A Three-Phase Semi-Single Stage PV Inverter With Voltage Boosting and Leakage Current Minimization

Abstract

This brief presents an integrated three-phase transformerless inverter configuration for PV systems, which is capable of synthesizing a three-level (3L) voltage waveform at its output from a single PV source. Furthermore, high-frequency transitions in the voltage across the parasitic capacitive branch are altogether eliminated for effective suppression of the leakage current, which is of paramount interest in transformerless PV systems. It is shown that the proposed configuration is capable of achieving a voltage boosting factor of two with the aid of an interleaved dual-output buck-boost converter. The efficiency of the proposed power converter is considerably improved, as a significant amount of the PV power is transferred directly to the load. Further, mathematical equations are derived using the theory of switching functions to assess the amount of power that can be transferred directly to the load via inverting stage. Experimental studies validate the operating principle of the proposed power converter configuration in both steady-state and dynamic conditions.