Input Voltage Proportional Feedforward Control for Three-Phase Buck Rectifier Under Unbalanced Input Voltages and Wide AC Input Frequency

In aircraft on-board power supply applications, the wide input frequency brings obstacles for three-phase buck rectifier (3ph-BR) when handling unbalanced input voltages, causing the problem of double-frequency pulsation on active power. To address this issue, an input voltage proportional feedforward control with light computation load and short reconstruction time is proposed in this article, in which the input voltages are reconstructed based on the input voltage feedforward coefficients. A simplified digital implementation for feedforward coefficients calculation is presented for wide input frequency, which only needs six multiplication operations for a set of feedforward coefficients. Besides, the reconstruction time is shortened to less than 1/3 input voltage period. Thus, the proposed control could realize faster reconstruction and impose low computational requirements on digital processors. A 1.2 kW experimental prototype is established to verify the theoretical analysis. The results show that the proposed method realizes low total harmonic distortion (THD) input currents and constant active power under unbalanced input voltages and wide ac input frequency.