Improved Deadbeat Predictive Direct Power Control for Three-Phase PWM Rectifier With Reduced DC Voltage Fluctuation Based on LADRC

Three-phase voltage source pulsewidth modulation rectifiers with deadbeat predictive direct power control (PDPC) have been extensively studied for their simple concept and satisfactory performance. However, conventional deadbeat PDPC strategies exhibit a slow dynamic response to load disturbances and demonstrate active power errors under steady-state conditions. To enhance the dynamic response, this paper proposes a linear active disturbance rejection control (LADRC) with an adaptive virtual capacitance method in the outer voltage loop. This enhancement provides a virtual active power component, that enables immediate power tracking under load disturbances. Additionally, a feedback correction method is implemented to predict the active power reference accurately and eliminate steady-state active power error. The design of parameters, disturbance rejection capabilities, and stability analysis of the proposed LADRC with adaptive virtual capacitance and feedback correction (LADRC-AVCFD) strategy are presented comprehensively. A 1.5 kW prototype was constructed, and experimental results indicate a complete elimination of steady-state active power errors, a 75% reduction in DC voltage fluctuations, and an 81% decrease in settling time under load disturbances.