基于电流误差限定的无轴承异步电机模型预测电流控制

Model Predictive Current Control for a Bearingless Induction Motor Based on Limitation of Current Error

针对无轴承异步电机传统矢量控制中存在电流畸变的问题,提出一种基于电流误差限定的模型预测电流控制(model predictive current control,MPCC)策略。在建立无轴承异步电机离散数学模型的基础上,根据定子电流和定子磁链观测值,预测下一时刻的定子磁链和定子电流。运用电流误差限定策略对每个电压矢量下的电流进行筛选,选取最优电压矢量对应的开关状态作为逆变器的输出状态,从而有效降低开关频率。同时,引入全阶观测器,提高参数观测值的精确度,加快电机的收敛速度。由于系统存在滞后性,对系统进行延时补偿,进一步提高了电机的控制性能。仿真和实验结果均表明,采用所提MPCC策略的无轴承异步电机控制系统,电流畸变有效改善,能实现稳定悬浮,具有良好的静态特性和动态响应特性。

This paper proposed a model predictive current control (MPCC)strategy based on limitation of current error to handle the problem of current distortion in traditional vector control of a bearingless induction motor (BIM).The stator flux and current at the next moment were predicted by using their observations and the discrete mathematical model of the BIM. Then,based on the limitation of current error,all currents under each voltage vector were screened to select switch state corresponding to the optimal voltage vector as the output state of the inverter,which reduces the switching frequency effectively.Meanwhile,the full order observer was introduced to improve the accuracy of parameter observation and accelerate the convergence speed of the BIM.At last,due to the lag of the system,delay compensation for the system was required to improve the control performance of the BIM.The simulation and experimental results show that the proposed MPCC strategy of the BIM can not only effectively improve current distortion,but also implement the stable suspension of the rotor.In addition,it has good static and dynamic response characteristics.