Research On PI Parameters Tuning Of Magnetic Bearings Poweramplifier

The power amplifier of Magnetic bearings and electromagnet coil constitutes theexecution unit of magnetic bearing system. The characteristics of the current outputof power amplifier have an important influence on the stability and dynamicperformance of magnetic bearing system. The command signal of the position loopcan be tracked by the PI controller of power amplifier of magnetic bearings. Most ofthe parameters of traditional PI controller are tuned by using manual tuning method.The parameters of power amplifier with analog controller are tuned by replacing theelectrical components of different values on the circuit board. The PI parameters ofthe digital amplifier are regulated by replacing the PI values. The design of the poweramplifier controller parameters cost a lot of time and human resources. Therefore, theresearch on parameters setting method of power amplifier of magnetic bearings is ofimportant significance.The performance requirements and working principle for power amplifier ofmagnetic bearing is presented in this paper. The models of the analog and digitalpower amplifiers are established separately, and the performance indicators of thepower amplifiers are showed. Based on analyzing the characteristics of the poweramplifier of magnetic bearing, the tuning method of parameters of analog and digitalpower amplifier is studied.The level of self-tuning of parameter in the analog power amplifier is limited forthe using of non-intelligent controller. Firstly, the simulation model of the analogpower amplifier is established. The parameters of the PI controller are tuned inMATLAB, and the expected result is obtained. Then the corresponding parametersare applied to the circuit board and the experiments are conducted on different objects.Though comparing and analyzing the simulation and experimental results, it showsthat these parameters tuned in the simulation model make the power amplifier systemhave a good dynamic performance.The intelligent control algorithms of digital power amplifier of magnetic bearingcan be achieved more easily by using DSP and other digital controllers. In this paper,the improved relay feedback method is choose to identify the critical information of power amplifier system, and PI parameter is adjusted by using the classic Shen-Yutuning algorithm. According to the analysis of simulation, the control algorithm hasthe very good step response for different load.