Development of 125kW grid-tied PV inverter and research on efficiency vs. transformer turn ratio

This paper reviewed the development of a 3-phase 125kW grid connected PV inverter and changes in the conversion performance of the inverter based on the gain of the low frequency isolation transformer for isolation between solar and the grid. The 125kW PV inverter consists of a transformer with the grid frequency for isolation between input and output (galvanic isolation) and it has the output power of 60Hz, 3P 3W 380Vac. P&O technique was used for MPPT (Maximum Power Point Tracking) and Active Phase Shift technique was used through changes in reactive power to prevent a islanding operation. Inverter control was achieved based on 16-bit DSP. This paper discussed about the conversion performance of the 125kW inverter in relation to the system and the result of development of THD, MPPT etc and mentioned about the result of comparison of the conversion performance of the inverter based on the efficiency of the low frequency transformer.