Solar PV fed Three Phase Cascaded H Bridge Multi-level Inverter

This paper focusses on three phase Cascaded H bridge Multi-level Inverter (MLI) topology fed by solar Photovoltaic (PV) module. For maintaining maximum power as well as constant voltage for MLI, Perturb and Observe (P&O) technique is applied. Sine Pulse Width Modulation (SPWM) is implemented along with unipolar and bipolar switching scheme. Performance parameters like Total Harmonic Distortion (THD), switching loss, switching stress, Root Mean Square (RMS) fundamental voltage and efficiency of MLI output voltage is calculated and graphically compared for both unipolar as well as bipolar schemes. It is found that unipolar scheme outperforms bipolar scheme in all parameters and hence is better than the later. The control algorithm is also validated in Hardware-in-the-Loop using Typhoon HIL 402 emulator and results are presented and discussed.