Research on Double-Frequency Ripple Suppression in the Buck Stage of a Hydrogen Production Power Supply under Three-Phase Grid Unbalance

Aiming at the problem that the output ripple of two-stage hydrogen generation power supply increases under the condition of three-phase power grid imbalance, a three-phase interleaved buck ripple compensation method based on PR/QPR controller is proposed. Firstly, the formation mechanism of the double power frequency component in the instantaneous power of the AC side of the PWM rectifier when the three-phase power grid is unbalanced is analyzed. It is shown that this component will cause the double power frequency ripple in the DC bus, which is transmitted to the output as the input disturbance of the subsequent three-phase interleaved buck. Then, the ripple compensation branch is added on the basis of the original power outer loop, the DC bus ripple component is extracted through the high pass filter, and the PR controller and QPR controller are respectively used to generate the duty cycle compensation to reduce the impact of bus ripple on the output voltage. The proposed method is verified based on MATLAB/Simulink. The results show that both PR and QPR controllers can reduce the output double frequency ripple, but their suppression effects are different under different ripple frequencies. Among them, PR controller has better fixed frequency compensation ability when the ripple frequency is accurate to 100Hz, and QPR controller has better adaptability when the ripple frequency is offset. The proposed method can provide reference for the output ripple suppression control of hydrogen production power supply.