基于模块化多电平技术的有源滤波器研究

摘要

Multilevel inverter is usually used in medium voltage high power frequency conversion and reactive power compensation device. Compared with the traditional multilevel inverter, the modular structure is easy to expand to any level, which makes it more flexible and adaptive. Based on the analysis of the configuration and principle of MMC, a active power filter based on modual multilevel converter was proposed, which improved the quality of the voltage graed and waveform. Compatible multilevel hysteresis-space vector for MMC-APF was designed for only a pair of moduals of each pahse was controlled by the mode of PWM. The requirement to reduce the switching frequency of power electronic devices is not satisfied in the conventional capacitor voltage balancing control. To slove this problem, an optimized capacitor voltage balancing control was proposed, which reduced the execution frequency selection mechanism and was used in the part of the modules. The effectiveness and feasibility of the proposed control strategy are verified by the simulation performed based on Matlab.%多电平逆变器通常应用于中压大功率变频和无功补偿装置中。与传统的多电平逆变器相比，其模块化设计易于扩展，灵活性更高，适用范围更加广泛。在分析了MMC的拓扑结构、工作原理的基础上，首先设计了一种采用模块化多电平逆变器（MMC）的有源滤波器（APF），提高电压等级和波形质量。采用适合MMC-APF的多电平滞环空间矢量控制方法，每相中只有一对模块进行PWM调节。针对传统的电容电压平衡控制中子模块投切频繁、器件开关频率较高的缺点，提出了一种电容电压优化控制策略，除了降低选择机制的执行频率外，可将传统的排序选择机制应用于部分模块。 Matlab的仿真结果验证了控制策略的有效性和可行性。