真空泵用屏蔽电机无传感器残压重投控制策略

Residual voltage restart control strategy with sensorless of canned motor for vacuum dry pump

针对真空干泵机组故障、生产工艺需要等原因影响真空设备产线在线运行时间的问题,研究真空干泵用屏蔽式感应电机带速重投策略,寻求重投的有利时刻以保证带速重投的成功,对电机断电后的转速和定子失电残压特性展开研究。为此,根据屏蔽感应电机空间向量模型,建立基于电压电流混合磁链观测的无速度传感器估算模型、推导电机断电期间的转速估算方法以及定子失电残压解析式。通过重点研究定子残压和虚拟重投电压间幅值特性和相角特性,确定控制系统的首次重投点和其次重投点。以4 kW真空干泵用屏蔽感应电机机组为例,通过模型仿真和失电残压实验验证了该控制方法在泵类工程中有较好的适用性和准确性,重投阶段的转速稳定时间为0.5 s以内,重投阶段的冲击电流平均减小59.18%。

To discuss the problem that the on-line running time of the vacuum equipment production line is affected by the failure of vacuum dry pump unit and the need of production process,it is very significant to study the strategy of restarting at unknown speed of the canned induction motor for vacuum dry pump.In order to find the optimal moment of restarting and ensure the success of restarting at unknown speed,it is necessary to study the speed of motor and the stator residual voltage characteristics after the power off.Therefore,according to the space vector model of canned induction motor,a speed sensorless speed estimation model based on flux observation of voltagecurrent hybrid rotor was established,and the speed estimation method during the power off and the analytical formula of stator residual voltage after power off were deduced.By focusing on the amplitude and phase-angle characteristics between the stator residual voltage and the virtual reinput voltage,the first and the secondary restart points of the control system were determined.Taking the canned induction motor unit for 4 kW vacuum dry pump as an example,through model simulation and power-off residual voltage experiment,the good applicability and accuracy of the control method in pump engineering were verified,the speed stability time is less than 0.5 s,and the impact current decreases by 59.18%on average.