A leading current compensation control in three phase PWM AC/DC converter

The voltage and current distortion at the AC utility system due to PWM switching is generated according to the existence of source inductance (Lu). This voltage or current distortion generates electromagnetic interference (EMI) problems in nearby equipment. To solve these problems, an AC filter capacitor is needed to absorb the switching voltage and current distortion. However, the use of the AC filter induces the problem of leading current, and the resonance between AC filter capacitor (Cf) and source inductance (Lu) in the utility system. In this paper, a new leading current compensation scheme for three phase PWM AC/DC converter is presented to reduce the leading current and the resonance of Cf and Lu*Lb/(Lu+Lb). An analysis and experiments are performed to verify the proposed current control scheme by implementing a 6 kW (450 VDC, 16 A), 20 kHz IGBT based experimental circuit.