永磁直驱风力发电并网逆变器电流滞环控制

Current hysteresis control of grid-connected inverter of permanent magnet direct-drive generator for wind-turbine

永磁直驱风力发电系统网侧逆变器采用单电流环控制时,其稳定性不足,输出电流谐波含量大、电能质量下降。文章分析了含有LCL滤波并网逆变器的数学模型,提出了瞬时功率外环、电流滞环内环的控制策略。通过仿真结果表明,在该控制策略下,并网系统输出的电流波形较好,谐波含量低,具有良好的动态跟踪响应特点,并满足了风力发电并网的控制要求。

When permanent magnet direct-drive wind turbine is connected to the grid, the grid-side inverter with single current loop control will have some problems, such as insufficient system stability, a lot of harmonic content in the output current,and poor system output power quality. Based on the analysis of mathematical model of grid-connected inverter with LCL filter,a control strategy with instantaneous power outer loop and current hysteresis inner loop control is put forward. The simulation results with this control strategy show that the output current waveform of grid-connected system is better, the harmonic content is low, and system has good dynamic tracking characteristics, which can meet the control requirement for grid-connected wind power generation. The reliability and correctness of the control method are effectively proved.