Research on tuning method of PID controller parameter for hybrid magnetic bearing

The PID controller parameters directly affect the dynamic characteristics of the hybrid magnetic bearing (HMB) system. However, currently, control parameter tuning mainly depends on experience and lacks the support of design theory. In this paper, the control parameter tuning method was studied to solve this problem. First, the expressions of equivalent stiffness and equivalent damping of the system were established, and the effects of each control parameter on the support characteristics of the system were analyzed separately. Then, based on the dynamic response results of the system, the tuning principles of control parameters were obtained: the proportional gain and derivative gain value ensure that the system works with “natural stiffness” and “natural damping”. The integral gain and time constant value ensure a positive damping ratio near the nature frequency. Finally, the method of this paper was applied to complete the PID controller design. The simulation and experiment results show that the rotor can maintain stable operation under different frequency excitations. The results are in good agreement with the theoretical analysis results. The conclusion of this paper provides helpful guidance for tuning control parameters and speeding up the development process of magnetic bearing systems.