A PWM Current Source Rectifier with Leading Power Factor

An unidirectional three-phase AC/DC converter is proposed to obtain leading power factor, sinusoidal line current and to keep DC-bus voltage constant without DC link capacitor. Two active switches and two power diodes are used in each converter leg which is different from conventional AC/DC and three level converters. The scheme is adopted with simple commutation procedure to reduce the complexity of control to ensure effective power transformation. Conventional AC/DC converter and three level converters usually have large value of capacitor at the DC side with neutral balancing which will increase the structural complexity. This paper encloses a converter topology with simple commutation procedure to have good voltage transfer ratio capacity, leading power factor and pure sine wave with only higher order harmonics in the line side. By providing small LC filter on the line side even this harmonics can be eliminated. Switches in each leg of same phase will turn on and turn off at zero current. Theoretical analyses and simulation results are provided to verify its performance.