微逆变器过零点电流畸变抑制的混合控制策略

微型光伏并网逆变器输出电流过零点畸变会导致电网注入电流谐波增加,严重时还会干扰电网正常运行。为解决该问题,通过对反激式微逆变器峰值电流控制策略的分析,讨论了功率器件关断延迟时间对系统功率平衡的影响,指出功率器件关断延迟时间是造成过零点畸变的主要原因,据此提出了一种新的混合峰值电流控制策略。详细分析了其工作原理,给出了控制实现方法,并构建了100 W样机进行实验。实验结果表明所提出的混合控制策略能有效抑制输出电流过零点畸变。

Hybrid control strategy for suppressing zero-crossing current distortion of micro-inverter

The zero crossing distortion of micro-inverter output current can increase the THD of grid current, in severe cases it can disturb the normal operation of the grid. To resolve this problem, through the analysis of peak current control strategy of flyback type micro inverter, the effect of switching delay time of power electronic elements on power balance is discussed in detail, that the switching delay time is the main cause of zero crossing distortion is pointed out, thus a new hybrid peak current control strategy is presented. The control theory is analyzed in detail and a controller is designed. A 100 W micro-inverter prototype is built to verify the proposed control method. Experimental results show that the proposed control strategy can suppress the zero crossing distortion effectively.