in 24 hours).

36

• The overall Active Load

system operates at an

efficiency of 85%.

• Efficiencies of the DC-

DC converter & grid-

inverter were 95% and

89% respectively.


ConclusionsConclusions

• The results show that:– The Regenerative

Active Load unit has the potential of saving electrical energy used in testing in Industry.

– The overall efficiency of the Regenerative Active Load unit ranged from 77% to 85% when operating at full power.

Device under

test (DC Supplies)

Power consumed with resistive bank

Power consumed with Regenerative Active Load Unit

Percentage Savings

SM400-AR-4 (200V)

842W 195W 76.8%

SM70-AR-24 (70V)

928W 245W 73.6%

SM70-AR-24 (35V)

964W 342W 64.5%

ER030-10 367W 127W 65.4%

Es030-5 174W 64W 63.2%

Device under

test (Battery Banks)

Power consumed with resistive bank at C20

Power consumed with Regenerative Active Load Unit (estimate)

Percentage Savings (estimate)

72V 100Ah C20 Battery Bank

360W 68W 81%


Further WorkFurther Work

Input Voltage 30V – 600V

Max Input Current 50A

Max Input Power 2000W

Output Voltage 400V

• To operate system with a wider range of electrical DC supply

equipment, modular converters will have to be employed.

• This shall require that modular converters be connected in

parallel or in series depending on the input voltage requirements.

• Simulation showed successful

parallel and series operation.

• A method of interleaved

switching will be applied to

obtain a further reduction in the

current ripple.


Thank you for your attentionThank you for your attention

MALTA

energy efficiency in manufacturing malta. department of industrial electrical power conversion...

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