A control strategy to compensate for current and voltage measurement errors in three-phase PWM rectifiers

Abstract

This study proposes a compensation strategy to deal with both current and voltage measurement errors in the three-phase PWM rectifier system. The DC offset and scaling errors in the voltage and current measurements cause the injection of undesired DC and unbalanced currents into the three-phase input current and subsequently lead to voltage ripple at the DC output voltage. This paper proposes a compensation scheme for current measurement error where the DC offset and scaling errors in the current measurement are estimated from the characteristic of the DC output voltage ripple combining with simple band-pass and low-pass filters. Meanwhile, an advanced current controller designed with a proportional integral plus two resonant controllers tuned at the fundamental grid frequency (ω s ) and 2ω s in the synchronous (d-q) reference frame is suggested to reject the impact of the DC offset and scaling errors in the voltage measurement. The proposed compensation method is developed without the need of extra hardware circuit, sensor, or precise information of system parameters so that it can be considered as more cost effective and robust solution. The effectiveness of the proposed solution is verified by experimental results.