A novel active current injection circuit for adjustable speed drives

Abstract

This paper introduces a novel active current injection circuit to mitigate harmonics and to amend the power factor of a three phase front-end uncontrolled rectifier. The high PF is achieved by injecting HF current, from the HF inverter, at the input of the front-end three-phase rectifier the inverter switches are in zero voltage switching. The front-end rectifier diodes are working in zero current transition. It results a current waveform is continuous and sinusoidal in shape and current harmonics reduced significantly. The fixed duty ratio with varying switching frequency, regulates the output voltage. The input current THD and power factor are 5.76 % and 0.99 respectively. The results are verified through PSIM simulation and compared with an experimental prototype of 2.5Kw.