Improved Transformerless Inverter for PV Grid Connected Power System by using ISPWM Technique

摘要

This paper presents an improved transformerlessinverter with common mode leakage current elimination for aphotovoltaic grid connected power system by using inverse sinecarrier pulse width modulation (ISPWM). To eliminate thecommon-mode leakage current in the transformerlessphotovoltaic grid-connected system, an improved single-phaseinverter topology is presented. The improved transformerlessinverter can sustain the same low input voltage as the full-bridgeinverter and guarantee to eliminating common-mode leakagecurrent. The inverse sine carrier pulse width modulation(ISPWM) control strategy can be applied to implement thepresented inverter. The lower total harmonic distorsion andhigher fundamental output voltage are obtained by using theinverse sine carrier pulse width modulation (ISPWM). Themaximum power point tracking (MPPT) is used to extract themaximum power form PV panel. The high efficiency andconvenient thermal design are achieved thanks to the decouplingof two additional switches connected to the dc side of theinverter.