一种单相并网逆变器电流相位的补偿方法

摘要

针对单相并网逆变器中,传统电流PI控制算法下的并网电流与电网电压存在相位差,尤其是在电流较小时相位差比较严重,导致逆变器输出功率因数较低的问题,提出了一种减小并网电流与电网电压相位差的控制方法.通过理论分析计算,得到不同的控制参数和电流给定情况下,并网电流与指令电流之间相位差的数学表达式,然后在指令电流中进行相应的相位补偿,从而减小并网电流与电网电压的相位差,提高逆变器的输出功率因数.最后,通过实验与理论计算进行对比,验证了该方法的可行性.%A control strategy is proposed to improve the quality of the grid-connected current for single phase inverter. The grid-connected current usually has a small phase shift with the grid voltage by employing traditional PI control algorithms and the phase shift increases if the output current is lower.This paper analyzes the phase shift and gives an exact mathematical expression of it.Then compensation can be done in the current reference.As a result,the phase shift can be decreased and a high power factor can be achieved.The control strategy is verified by experiment with satisfied results.