基于电流滞环控制的Z源三相光伏并网系统

Z-source three-phase grid-connected PV system based on current hysteresis control

提出了一种适用于Z源三相光伏并网系统的定频电流滞环控制策略。运用三相半桥电路实现滞环控制,解决了直通时间的插入问题,易于DSP实现;采用Z源拓扑进行升压,提高了光伏系统的电流输出能力;采用定频电流滞环控制,不仅具有滞环控制下跟踪速度快、稳定性高、保持并网电流与电网电压同相位的优点,而且由于采用定频控制,降低了开关损耗,简化了滤波电路的设计。Matlab仿真和小功率实验验证了所提策略的可行性。

A fixed-frequency current hysteresis control strategy is proposed for Z- source three- phase grid-connected PV system. The three-phase half-bridge circuit is adopted in hysteresis control to ease the insertion of shoot-through time and the implementation by DSP. The Z-source topology is adopted to boost the voltage and enhance the current output capacity. The fixed-frequency current hysteresis control has fast tracking speed and high stability,which maintains the phase of paralleling current the same as that of grid voltage. The application of fixed-frequency control reduces the switching loss and simplifies the filter circuit design.