Modelling and controller design of quasi-Z-source inverter with battery-based photovoltaic power system

The quasi-Z-source inverter (qZSI) with battery can balance the stochastic fluctuations of PV power injected to the grid/load, but there is no literature to disclose its modelling and controller design in detail. This study proposed a dynamic small-signal model of qZSI with battery and a control strategy for photovoltaic (PV) power generation system. The built model discloses the dynamic relationship of PV panel voltage, battery current, quasi-Z-source inductor currents and capacitor voltages. The proposed control method achieves the grid-tie operation with unity power factor, PV panel´s maximum power point tracking and battery management. The novel space vector modulation for the qZSI divides the total shoot-through time interval into six equal parts per control cycle to be combined into the six switching moments, and lower inductor current ripple and higher inverter efficiency are performed. The experimental and simulation results verify the theoretical analysis and proposed control methods.