Z源逆变器并网独立双模式控制策略研究

摘要

Considering the low response speed of the constant capacitor voltage control strategy, this paper proposes a double closed-loop control strategy to improve the response speed, which is based on the capacitor voltage outer loop and inductance current inner loop. This paper proposes the Z-source inverter model in grid-connected and stand-alone modes, where the former achieves the interconnection with unit power factor and the latter ensures the stability of the output voltage. To deal with the big electromagnetic inertia of Z-source topology, the model chooses a corrected modulation control in the switching process from grid-connected to stand-alone mode, and uses the Z-source inductance current gradual increase control in the switching process from stand-alone to grid-connected mode, therefore achieves seamless switching between the two modes.%针对Z源逆变器电容电压恒压控制策略响应速度较慢的问题，提出了电容电压外环、电感电流内环双闭环控制策略，提高了系统的快速性。设计了Z源逆变器的并网和独立模型，并网模型实现了单位功率因数并网，独立模型保证了输出电压稳定。切换过程考虑到Z源逆变器电磁惯性大，电容电压、电感电流不能突变的特点，在并网到独立切换过程采用修正调制信号，在独立到并网切换过程采用Z源电感电流渐增控制，实现了双模式的平滑切换。