An Interleaved Switched Capacitor Single-Phase Inverter with a Modified Control Strategy for a Standalone PV System with Battery Storage

In this paper, an interleaved switched capacitor single-phase inverter for a Standalone PV System with Battery Storage is presented. A control strategy based on the combination of P&O MPPT, interleaved battery charging, and an interleaved inverter is developed for effectively control the PV array, battery, and load voltage in a standalone energy management system for a residential property. The advantage of the proposed system is a smaller number of switching devices compared to conventional inverter systems. The inverter used in this study is controlled by phase shifted unipolar sinusoidal PWM with an RMS feedback loop to modulate the reference signal. A review of published literature was conducted to gather data on the performance of current existing topologies such as SPUC, Switched Capacitor and various multi-level inverters. The proposed modified interleaved inverter in this configuration shows improved harmonic performance compared with other existing methods, the simulation of the proposed inverter system recorded a THD of 1.81% for the in-phase output current and voltage. This can be attributed to the interleaving of the switched capacitors that reduces the output ripple of the circuit. A MATLAB/Simulink based simulation circuit was developed and used to validate the proposed modified interleaved inverter. The simulation results show the proposed method is effective for standalone battery-based PV systems.