Controller Design and Implementation of Solar Panel Companion Inverters

A solar panel companion inverter (SPCI) is a single-stage dc-ac power converter, installed with each solar panel. Each SPCI synthesizes an ac quasi-square wave voltage with variable pulsewidth. The width of ac output voltage of each SPCI is proportional to available power on the solar panel. Output voltages of SPCIs are aggregated across multiple solar panels connected in series, and a sinusoidal ac voltage is synthesized. In this article, dynamic analysis and closed-loop current controller design of SPCI is presented. Simulation results demonstrating the dynamic response of the closed-loop SPCI are included. The closed-loop current control scheme is implemented on a hardware prototype to demonstrate the grid-tied operation of SPCI, and experimental results are presented. A maximum power point tracking (MPPT) algorithm is implemented for sorted stair-case modulation (SSCM) in MATLAB Simulink. Experimental results demonstrating MPPT operation are presented.