Voltage harmonic analysis of the inverter with high voltage and large capacity

At present, there are two kinds of the high voltage and large capacity inverter, namely multilevel and multi-pulse inverters. In this paper, multi-pulse inverters are classified into two types according to the interphase transformer configuration. At first, the fundamental and harmonic voltage amplitude expressions of two types of the multi-pulse inverter are proposed and used to analyze the relationship between the output voltage THD (total harmonic distortion) and pulse control parameters of the inverter. Then, the voltage harmonic characteristics of multi-pulse inverters are compared using Matlab/Simulnk. Both analytical and simulation results show that the optimum pulse control parameters can be founded to minimize the voltage THD of the multi-pulse inverter, and the type one of multi-pulse inverters is superior to the other in the harmonic performance. In particular, multi-pulse three-level inverters are more suitable for the power electronic circuit with the high voltage and large capacity because they can not only keep low voltage THD but also utilize semiconductor switching devices with low voltage rating and the interphase transformer with small dimension to obtain the required voltage and power rating.