Topology for current-source grid-connected inverter with improved efficiency and pulse width modulation control strategy

Abstract

A novel topology of the current-source grid-connected inverter is proposed based on the immittance converter theory. A control strategy of sine-sine pulse width modulation (PWM) is studied. Compared with the traditional current-source inverter, the power frequency inductors and power frequency transformer are replaced with high frequency inductors and a high frequency transformer. Thus, the proposed inverter has advantages of small volume, low cost, low total harmonic distortion (THD), low power losses, high power factor (PF) and simple control. Furthermore, grid voltage cannot influence output current of the grid-connected inverter and the current-source inverter with a high PF that approaches one has been realized. Finally, validity of the theory analysis and feasibility of the control scheme are shown by simulation and experimental results.