Model Predictive-Based Direct Battery Control in PV Fed Quasi Z-Source Inverters

Abstract

A model predictive-based control strategy for the quasi-Z-source inverter (qZSI) with battery for photovoltaic (PV) power conversion system is proposed in this paper. Usually, in the control of the battery-assisted qZSI, only the injected power to the grid and the maximum power point tracking of the PV are controlled. The battery charges, discharges, or floats depending on the available PV power and demanded power. Thus, a low-frequency current ripple is generated on top of the ripple caused by the shoot through state in the second inductor L2 and the battery. In the proposed approach, the battery current is directly controlled. The power injection is fulfilled with the maximum power capture from PV panels, along with a decoupled active and reactive power control. The validity of the proposed method is proved by using a detailed simulation model, showing a no low-frequency current ripple in both the inductor L2 and battery.