The Hefei Advanced Light Facility (HALF) is a fourth-generation synchrotron radiation source based on a diffraction-limited storage ring. Its electron beam energy is 2.2 GeV, with an emittance target of less than 100 pm·rad which requires stability within 5×10^-5 for the magnet steady-state power supply and reduces overshoot in step response when changing the current operating point. Due to the need for over a thousand magnet steady-state power supplies at HALF, the empirical tuning method using conventional proportional-integral-derivative (PID) controller parameters requires a significant amount of time.

This study aims to design a PID controller parameter auto-tuning algorithm for the magnet steady-state power supply of HALF, to achieve optimal PI parameters.

Based on polynomial regression and genetic algorithms, an auto-tuning algorithm for PI controller parameters was developed for the magnet steady-state power supply controller. Then, BUCK circuit structure was adopted for the magnetic steady current power supply, and the simulation and physical experiment verification of the prototype of the magnetic steady current power supply were carried out. Finally, this algorithm was integrated with the supervisory computer system to record various data points. Development and testing of this algorithm were conducted on the magnet steady-state power supply to verify the stability of the output current.

The test results of the power supply step response and output current stability show that the step response achieves a smooth transition, and the rising speed is increased several times. The output current stability is within 1×10^-5. The key technical indicators meet the operation requirements and significantly improve the debugging efficiency.

The algorithm proposed in this paper provides an effective method for improving the debugging efficiency of large-scale power supplies in the future.