నైరూప్య

THD Analysis of Multilevel Inverter with Different Loads

Siji Chacko, Dr.Jaimol Thomas

Multilevel inverters got a lot of attention in recent years because its ability to generate staircase waveform which is more close to pure sinusoidal waveform. It has lot of applications in industries, FACTS devices, vehicle propulsion etc where power quality is more important. Instead of using higher rating semiconductor devices it uses some combinations of small rating semiconductor devices. It has several advantages such as less THD (Total Harmonic Distortion), reduced Electro Magnetic Interference (EMI), lower switching stresses and increased voltage capability. In this paper reversing voltage type multilevel inverter is modelled and THD analyses with different loads are done. The multilevel inverter used in this paper has two parts; one operated at high frequency (Level generation part) and other operated at line frequency (polarity generation part). The switching loss can be reduced to some extend by the use of polarity generation part. These types of inverters are appropriate choice for all type of loads and resultant THD with each type of loads are analysed. Simulations has been carried out in MATLAB/SIMULINK