implementation and design of switched boost …implementation and design of switched boost inverter...

Implementation and Design of Switched Boost

Inverter with PWM control Shreya V. Hule1, Pragati N. Korde2,

Electrical Department, Pune University [email protected]

[email protected]

Abstract— Switched Boost Inverter (SBI) is a single stage power converter derived from Inverse Watkins Johnson topology (IWJ).

Switched boost inverter (SBI) is a single-stage power converter suitable for micro-grid because it can provide ac & dc simultaneously

.The output voltage at the AC terminals of SBI for serving ac loads may be higher or lower than the input dc voltage available from

the PV panel. Switched Boost Inverter is advanced version of Z- source inverter which possess better electromagnetic interference

noise immunity. This paper explains mathematical calculations and detailed operation of SBI is explained theoretically and simulated

using MATLAB /Simulink model.

Keywords— Switched Boost Inverter, Inverse Watkins Johnson topology, Z- source inverter, Matlab.

I. INTRODUCTION

Proposed inverter circuit based on the inverse Watkins–Johnson (IWJ) topology that can achieve similar advantages as that of a ZSI. The systematic development of this inverter topology is described starting from the basic IWJ circuit [1]. Pulse Width Modulation (PWM) control strategy for the Switched Boost Inverter is formulated and implemented using a simple analog circuit[2]. The proposed circuit requires two switches and one pair of an LC filter apart from the VSI [3].

The principle operation of SBI can be used as a power conditioning unit in solar PV interfaced micro grid [4]. Switched boost inverter is applicable for renewable energy sources. Figure 1 shows the basic block diagram of switched boost inverter. Renewable energy source such as solar PV is input of SBI. It boosts dc voltage with PWM control signal. SBI convert DC solar input to AC output.

Fig.1 Block diagram of Switched Boost Inverter with PWM control.

The next section reviews mathematical modelling of PWM control switched Boost Inverter and their modes of operation. Section III is followed by its simulation by pulse width modulation control strategy. Section IV is followed by efficiency of PV cell and their fill factor of solar cell. Simulink Model of switched boost inverter with PWM control application for PV generation is explained in section

II SWITCHED BOOST INVERTER

Switched Boost Inverter have property of shoot-through of the inverter legs. It will take care not to cause any damage to the

converter. AC terminal voltage of SBI is higher or lower than given PV cell input.

A Mathematical Modelling

During Ton period (0 < t < D.Ts)

……….(1)

………(2)

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……….(3)

During Toff period (D.Ts < t < Ts)

………….(4)

………….(5)

………….(6)

Using volt second balance, we have

. …………..(7)

From this equation it is clear that varies with duty cycle. When D=0 ratio is unity and it approaches to 0.5 it become very

high. Thus shoot through duty ratio of SBI cannot exceed 0.5

Fig.2. Circuit diagram of Switched Boost Inverter [2]

B Modes of Operation

Fig 3(a) SBI circuit diagram during positive half cycle (b) During negative half cycle the period (1-D)Ts

Mode 1

To explain the steady-state operation of the SBI, assume that the inverter is in a shoot-through zero state for duration D. TS in a

switching cycle TS. The switch S is also turned on during this interval. As shown in the equivalent circuit of Fig 3.3(a) the

inverter bridge is represented by a short circuit during this interval. The diodes DA and DB are reverse biased (as VC > VG),

and the capacitor C charges the inductor L through switch S and the inverter bridge. The inductor current in this interval equals

the capacitor discharging current.

Mode 2

For the remaining duration of the switching cycle (1 −D). TS, the inverter is in non-shoot-through state, and the switch S is

turned off. The inverter bridge is represented by a current source in this interval as shown in the equivalent circuit of Fig. 3.3(b)

now, the voltage source VG and inductor L together supply power to the inverter and the capacitor through diodes DA and DB.

The inductor current in this interval equals the capacitor charging current added to the inverter input current.



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Note that the inductor current is assumed to be sufficient enough for the continuous conduction of diodes DA and DB for the

entire interval (1 − D). TS.

III SINUSOIDAL PWM TECHNIQUES FOR SBI

Fig 4 Schematic representation of PWM signal [2]

Fig 4 shows reference signal , carrier signal and shoot through signal. By comparing refernce signal and carrier signal obtained,

gate signal for S1and S2 and after that the gating signal for S, S2, S4 are obtained with the use of constant shoot through signal.

The sinusoidal refernce signal having frequency is 50Hz and carrier signal frequency is 10KHz. Here shoot through constant

signal is selected as 0.6 and modulation index is ratio of maximum value of reference signal to maximum value of carrier signal

which is selected as 0.6. Where maximum value of carrier signal is assumed to be 1. Figure 4 shows output waveform of

modified PWM control signals. Fundamental output voltage is given as

…………………(8)

The duty ratio D of boost coverter should be chosen such that it does not disturb power interval.

Fig 5: Simuling waveform of sinusoidal signal, triangular signal and shoot through signl

IV SIMULATION AND EXPERIMENTAL RESULT

A Simulation Result

Simulation of Switched Boost Inverter is done using MATLAB software as shown in fig 6. The parameters used in this

simulation are listed in Table 1



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Table 1: Parameters used in simulation

Parameters Values

temperature 250C

Frequency of carrier signal 10kHz

Frequency of reference signal 50Hz

Input capacitor 470uf

Inductor L 5.6mH

Capacitor C 100uF

Filter Inductor Lf 4.6mH

Capacitor filter Cf 10uF

Fig 6. Schematic of PWM control Switched Boost Inverter

Simulations are carried out by using MATLAB R2018A.Simulations are carried out for an input voltage of 65V. The switching frequency is selected as 10 kHz. Different result is obtained from simulation model is shown below.

