49电平模块化多电平换流器样机设计与实验验证

Design and Experiment of Modular Multilevel Converter Prototype With 49-level Output Voltages

模块化多电平换流器(modular multilevel converter,MMC)具有大量子模块,难以组织和控制,尤其是控制器需要处理大量具有高吞吐能力的IO通道,控制系统复杂度和成本均大为增加,并需要解决多控制器协调运行等问题。设计并实现49电平MMC实验样机。其中,子模块和控制器间采用光纤隔离测控复用电路降低光纤通道数,降低了控制器处理难度和成本;控制器间采用双总线结构进行通讯连接,既保证了控制系统的实时性和可靠性,又满足了大量数据在控制器间传输的要求。通过并网实验对其可行性进行验证,实验结果表明,系统输出波形畸变率低,功率响应迅速且跟踪准确。

There is a large number of submodules in modular multilevel converters （MMC）, but it is difficult to control or even organize these submodules. They are connected with multiple controllers through a great quantity of high-throughput IOs which make the complexity and costs of MMC much high. A prototype of MMC with 49-level output voltages is designed and implemented. Measurement and control signal multiplexers are applied to reduce the number of optical fiber channels. Controllers are connected through a double-bus structure to meet the speed requirement of real-time control signals and the capacity requirement of non-real-time data. Experimental results show the THD of output waveforms is low, the power step respond is quick, and the power tracking is accurate. The results verify the feasibility of the proposed strategy.