三相四线级联DSTATCOM高性能控制新策略

摘要

针对三相四线级联DSTATCOM三相输出电流彼此独立的特点,建立了DSTATCOM的单相模型和基于数字PI的闭环传递函数,提出了一种基于重复控制的单相控制组合的控制策略.该控制策略能够将传统PI控制系统闭环传递函数的相位滞后从56°降低到5°以内(1 kHz处),从而可以改善对谐波和无功的补偿效果.在Matlab/Simulink环境下,建立10 Mvar/10 kV 19电平的级联三相四线DSTATCOM系统仿真模型,通过仿真验证了新控制策略的正确性和可行性.同时,在三相不平衡负载情况下的仿真结果表明,新控制策略比传统的基于三相dq变换的控制策略有更好的补偿效果,而且具有分相补偿能力.%With the consideration that the output currents of three-phase four-wire cascade DSTATCOM (Distribution STATic synchronous COMpensator) are independent,its single-phase model and close-loop transfer function are established based on digital PI and a control strategy including three single-phase controllers is proposed based on repetitive control. Compared with the traditional PI control,the proposed strategy decreases the system phase lag from 56。 to 5。(at 1 kHz),significantly improving the reactive power and harmonics compensation effect. Simulation model of 10 Mvar/10 kV 19-level three-phase four -wire cascaded DSTATCOM is established under Matlab/Simulink environment. Simulative results verify the validity of theoretical analysis. Under the condition of unbalance three-phase load,the proposed control strategy,with the phase-splitting compensation ability,has better performance than the traditional one based on dq transformation.