基于变步长误差补偿的线路阻抗识别方法研究

Research on Line Impedance Identification Method Based on Variable Step Error Compensation

由于可再生能源的发电地域限制,通常情况下可再生能源发电系统需要较长的线路进行并网,因而线路阻抗不可忽略。线路阻抗的存在会加大并网逆变器的控制难度,因此电网阻抗的在线识别有利于提高并网系统的控制精度。提出一种变步长的误差补偿策略,通过采样并网耦合点的电压以及电流,并网耦合点电压经过带通滤波器得到理想电网电压。通过这些信息,结合变步长的误差补偿策略,能够较为精准地识别出电网阻抗。仿真和实验证明了所提出策略的有效性。

Due to the regional limitation of renewable energy power generation, generally, the renewable energy power generation system needs a long line for grid connection, so the line impedance cannot be ignored. The existence of line impedance will increase the control difficulty of grid connected inverter, so the on-line identification of grid impedance is conducive to improve the control accuracy of grid connected system. A variable step size error compensation strategy is proposed. The ideal grid voltage is obtained by sampling the voltage and current of the grid connection coupling point, and then the voltage of the grid connection coupling point passing through the band-pass filter. Through this information, combined with the variable step error compensation strategy, the grid impedance can be identified more accurately. Simulation and experiments show the effectiveness of the proposed strategy.