Comparative Study Of SPWM And SVPWM Cascaded H-bridge Multilevel Inverter

Large electric drives and utility applications require modern power electronics converter like cascaded H-bridge multilevel inverter (CHB) with separated DC sources is clearly the most practical topology for use as a power converter for medium & high power applications due to their modularization and extensibility. The H-bridge inverter eliminates the large number of bulky transformers, clamping diodes and flying capacitors. Cascaded multilevel inverter (MLI) is contemplated to be suitable for medium & high power applications. There are many pulse-width modulation (PWM) techniques developed for controlling multilevel inverter, among these, SVM is the most popular one due to its simplicity both in hardware and software. But the SVM becomes very difficult to achieve when the levels increases. To simplify the SVM at high level, several improved methods have been proposed in many literatures. In this report, SPWM and SVPWM controlled cascaded H-bridge multilevel inverter for large motor drives is designed, analysed and compared with conventional inverter, by simulating in MATLAB simulink software.