Analysis and mitigation of leakage current and dc injection in transformerless pv inverter topologies

Abstract

The solar panel efficiency is still a major hindrance in the popularity of solar PV systems Considering the 10 15 efficiency of commercially available solar panels the reliability and efficiency of the power electronic interface should be ensured Initially residential PV systems used low frequency transformer between the inverter and grid The low frequency transformers are bulky and increased the weight size and cost of the system An alternative was the use of high frequency transformers between DC DC conversion stages but even though the issue of weight size and cost was reduced the overall system complexity increased There was no significant improvement in system efficiency with high frequency transformers From 1995 the use of transformerless inverters was encouraged Countries like Germany changed their regulations to incorporate the use of transformerless inverters Due to the advancements in technology transformerless inverters are gaining a lot of importance in PV market By avoiding the transformer in the output of PV inverter cost can be reduced by 25 and efficiency can be increased by 2 Also the size weight and system complexity can be reduced When there is no transformer connected between the PV inverter output and the grid the problems of leakage current and DC injection creep up newline