Medium voltage 6-pulse CSR with a novel shunt active power filter connection

The 6-pulse controlled ac/dc converter produces harmonics. The input current total harmonic distortion and the input power factor which is firing delay angle dependent are major drawbacks and a compensation technique is mandatory. This paper introduces a compensated 6-pulse current source controlled rectifier with a shunt active power filter, APF, and tapped WYE front-end transformer configuration. The shunt APF is controlled using a predictive current control. It is connected to taps on the front end transformer secondary forming a novel star auto-transformer connection where voltage matching is achieved without the need of a high frequency coupling transformer. Simulation results are presented for a medium voltage converter which is scaled to allow low-voltage experimental confirmation.