Novel Energy Stored Single-Stage Photovoltaic Power System With Constant DC-Link Peak Voltage

The quasi-Z source inverter (qZSI) with battery can balance the stochastic fluctuations of photovoltaic (PV) power injected to the grid/load, but its existing topology has a power limitation due to the wide range of discontinuous conduction mode during battery discharge. For an energy stored qZSI, traditional control methods cannot ensure a constant dc-link peak voltage because of battery´s voltage clamp. This paper proposes a novel energy stored qZSI-based PV power system with constant dc-link peak voltage to overcome the above demerits. The new topology of energy stored qZSI is employed to improve the power compensation ability of existing topology, new constant dc-link peak voltage control and load related maximum power point tracking are proposed, and the whole system is analyzed in detail. Experimental results verify the theoretical analysis and the proposed energy stored qZSI-based PV power system.