真空干泵用屏蔽电机无速度传感器带速重投控制系统

Restarting at Unknown Speed with Speed-Sensorless Control System of Canned Motor for Vacuum Dry Pump

针对真空干泵用屏蔽电机带速重投的工程问题,设计基于正弦脉宽调制(SPWM)的调制波模拟器和无速度传感器带速重投系统。该系统将定子绕组空间划分为6p(p为极对数)个扇区,提出利用标准化后的三相定子残压计算扇区内平均转速的方法,同时对电机定子坐标系进行修正,使定子电流空间矢量轨迹接近于理想圆形,抑制重投时电流冲击、转矩脉动和转速波动。设计调制波模拟器,与变频器内部的调制波模块协同完成电机预重投及重投过程。通过模型仿真和22k W罗茨真空干泵机组实验,验证了该定子坐标系修正法及扇区内转速估算法在泵类工程中具有较好的适用性,预重投阶段的转速稳定时间控制在0.6s以内,重投阶段的冲击电流平均减小51.27%。

Aiming at the engineering problem of restarting at unknown speed with speedsensorless of canned motor for vacuum dry pump, a modulation-wave simulator based on the SPWM and a speed sensorless restarting system were designed. The stator winding space was divided into 6 multiplied p sectors in the system, a method for calculating the average speed in sector using standardized three-phase stator residual voltage was proposed. At the same time, the motor stator coordinate system was corrected so that the space vector trajectory of stator current is close to the ideal circle, which could restrain the inrush current, torque ripple and speed ripple of restarting. The modulation-wave simulator was designed to cooperate with the modulation-wave module of the inverter to complete the pre-restarting and restarting process of the canned motor. Simulation and experiment of 22 k W roots vacuum dry pump unit show that this correction method and speed estimation method have good applicability in the pump engineering. The stability time of speed in the pre-restarting stage is within 0.6 seconds, and the impact current during the restarting stage is reduced by 51.27%.