Single Phase Photovoltaic Inverter with Grid Synchronization Using Dual Stage DC-DC Boost Converter

Abstract

Now a days, transformer less inverter for grid connected photovoltaic system getting more attractive because of the benefits like lower cost, smaller in size as well as higher efficiency as compared with the transformer based inverter. However, once a transformer is removed, there is no any kind of galvanic isolation between photovoltaic arrays and grid. There is one another technical problem is the leakage current issue which needs to be escaped carefully. A new H6- type transformer less inverter for grid connected photovoltaic system is proposed that can reduce the problem of galvanic isolation by operating H6 inverter in freewheeling mode. It can also remove the leakage current by maintaining the common mode voltage constant at safe level as per the international standard and also operate with high frequency. In this system, a dual stage DC-DC boost converter is used to reduce the number of series connected PV panel and the effect of partial shading. It can also reduce the cost of full system. Sinusoidal pulse width modulation is used as control strategy to get good quality of voltage at the output of H6 inverter.