降电容电压型准Z源三电平逆变器及其恒功率并网控制

Quasi Z-source Three-level Inverter with Reduced Capacitor Voltage and Its Constant Power Grid-connected Control

针对传统Z源三电平逆变器的Z源网络电容电压应力大、启动时存在冲击电流等问题,提出一种新型的准Z源中点钳位式（NPC）三电平逆变器拓扑结构,并对其并网控制方法进行研究。首先,分析了新型准Z源NPC三电平逆变器的结构和工作原理;然后将恒功率控制策略引入到准Z源NPC三电平逆变器的并网控制中,并结合SVPWM调制策略实现了逆变器并网控制;最后,进行了软件仿真与硬件实验。结果表明：准Z源NPC三电平逆变器能够减小Z源网络电容电压应力,并网控制方法能够实现逆变器输出的有功、无功功率有效跟踪设定值,且并网电流谐波含量较低。

To solve the problems that the voltage stress of traditional Z-source three-level inverter capacitor is high and huge inrush current exists when starting-up,we proposed a new quasi Z-source NPC three-level inverter topology and researched its grid-connected control method.First,we analyzed the structure and working principle of the new quasi Z-source three-level neutral point clamped（NPC） inverter;then,we introduced a constant power control strategy to quasi Z-source three-level NPC inverter grid-connected system.Finally,software simulation and hardware experiment were carried out.Experimental results show that the quasi Z-source three-level NPC inverter can reduce the voltage stress of the Z-source network capacitor,andthe control method can realize the effectively tracking set values of the grid inverter output active and reactive power with low current harmonic content.