Performance Evaluation of Single Phase H - Bridge Type Diode Clamped Five Level Inverter

The Diode Clamped Multilevel Inverter (DCMLI) is an attractive type multilevel inverter due to its robustness. This paper discusses new modulation strategies for a single phase five level H-bridge type DCMLI with reduced components as compared to conventional DCMLI. The chosen multi level inverter is controlled with multicarrier based Sinusoidal Pulse Width Modulation (SPWM) technique with Variable Frequency (VF), Phase Shift (PS), Carrier Overlapping (CO), Phase Opposition and Disposition (POD), Alternative Opposition and Disposition (APOD) and Phase Disposition (PD) PWM techniques. The performance of proposed strategies are evaluated through MATLAB-SIMULINK/POWER SYSTEM BLOCKSET / POWER GUI. The variation of Total Harmonic Distortion (THD), VRMS (fundamental), Form Factor (FF), Crest Factor (CF) and Distortion Factor (DF) are observed for various modulation indices. The simulation results indicates that sinusoidal reference with PODPWM/APODPWM provides output with relatively low distortion. It is also seen that COPWM strategy is found to perform better since it provides relatively higher fundamental RMS output voltage.