模块化多电平换流器的控制和调试方法的研究

Research on the Control and Modulation Methods of Modular Multilevel Converter

模块化多电平换流器是一项用于各类型高电压大功率应用的换流器技术且极具有前景。它表层电路虽较为简单,但可通过不同方式实现换流器的内部动态要求和满足子模块电容电压平衡对系统的高要求。为了阐明这点,以及为今后研究提供指导,提出了4种不同的控制方式和调制方法。研究的是基于降低10kVA换流器的实验,该换流器的每一相都有10个子模块。主要内容是研究子模块电压以及环路电流的动态变化。实验现象表明开环控制方式可得到最快电压响应,其平衡方式是基于采用排序算法,且相较于每个子模块使用专用的电压控制器,该方法更快更简单。

Modular multilevel converter, designed for various types of high voltage and high power applications, has a promising future. Its surface circuit is relatively simple, but it can meet the internal dynamic requirements for the converter and fulfill the high requirements of the sub - modules capacitor volt- age balance for the system in different ways. To illustrate this point and provide directions for future re- search, this paper proposed four different control modes and modulation methods. The research, with the main content focusing on the dynamic change of the sub - module voltage and the loop current, was con- ducted on the basis of the experiment, in which the converter was lowered to IOkVA with ten sub modules in each phase arm. It showed in the experiment that the fastest voltage response could be obtained with the open loop control mode. Compared with the method that each sub- module uses a dedicated voltage con- troller, this sorting algorithm for balance is much faster and more convenient.