태양광 발전 시스템의 인버터 단락사고 발생 대응을 위한 레그 절체 방안의 적용 및 검증

Abstract

In this paper, we propose a countermeasure technique by leg transfer switch in case of an inverter short-circuit fault for application to a PV generation system. In general, inverters operating in a 3-leg manner are used to obtain output AC power from input DC voltage. However, if a short-circuit fault occurs in an inverter operating in a 3-leg method, a problem occurs in power supply. As a countermeasure against this, we propose a leg transfer switch method that changes the 3-leg method to a 2-leg method without replacing the power semiconductor. If the leg transfer switch method is used, power can be supplied normally by switching the legs of the inverter. In addition, it was verified through simulation to verify the leg transfer switch method. As a result, when a short-circuit fault occurred in the inverter operating in the 3-leg mode, it was possible to transfer power normally by converting to the 2-leg method using the leg transfer switch method.