L-C Filter Design Implementation and Comparative Study with Various PWM Techniques for DCMLI

 ABSTRACT:

 

In recent time’s multi-level inverters are widely used I industrial application, grid integration, renewable system, buildings and smart grid technology, etc. Uninterruptible power supply has become indispensable to our society. Concern with power quality and grid integration, a pure sinusoidal voltage current waveform is necessary. For such reason a design of various filters is now emerged in research area. Filters have property to smooth current and voltage waveform. This paper proposes filter design guideline for L-C filter with IGBT based multi-level inverter. An L-C circuit used at the inverter output for filtering purposes and ensuring that the THD is lower. The L-C filter cancels all harmonics and a real pure sinusoidal output voltage and current is obtained. Variable voltage and frequency supply to A.C. drives is invariably obtained from a three-phase voltage source inverter. A various pulse width modulation (PWM) schemes are used. The most widely used PWM schemes for three phase voltage source inverters are carrier-based sinusoidal PWM (SPWM) and space vector PWM (SVPWM).

In this paper a method for an asynchronous motor with inverter and L-C output filter is presented and it is verified by simulations in Matlab-Simulink. The simulation results are presented for three-phase five-level diode clamped inverter followed by three-phase L-C filter. The simulation results are compared with sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) for diode clamped multilevel inverter (DCMLI) in terms of THD.

KEYWORDS:

 

1.      DCMLI

2.      SPWM

3.      SVPWM

4.      L-C filter

5.       PWM

6.      THD

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:  

In this paper, the multicarrier SPWM and SVPWM control schemes with phase disposition (PD) is presented for DCMLI. With and without L-C filter the design algorithm of filter is presented here with THD comparison for PWM techniques. With the use of filter, the output voltage is almost sinusoidal in nature. Analysis for THD contents with use of filter on the output side of inverter shows significant improvement in the THD contents compared to the results of without using filter. This shows usefulness of L-C filter for industrial, grid integration and renewable energy applications.

REFERENCES:

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