Predictive Direct Power Control for Three-Phase PWM Rectifiers Under Grid Voltage Sags

In three-phase pulse width modulation (PWM) rectifiers, conventional predictive direct power control (PDPC) strategies lead to severe distortion of the input current during grid voltage sags. To address this issue, the compensation power required for the reference power is derived through the power compensation calculation in direct power control. Based on this, a new reference power is formulated, and the switching states are determined via PDPC combined with space vector pulse width modulation (SVPWM). Finally, the simulation results demonstrate that the proposed approach effectively suppresses input current distortion and instantaneous active power fluctuations, enabling normal operation under both balanced and sag grid conditions. A comparison of the simulation results under these two scenarios verifies the effectiveness of the proposed method.