Predictive-DPC Based on Duty Cycle Control of PWM Rectifier under Unbalanced Network

Abstract

This work proposes a predictive direct power control (P-DPC) technique of a PWM rectifier, based on a duty cycle control method, using a new definition of the instantaneous reactive power in the predefined cost function, able to operate under balanced and unbalanced grid voltages. In conventional DPC, the use of a single voltage vector during a control period leads to high power ripples and variable switching frequency. To overcome these problems, a duty cycle control is introduced in P-DPC to achieve performance improvement in terms of power ripple reduction, dynamic response and robustness against unbalanced grid voltages. Its main characteristic is the use of several voltage vectors applied during a control period. In effect, the duration of the selected vector is determined by minimizing the active power ripple during a control period. Simulation results are presented to confirm the theoretical study developed.