Abstract：With unique impedance network and shoot-through, Z-source inverter (ZSI)/ quasi-Z-source inverter (qZSI) can realize buck/boost and DC-AC conversion in a single stage system. It is suitable for grid-connected photovoltaic (PV) power generation systems, where the input voltage varies in a wide range. By taking voltage-source qZSI with continuous input current as an example, this paper provides voltage boost theory and circuit operation principle of the ZSI/qZSI. Based on the demanded mutual limitation of the shoot-through duty ratio and modulation index for ZSI/qZSI, the capacitor voltage range of ZSI/qZSI is investigated and a constant capacitor voltage control strategy is presented for ZSI/qZSI based grid-connected PV systems. The proposed control strategy decouples maximum power point tracking (MPPT) (for power flow control) and grid current control (for power quality); simplifies the controller design; realizes closed-loop control for the ZSI/qZSI grid-connected PV system as well as MPPT. Moreover, the proposed control strategy ensures minimum voltage stress on switching devices when with the same input and output voltage level.
李媛, 彭方正. Z源/准Z源逆变器在光伏并网系统中的电容电压恒压控制策略[J]. 电工技术学报, 2011, 26(5): 62-69.
Li Yuan, Peng Fangzheng. Constant Capacitor Voltage Control Strategy for Z-Source/ Quasi-Z-Source Inverter in Grid-Connected Photovoltaic Systems. Transactions of China Electrotechnical Society, 2011, 26(5): 62-69.
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2011, Vol. 26 
