Minimized Quasi-Z source network for single-phase inverter

The single-phase quasi-Z source inverter topology (qZSI) is attracting attentions for the single-phase grid-tie photovoltaic applications. However, due to the inherent second harmonic power flow in a single phase system, a large qZS network is required to reduce the second harmonic components of current and voltage at the dc port. Minimization of this qZS network remains an open research topic. This paper proposes a design method for the single-phase qZSI topology to minimize the qZS capacitance and inductance. A second harmonic power flow model for the single-phase qZSI is derived and ripple power is analyzed for the minimization solution of the qZS network. A current ripple damping control is proposed to ensure suppression of the second harmonic power flow in the inductor. The proposed design and conventional design methods are compared through design examples, simulation comparison, and experimental verification. These results verify the proposed minimization design method.