改进型Z源逆变器

Improved Z-source Inverter

Z源逆变器能实现升降压变换的功能,同时桥臂不需要死区时间,变换器可靠性高。但传统Z源逆变器中Z源电容电压高于输入电压,同时启动时存在严重的启动冲击,导致变换器体积及重量大、可靠性低。该文提出一种改进的Z源逆变器拓扑。与现有的Z源逆变器拓扑相比,新型拓扑可大大减小Z网络电容电压应力,具有内在的抑制启动冲击电流的能力,从而可使用低压电容以减小系统的体积和成本、增加可靠性。为避免变换器的启动冲击,提出该变换器软启动策略。在理论研究的基础上,基于简单升压控制下的仿真和实验结果验证新型拓扑的优点。

Z-source inverter has the ability like buck-boost conversion and no dead time is needed in phase legs, so high reliability can be achieved. In traditional Z-source inverter, the Z-source capacitor voltage is higher than input voltage, in addition, huge inrush surge exists when start-up, which may cause increase of the equipment volume and weight and decrease of the reliability. A novel Z-source inverter topology was proposed. Compared to previous Z-source inverter topology, it can reduce the Z-source capacitor voltage stress greatly and has inherent limitation property for inrush current, thus low voltage capacitors can be utilized to reduce the system cost and volume. Soft-start strategy was also proposed to suppress the inrush surge. Theoretical analysis, simulation and experimental results under simple boost control were presented to demonstrate the new features of improved topology.