兼具无功补偿功能的模块化多电平整流器控制策略

A Control Strategy of Modular Multilevel Rectifier With Reactive Power Compensation Function

考虑到高压直流输电接入点的电能质量问题,提出了兼具无功补偿功能的模块化多电平整流器(modular multilevel rectifier,MMR)控制策略。在建立三相静止坐标系下MMR的数学模型基础上,提出了电压外环和电流内环的双闭环控制策略。电流内环采用无差拍控制,实现了指令电流快速无差跟踪,改善了系统网侧的电能质量。针对相间环流和子模块电容电压均衡,采用平均电压控制和均衡控制,减小了相间环流。仿真和样机实验结果验证了所提方法的可行性。

Considering the power quality at the grid-connection point of HVDC power transmission system, on the basis of establishing the mathematical model of modular multilevel rectifier （MMR） under three-phase stationary reference frame, an outer voltage-loop and inner current-loop based dual closed-loop control strategy is proposed. The dead-beat control is applied in inner current-loop to implement fast tracking of instruction current with zero steady-state error and improve the power quality at grid side. In allusion to interphase circulating current and capacitance voltage balance of submodules, the average voltage control and balancing control of submodules are adopted. The feasibility of the proposed MMR control strategy is validated by results of both simulation and prototype experiments.