Fig 7 Input DC Voltage 65 Volt



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Fig 8 Output DC Voltage 188 Volt

Fig 9 Voltage across inverter bridge

Fig 10 AC output Voltage 65 V

B Prototype of switched boost inverter.

Experimental Setup of Switched Boost Inverter as done on dot board. The photograph of the SBI prototype is shown in Fig. 6.1.

The prototype is explained by dividing the entire setup into three functional blocks. The first is the controller circuit, the second

is the gate driver circuit and the third is the main supply.



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Table 2 Prototype specifications.

Parameters/ Components Attributes Component Specifications

Input voltage (Vg) 15V DC S1, S2, S3, S4 MOSFET IRF 540

Fundamental frequency (f0) 50Hz S IGBT 15N120

Switching Frequency (Fs) 10kHz D1, D2 UF 5408, 4Amp, 250V

Shoot through duty ratio (D) 0.4 Gate Driver IR2110 , TLP250

Modulation Index (M) 0.5 Cf 0.1uF ac 400Vac

Inductor(L) 2.2mH Lf 1.2mH 4Amp

Capacitor (C) 220 uF

Output filter Inductor (Lf) 4.6 mH

Output filter Capacitor (Cf) 1uF

Load resistance (R) 100 ohm

Fig 11 Photo of prototype switched boost inverter

1. Controller Circuit-The 18F4520 is a low-power ,high performance CMOS 8 bit microcontroller. It is a very popular ,

low cost , general purpose microcontroller due to their industry standard instruction set. There are two controller circuit

one is used for high frequency i.e controlling main switch S. The other is used for low frequency control i.e for

controlling other switches S1, S2, S3, S4. 230V Ac supply will be step down to 12V-20V by step down transformer.

B0505 IC provide 5V isolate power supply. This 5 V DC will given as input to 18F4520 microcontroller and other

peripheral circuit such as LCD, LED indicator.

2. Gate driver circuit-Gate driver circuit: 5V pulse from the controller IC will be strengthened using the buffer amplifier

i.e., the current will be increased but the voltage remains the same. The output of the buffer amplifier is 5V dc. The

output of the buffer IC will be given as the input to the opt coupler IC. An opto-isolated gate driver is used in order to

provide isolation between the low power controller circuit and the main SBI circuit.

3. Switched Boost Circuit: SBI circuit: 230V AC is stepped down to 12V AC using a step-down transformer. Output of

the transformer is rectified using diode bridge rectifier and rectified DC voltage is fed as input to the SBI circuit. The

SBI output voltage is measured across the load R. Outputs are obtained using the laboratory prototype of the SBI

shown in Fig. The result of the laboratory prototype is used to verify the theoretical analysis simulation results.



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C Hardware Result

Fig 12 AC output and DC output of Switched Boost Inverter and SPWM

TABLE 3 SIMULATED RESULT AND EXPERIMENTAL RESULT

V CONCLUSIONS

This project is based on the development and analysis of Inverters. A prototype of inverter and converter section is tested and

results are experimentally verified. In Future the topology can be extended to decrease in dead time in SBI in with no shoot

through state.

REFERENCES

[1] S. M. Metev and V. P. Veiko, Laser Assisted Microtechnology, 2nd ed., R. M. Osgood, Jr., Ed. Berlin, Germany: Springer-Verlag, 1998.

[2] J. Breckling, Ed., The Analysis of Directional Time Series: Applications to Wind Speed and Direction, ser. Lecture Notes in Statistics. Berlin, Germany: Springer, 1989, vol. 61.

[3] S. Zhang, C. Zhu, J. K. O. Sin, and P. K. T. Mok, “A novel ultrathin elevated channel low-temperature poly-Si TFT,” IEEE Electron Device Lett., vol. 20,

pp. 569–571, Nov. 1999. [4] M. Wegmuller, J. P. von der Weid, P. Oberson, and N. Gisin, “High resolution fiber distributed measurements with coherent OFDR,” in Proc. ECOC’00,

2000, paper 11.3.4, p. 109.

[5] R. E. Sorace, V. S. Reinhardt, and S. A. Vaughn, “High-speed digital-to-RF converter,” U.S. Patent 5 668 842, Sept. 16, 1997. [6] (2002) The IEEE website. [Online]. Available: http://www.ieee.org/

[7] M. Shell. (2002) IEEEtran homepage on CTAN. [Online]. Available: http://www.ctan.org/tex-archive/macros/latex/contrib/supported/IEEEtran/

[8] FLEXChip Signal Processor (MC68175/D), Motorola, 1996. [9] “PDCA12-70 data sheet,” Opto Speed SA, Mezzovico, Switzerland.

[10] A. Karnik, “Performance of TCP congestion control with rate feedback: TCP/ABR and rate adaptive TCP/IP,” M. Eng. thesis, Indian Institute of Science,

Bangalore, India, Jan. 1999. [11] J. Padhye, V. Firoiu, and D. Towsley, “A stochastic model of TCP Reno congestion avoidance and control,” Univ. of Massachusetts, Amherst, MA,

CMPSCI Tech. Rep. 99-02, 1999.

[12] Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification, IEEE Std. 802.11, 1997.

Parameters Hardware result Simulink result

Input DC voltage 12 Volt 65 Volt

Output DC Voltage 20 Volt 188 Volt

Output AC voltage 10 Volt 65 Volt

Modulation Index 0.5 0.4

Shoot through duty ratio Vary from 0 to 1 0.6



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implementation and design of switched boost …implementation and design of switched boost inverter...

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