Selection of Impedance Network Parameters for Three-Phase Voltage-Fed Quasi-Z-Source Photovoltaic Grid-Connected Inverter with High Boost Capacity

摘要

In order to solve the conventional quasi-Z-source inverter's defects including small boost factor, limited boost capacity and high voltage stress on power transistor at low input voltage, a three-phase voltage-fed quasi-Z-source photovoltaic grid-connected inverter with high boost capacity is presented in this paper. And the influence of system dynamic performance and modulation strategy on impedance network parameter is detailed analyzed. On the one hand, the smaller inductance and larger capacitance of impedance network are better for the dynamic performance through the zero-pole map of capacitor voltage close loop, and that is verified by load changed transient simulation. On the other hand, the values of inductance and capacitance of impedance network are different under different modulation strategies.