Optimal Input Current Control of Single-phase PET Based on Specific Order Harmonic Compensation

The input and output power difference of single-phase rectifier will generate the low-frequency voltage ripple on the dc-link capacitor. Since the front-end output of single-phase power electronic transformer (PET) is not connected to the load, the hardware low-pass filter can be cancelled or the dc-link capacitance can be reduced. After releasing the constraints of dc-link voltage fluctuation, the low-frequency voltage ripple will increase the input current total harmonic distortion (THD) and reduce the input power factor (PF). A specific order harmonic compensation strategy is proposed in this paper to reduce the harmonic and reactive current in the grid. Simulation and experimental results show that the proposed control strategy can significantly reduce THD and increase PF when the dc-link capacitance is reduced.