二极管箝位式多电平逆变器PWM控制技术分析

高压多电平逆变器是高压变频技术领域中发展的一个新分支,本文基于对五电平逆变器控制分析,介绍了二极管箝位式多电平逆变器的单脉冲控制、基于载波的SPWM控制和一种用于五电平逆变器的复式(混合式)控制,并在国外中压交流异步电动机上进行了仿真分析,给出了相应结果。

Analysis of PWM Control Technology for Diode-clamping Multi-level Inverter

High voltage multi-level inverter is a new branch of high voltage VVVF technology area.The Multi-level inverter can get high voltage and great capacity output with low voltage device and without dynamic voltage distribution circuit and transformers.The increase of the number of output voltage can ameliorate the waveform of output voltage,enhances the anti-EMI level and reduce the impact of motor common-mode voltage.On the basis of analyzing of Diode NPC (neural point clamped) five-level inverter,the article presents single pulse control which is often used in a great capacity situation in order to reduce the switch waste, and puts forward two types of SPWM control based on carrier,and proposes a mixed method control for five-level inverter,which is based on making the space voltage vector graph of five-level inverter be equivalent to two space voltage vector graphs of three-level inverter.The article makes a simulation in media-voltage induction machine as well, and gives its results.Based on the simulation result, five-level inverter can decrease the output harmonics remarkably so as to be very propitious to the motors and can enhance the performance of motors.The study on fiver-level inverter in this article has preferable practical value.