Research on Control Strategy of Phase Shifted Full Bridge Converter Based on Pulse Load Current Feedforward

In order to solve the problem of slow dynamic response of the system under the condition of pulse load, this paper takes the phase-shifted full-bridge converter as the research object, and proposes a constant voltage control strategy based on load current feedforward. Firstly, the open-loop equivalent impedance and closed-loop equivalent impedance of the system are analyzed through the small-signal model of the phase-shifted full-bridge converter, and the effect of closed-loop equivalent impedance on the constant voltage control is discussed. Then it is pointed out that reducing the closed-loop equivalent impedance of the system can reduce the disturbance of the output voltage caused by sudden load change. A feedforward control strategy of the load current is proposed and the feedforward controller is designed from the Angle of reducing the closed-loop equivalent impedance. Finally, the simulation results show that the dynamic response speed of the system is improved significantly after the load current feedforward control is added, which can effectively suppress the disturbance of constant voltage output when the pulse load changes.