Development of Single Stage Thyristor Based Grid Connected Single Phase Inverter for Renewable Energy Systems

Abstract: Due to increase in the level of pollution and depletion of ozone layer, set-up of new fossil fuel based power generation plants are losing trend day by day and the new trend is moving towards the set-up of renewable resources based power plants. A large number of renewable energy sources based inverters have already been developed to integrate the resources into power system at distribution level. For this purpose, both single-stage and multi-stage converters are being used. Recently, thyristorbaseddc-to-ac converters are also used as low-power, grid connected inverters for solar photovoltaic (PV) applications. This paper proposes a single phase grid-tied inverter which gives lower harmonics in input line current as compared to conventional line commutated grid connected inverters. The proposed converter is analysed in continuous, just continuous and discontinuous modes. The optimum switching condition at which harmonics in the line current isminimum is obtained. The performances of conventional and proposed topology are compared through MATLAB/Simulink based models.

Keywords: Harmonic current, dc-to-ac converters, renewable energy, Total Harmonic Distortion (THD), Magnetic field intensity (H), Flux density (B).