Z源光伏逆变器中感性负载的改进控制方法

摘要

简单z源逆变器的控制方法通过在普通SPWM零状态中插入固定直通占空比来获得.该方法虽然实现简单,但是在感性负载情况下,由于换向过程中无法提供续流通道,给输出电压和电流造成严重的崎变.基于产生崎变的机理,提出了一种改进的SPWM控制方法.该方法在换向时提供续流通道,不仅消除由于感性负载引起的输出交流波形的崎变,而且减少了周期内开关管动作个数和次数,有效降低了输出交流的THD和能量的损耗,提高了逆变的效率和质量.通过Matlab/Simulink对改进控制方法进行了仿真,仿真结果证明该方法理论分析的正确性与可行性.%Z-source inverter is normally controlled by simply inserting the fixed shoot-through state into the zero state of SPWM. Because there is no any free-wheel path,serious distortion of output voltage and current may be induced by inductive load. An improved SPWM control is proposed to support the free-wheel path,which not only eliminates the output voltage and current distortion of Z-source inverter with inductive load,but also lowers the switching frequency and decreases the operating switches in one cycle. Simulation with Matlab/Simulink verifies its effectiveness and feasibility.