The PREF device is a 10-60 MeV proton synchrotron jointly designed and built by Xinjiang Institute of Physics and Chemistry, Chinese Academy of Sciences and Institute of Modern Physics, Chinese Academy of Sciences, which is the only dedicated device for displacement damage effect simulation test in China. For the technical requirements—the output current frequency of the scanning magnet power supply is 200 Hz, and the tracking error is less than ≤±5×10^-3—of the device, three stage H-bridge series topology schemes are adopted, and the technical requirements are realized based on pulse width modulation through phase shift control. Simulation and test results show that the power supply can output high precision triangular wave current with peak-to-peak value of ±420 A, continuously adjustable amplitude and frequency to meet the requirements of engineering applications.