磁通观测改进的无速度传感器DTC系统

针对定子电阻摄动与积分漂移对直接转矩控制(DTC)性能的影响,在分析直接转矩控制特点的基础上,推导了以电机有功功率为基础的定子电阻辨识算法与以反电动势为基础的定子磁链辨识算法,并将坐标系定向于定子电流矢量上推导出转速估计算法.以此建立的直接转矩控制系统,定子电阻辨识算法不依赖电机其他易变参数,转速估计中未使用转子电阻或转子时间常数;通过4kW感应电机无速度传感器DTC系统仿真试验表明,积分漂移得到有效抑制,估计速度与实际速度良好吻合,系统具有较好调速性能.

Study on sensorless DTC based on flux observation improvement

Stator resistance perturbation and integral drift are two key-factors influencing induction motor direct torque control(DTC) performance.According to the characteristic of flux close-loop control in DTC,a stator resistance on-line identification arithmetic is proposed based on the observation of reactive power,and the steady state stator flux is identified by observing the back electromotive force(EMF).Then,fix the frame on the stator current vector and rotate synchronously(SCO).The speed estimation arithmetic is deduced based on the SCO.In this system,stator resistance identification arithmetic does not depend on motor inconstant parameter,and rotor resistance or rotor time constant is not used in speed estimation arithmetic.The experiment results of the sensorless DTC for the 4kW induction motor are given.It shows the integral drift is effectively restrained,the estimation speed inosculates actual speed well and the system has excellent speed-adjustable performance.