A Control Scheme for Panel Level Maximum Power Extraction of Solar Panel Companion Inverters

摘要

Solar Panel Companion Inverter (SPCI) is a single stage DC-AC power converter, installed behind each solar panel. Each SPCI synthesizes an AC quasi-square wave voltage with variable pulse width. The width of AC output voltage of each SPCI is proportional to available power on the solar panel. When these voltages are aggregated across multiple solar panels connected in a series string, they synthesize an AC waveform that can be interfaced with the power grid. In this paper, the analysis for synthesizing an AC output voltage synthesized across each SPCI is presented. Also, control algorithm for SPCI, which implements maximum power extraction at panel level is presented. A modified sort and stack algorithm is presented and implemented for Sorted Staircase Modulation and Sorted Pulse Width Modulation strategies. The efficacy of control algorithm is verified in simulations using MATLAB Simulink. Experimental waveforms of a laboratory prototype are presented.