Supply-side Current Harmonics Control of Three Phase PWM Boost Rectifiers Under Distorted and Unbalanced Supply Voltage Conditions

This paper presents a hybrid current control scheme to minimize the even order harmonics at the dc link voltage and odd order harmonics in the line currents under the distorted and unbalanced supply voltage conditions. The hybrid current control scheme consists of a conventional PI and a repetitive controller (RC). Based on the mathematical model of the three-phase PWM boost rectifier in the positive and negative synchronous rotating frames, the influence of the distorted supply voltages on the line side currents has been investigated from the analytical point of view. The control task is divided into: (a) dc-link voltage harmonics control and (b) line side current harmonics control. In voltage harmonics control, a reference current calculation algorithm has been derived accordingly to ensure that the dc link voltage is maintained constant and the supply side power factor is kept close to unity. In current harmonics control, a plug-in repetitive controller is designed to achieve low THD line currents of the three phase PWM boost rectifier. The proposed analysis and hybrid current control scheme have been validated by experimental test results on a 1.6 kVA laboratory based PWM rectifier. Test results obtained confirm that the proposed control scheme enhances the performance of the PWM rectifier over the conventional one.