PWM Current-Source Inverter for Interconnection between a Photovoltaic Array andthe Utility Line

摘要

A 3-phase transformerless power electronic conversion system is used as aninterface between a photovoltaic array and the utility line. Because of the absence of a power transformer, and because of a high array voltage, the efficiency is high. An MPPT is used for optimal utilization of the PV array, which results in a high yield of the system. The power electronic converter is based on the topology of a Pulse Width Modulated Current Source Inverter (PWM-CSI). The inverter is operated at a high switching frequency (20 kHz), so that waveforms with a low distortion are generated, while the power factor is near unity. Two modulations are described, both based on sinusoidal modulation. Preliminary test results are shown.