A Novel Real-time Positive and Negative Sequence Components Detecting Algorithm for PWM Rectifier under Unbalanced Operating Conditions

Voltage unbalance in a three-phase system causes performance deterioration of PWM rectifier. Recently, much attention has been paid to the control strategies under such unbalanced operating conditions. However, the detecting of the fundamental positive and negative sequence components with high precision and fast dynamic response is the precondition to guarantee the control effectiveness. In this paper, a novel algorithm for real-time detecting the fundamental positive and negative sequence components has been proposed. Both magnitude and phase angle can be derived by taking advantage of the mathematical relationships among adjacent data in synchronous rotating reference frame. Fast response and high precision enable the proposed method to completely meet the requirements of the unbalance control of PWM rectifier. Simulation results demonstrate the goodness of this algorithm.