Photovoltaic Power injected to the Grid with Quasi Impedence Source Inverter

The Z-source inverter (ZSI) with battery operation can balance the stochastic fluctuations of photovoltaic (PV) power injected to the grid/load, but the existing topology has a power limitation due to the wide range of discontinuous conduction mode during battery discharge. This paper proposes a new topology of the energy stored ZSI to overcome this disadvantage. Two strategies are proposed with the related design principles to control the new energy stored ZSI when applied to the PV power system. They can control the inverter output power track the PV panel maximum power. The voltage boost, inversion, and energy storage are integrated in a single stage inverter. The obtained results verify the theoretical analysis and prove the effectiveness of the proposed control of the inverter’s input and output powers and battery power regardless of the charging or discharging condition.