新型三电平PWM交流斩波器

A Novel Three-Level PWM AC Chopper

交流斩波器广泛地应用于工业加热、灯光控制、感应电动机的软起动等领域。随着电力电子技术的不断发展 ,其应用领域不断向高电压、大功率电能变换拓展。在高压电能变换中 ,现有器件的电压等级往往不能满足装置的需要。多电平技术是解决这一问题的常用方法。与此同时 ,多电平电路使用较多的电平数去逼近所希望的波形 ,使输出电压或电流的质量大大提高 ,谐波含量减少。多电平技术在交流斩波器中应用研究尚不多见。介绍了一种新型三电平PWM交流斩波器的电路拓扑。分析了其工作原理以及浮动电容的电压控制原理 ,分析了输出电压的谐波含量 ,最后给出了实验结果和波形。实验结果表明 ,三电平交流斩波器工作原理正确 ,可以正常工作。

With the development of power electronics,the application areas of AC choppers are extending to high voltage and power converting,such as PET.In the high voltage and power converting,the voltage level of power electronics devices sometimes can't satisfy the requirements of equipment.The technology of multilevel is a usual way to solve this problem.Multilevel technology used in AC chopper is scarcely seen. A novel three level PWM AC chopper is proposed.It can achieve high voltage converting by using lower voltage level power electronies device.And at the same time,it utilizes more levels to get output that improves the quality of output waveformThe basic operational theory and voltage balance control method are discussed in the paper.Finally,experiment result is given.The result shows the basic theory of this kind of AC chopper is right and it works well.