电网电压不平衡情况下双馈风力发电变流器控制

Control of doubly-fed wind power generation converter under unbalanced grid voltage

针对电网电压三相不平衡情况下双馈风力发电系统输出功率二倍频谐波分量带来的安全稳定问题,提出了一种以消除二倍频谐波分量为控制目标的正负序双闭环电流控制策略.建立了双馈风力发电系统网侧变流器不平衡条件下的数学模型,进而分析了二倍频谐波分量产生的机理,采用四分之一周期延时方法对正负序分量进行分离,且正负序电流单独参与运算控制来抵消功率二倍频分量.在Matlab/Simulink软件上建立了仿真系统,仿真结果表明了理论分析的正确性和提出控制策略的有效性.

Aiming at the safety and stability problems caused by the double frequency harmonic components of output power of doubly-fed wind power generation system under the unbalanced three-phase grid voltage condition,a positive and negative sequence double closed loop current control strategy,where the control target is to eliminate the double frequency harmonic components,was proposed. The mathematical model for the grid-side converter of doubly-fed wind power generation system under unbalanced condition was established,and the generation mechanism of double frequency harmonic components was analyzed. In addition,the positive and negative sequence components were separated with the 1/4 cycle delay method,and the positive and negative sequence currents were separately involved in the operation control to counteract the double frequency power components. Moreover,the simulation system was established with the Matlab/Simulink software. The simulated results verify the correctness of theoretical analysis and the effectiveness of proposed control strategy.