改进SMO与I-f启动相结合的PMSM无传感器控制

摘要

为了提高永磁同步电机的无传感器矢量控制性能,在中高速段对传统的滑膜观测器进行了改进,使用sigmoid函数代替sign函数,削弱了抖振.针对传统启动方式抗负载扰动能力差的问题,深入研究了电流闭环的I-f启动策略,预定位后,在电机绕组中输入幅值恒定、频率逐渐增大的旋转电流矢量,实现电机的电流闭环启动.为了设置合适的指令角加速度,引入平均转矩的概念,得到其取值的约束范围.仿真结果表明,I-f启动和基于改进后的滑膜观测器无传感器控制方法能够可靠运行,具有良好的动态性能和抗负载扰动能力.%In order to improve the performance of sensorless vector control of permanent magnet synchronous motor,position estimation based on the sliding-mode observer in the medium-to high-speed range has been improved.Using sigmoid function instead of sign function to restrain the chattering phenomenon.The Sigmoid function is applied to restrain chattering phenomenon.To avoid the problem existing in V-f startup strategy,a so-called I-f starting method is proposed.After pre-targeting,the current in the I-f control is specified and maintained constant in a synchronous rotating reference frame,the motor will be accelerated by following a ramping up frequency command.In order to find a proper value for ramp ratio,the concept of average torque is introduced.The simulation results show that integrate I-f with SMO based control appears to be a better solution to make the whole process smooth and robust.