Analysis, Comparison & Simulation of Three Phase 9 Level Cascaded Multilevel Inverter with Advanced Modulation Control Techniques using Less Switches

The multilevel converter is capable of achieving higher power by using a series of power switches with several low voltage DC sources to perform power conversion by synthesizing a staircase voltage waveform. In the field of power electronics the multilevel inverter permits to reach higher voltages with low harmonics content. Rise in the number of levels, the harmonic level of output voltage will fall gradually. In this paper a three phase 9 level cascaded multilevel inverter is been simulated with minimum switching devices and gate circuitry. The classical three phase MLI utilizes 48 switches whereas the minimum circuit utilizes 33 switches thus eliminating 15 switches in the usage. The output is been verified by extracting gate signals from various control techniques like SPWM POD, Harmonic Injected, Trapezoidal & Triangular Modulation. The analysis and comparison is done with THD, and least THD is been found with triangular modulation with the help of MATLAB/SIMULINK tool.