MMC子模块电容电压改进控制方法的研究

介绍了模块化多电平换流器电容电压测量及均压原理,指出传统的电容电压控制下,当桥臂子模块数目过于庞大时,电压传输信号较多,增加了控制器设计难度。针对这一问题,提出了一种改进的电容电压测量方法,该方法中参与控制的电压信号数量仅为传统测量方法的一半,有利于降低控制系统的设计难度,减轻控制器工作负担。首先详细介绍了电容电压改进控制方法下的模块拓扑结构和电压测量原理,然后在此基础上,设计了改进电容电压排序算法,减少传统排序过程中不必要的运算量,在数据处理过程中进一步优化控制器运算,保证换流器稳定运行。最后搭建了仿真模型,验证所提策略的正确性和有效性。

Research on improved balance control for sub-module capacitor voltage of modular multilevel converter (MMC)

The capacitance voltage measurement and the principle of voltage balance of the modular multilevel con?verter are introduced in this paper. Under the control of traditional capacitor voltage, there are more voltage sensors and more data acquisition results, which increase the difficulty of controller design when the bridge arm includes too many modules. To solve this problem, an improved capacitance voltage measurement method is proposed, and the voltage sensor in every sub module is connected in parallel to the double module output terminals. Capacitance volt?age measurements are performed based on module signals, and voltage sensor number is only half of the traditional measurement method, so as to reduce the cost of the investment and controller workload from the data source. On above mentioned basis, a new capacitor voltage sorting algorithm is designed, which can reduce the amount of un?necessary operation in the traditional sorting process, and further optimize the controller operation in the process of data processing, that ensures the stable operation of the converter. Finally, a simulation model is built to verify the effectiveness of the proposed strategy.