基于模型辨识的磁悬浮电机电力失效补偿方法研究

Study on Power Failure Compensation Method of Magnetic Suspended Motor Based on Model Identification

控制对象模型的准确性直接关系到控制系统性能的优劣。针对传统的在磁悬浮电机电力失效补偿模型中,用一个等效电阻简单替代开关电源模块的磁轴承负载所带来的建模误差较大,控制性能较差的问题,本文首先提出了一种基于扫频原理的间接闭环频域辨识方法,提取出开关变换器闭环各频率点的频率特性后,用最小二乘法拟合出开关变换器控制系统的闭环传递函数,推导出高压DC/DC的开环模型,并在辨识模型的基础上,设计了一种基于模型辨识的数字PID高压DC/DC的控制器,解决了磁轴承系统电力失效后的补偿性能较差的问题。最后,仿真和实验验证了该方法的有效性和可行性。

The accuracy of the control object model is directly related to the merits of the control system per- formance. In order to solve the problem of deviation in switching power supply model and poor control per- formance occurred in traditional compensation method, in which magnetic bearing is replaced by a simple e- quivalent resistance, some research were conducted in this paper. Firstly, based on the principle of frequen- cy sweep, an indirectly closed-loop frequency domain identification method was adopted. The frequency characteristic of switch converter in all frequency points of the closed-loop was extracted. Meanwhile, the least squares method was used to fit out closed-loop transfer function of the control system of switch convert- er. Therefore, the high voltage DC/DC of open-loop can be calculated. Secondly, on the basis of identifica- tion model, a digital PID control of switch power supply according to model identification method was made, which solved the poor compensation performance after a power failure. Finally, the simulation and experi- ment verified the validity and feasibility of the method.