APPARATUS FOR MONITORING RESIDUAL CURRENT OF TRANSFORMER-LESS PV INVERTER

摘要

A device for monitoring a leakage current of a transformer-less photo voltaic inverter according to the present invention calculates a resistance component of a leakage current in connection with a transformer-less photo voltaic inverter. A peak value and a phase are obtained through a PLL after only an AC component is left by eliminating a DC component of a leakage current sensed by a zero current transformer (ZCT). And, an effective value of the AC component is obtained and a DC value is added to the effective value to calculate the value of a resistance component of the leakage current. System accidents occurring when the inverter operates and injury risks of a user can be reduced by classifying and measuring the resistance component of the leakage current occurring when the transformer-less inverter operates.