Advanced phase-skipping control with improved efficiency of three-phase micro-inverters

In the three-phase micro-inverter developed at the Florida Power Electronic Center (FPEC), maximum efficiency is achieved when it is operating at close to its rated power. At lower power, load independent loss becomes a larger part of the overall loss and negatively impacts efficiency. It is therefore advantageous to operate each phase as close to its rated power as possible. One way to accomplish this is to implement a phase-skipping mode of operation. This paper explores the benefits of advanced phase-skipping control of a three-phase micro-inverter, wherein one or two phases may be disabled depending on the available power in order to maximize the power in the remaining phases. The experimental results on a 400-W three-phase micro-inverter confirm the efficacy of such a control technique which will be shown using experimental results and CEC weighted efficiency calculations compared to normal three-phase operations. An improved inverter efficiency has been achieved using this control method.