不对称电网下直驱永磁风力发电机的电流控制

Current Control for the Grid-connected Inverter of Directly-driven Wind Turbine with PMSG During the Asymmetrical Faults

为抑制不对称电网故障下直驱永磁风力发电机并网逆变器直流侧母线电压振荡,在分析直流母线电压波动机理和直驱永磁风力发电机组并网逆变器数学模型的基础上,将陷波器应用在传统锁相环控制算法中,提出了正、负序双电流闭环控制策略,保证系统运行的稳定性。实验结果表明,该策略能有效抑制直流母线电压升高,完成风电机组不脱网运行。

According to the analysis of the fluctuation mechanism on DC voltage and the mathematical model of the three-phase grid-connected inverter of directly-driven wind turbine with permanent magnet synchronous generator during the asymmetrical faults,the notch filter is introduced to conventional control strategy of phase-locked loop and a dual current-loop control strategy which oriented on positive and negative voltage and current respectively is proposed to inhibit the DC voltage fluctuation.Experimental results show that the proposed DCC strategy can prohibit the rise of DC voltage and complete the wind generator un-off-line operation under unbalanced network voltage conditions.