Analysis and Control of Quasi Z-source Inverter with Digital Current Control for Energy Storage

The impedance source-based inverter has several advantages in the field of Photovoltaic (PV) systems. It overcomes several drawbacks of conventional PV systems because of its capability to invert and boost the available input voltage through a single power conversion stage. The paper focuses on a quasi-impedance source topology which has several advantages over traditional PV inverter and other traditional impedance source inverters. Application of energy storage to such a topology makes it more suitable for both standalone and grid applications. Thus the paper includes energy storage single-phase impedance source inverter for a standalone PV application with the key elements such as feed-forward MPPT control, output voltage control and a new implementation of digital current control for the bi-directional converter which operates on the available intermittent nature of the PV power. Thus this paper includes a detail numerical and operational analysis of the topology and the control mentioned above, followed by simulation and hardware verification of the above configuration.