Control of SiC based front-end rectifier under unbalanced supply voltage

A voltage source converter is used as a front end converter typically. In this paper, a converter which is realized using SiC MOSFET is considered. Due to SiC MOSFET, a switching frequency more than 50 kHz can be achieved. This can help increasing the current control loop bandwidth, which is not possible with the Si based converter switching with 10-20 kHz. Due to increased current controller bandwidth, it is possible to control the negative sequence current without a separate negative sequence current controller. This paper presents a new feedforward controller for the negative-sequence current together with a positive-sequence current controller for the front-end rectifier. A gain in the feedforward term can be changed to control the negative-sequence current. Simulation results are presented to verify the theory.