Identification Of Effective Operating Point By Simulation For PD, POD And APOD Switching Schemes Of Various Levels Cascade H Bridge Inverters
In order to achieve higher voltage, input to DC Drives Multi level Inverters(MLI) are adopted. Various Switching
Schemes are available to operate the Drive Circuits with Multilevel Inverters. Due to the increased no of switches and
frequency of switching operation, multilevel inverters are resulting in switching losses, stress on switches. Multilevel
inverters are reducing the level of Total Harmonic Distortion but at the same time its operation is resulting in more switching
losses. To overcome the limitations specific modulation techniques like SPWM, SHEPWM & SVM are implimented.
SHEPWM is comparativly complicated and require high voltage levels. SHEPWM is capable of eliminating only lower order
harmonics. These limitations of multi-level inverters are forcing to depend on filters to address the disadvantages of
In the present paper a thorough analysis of multi-level inverter, with respect to various switching schemes for a given Drive
load is presented. Voltage THD and Current THD for different switching Schemes for a range of Modulation index are
obtained. This analysis will help in identifying the optimum switching scheme and Modulation Index for a given Drive Load.
Which will avoid the dependency on complex control strategies in order to obtain lesser current and voltage Total Harmonic
Index Terms— Multilevel Inverters, Current THD, Voltage THD, PSWM, SHEPWM and SVM. Cascade H Bridge Inverter,