Modeling, analysis, and impedance design of battery energy stored single-phase quasi-Z source photovoltaic inverter system

The battery energy stored quasi-Z-source (BES-qZS) based photovoltaic (PV) power generation system combines advantages of the qZS inverter and the battery energy storage system. However, the second harmonic (2ω) power ripple will degrade the system's performance and affect the system's design. An accurate model to analyze the 2ω ripple is very important. The existing models did not consider the battery, and with the assumption L1=L2 and C1=C2, which causes the non-optimized design for the impedance parameters of qZS network. This paper proposes a comprehensive model for single-phase BES-qZS-PV inverter system, where the battery is considered and without any restriction of L1, L2, C
₁
, and C
₂
. A BES-qZS impedance design method based on the built model is proposed to mitigate the 2ω ripple. Simulation and experimental results verify the proposed 2ω ripple model and design method.