LCL滤波的双馈式风电网侧变流器在不平衡电网电压条件下的控制策略

为了提高LCL滤波的双馈式风电网侧变流器在电网电压不平衡情况下的工作性能,通过对变流器在上述条件下的数学模型进行理论分析,提出了基于LCL滤波器的不平衡电流指令算法,并提出了在同步旋转dq坐标系下采用PI和重复控制器并联结构的电流复合控制方案.利用所提控制策略,可有效降低电网电流中的低次谐波含量,实现正负序电流的无差跟...

Control strategy of grid-side converter with LCL filter in doubly-fed wind power system under unbalanced grid voltage

The mathematical model of grid-side converter with LCL filter is built and analyzed to improve its performance in doubly-fed wind power system under unbalanced grid voltage conditions.An unbalanced grid current instruction algorithm based on LCL filter and a compound current control strategy based on the parallel PI controller and repetitive controller in synchronous rotating dq frame are proposed,which effectively reduces the low-order harmonics of grid current,achieves the positive/negative current tracking without steady-state error and enhances the DC voltage stability.The scheme of active damping by filter capacitor current is applied to suppress the transient resonance of LCL filter.Experiment with a 5 kW prototype verifies the correctness of the proposed control strategy.