改进的感应电机直接转矩控制系统

Research on Improved Direct Torque Control System of Induction Motor

基于三电平逆变器的感应电机直接转矩控制无速度传感器系统存在着逆变器结构复杂、元器件使用较多、基于转子磁链定向的无速度传感器算法使磁链计算复杂、磁链观测环节不精确等问题。为解决上述问题，对三电平逆变器的拓扑结构进行简化，针对直接转矩控制的特点，采用基于定子磁链的无速度传感器算法，并与改进的磁链观测器相结合，进行速度观测，构建了改进拓扑结构、改进磁链观测算法的感应电机直接转矩控制无速度传感器系统。通过仿真实验验证了上述改进方法在减少开关器件损耗的同时，可提高磁链观测精度，使转速估算更精确。

Direct torque control of induction motor three-level inverter speed sensorless inverter system has complex structure, more components,complex flux algorithm due to speed sensorless algorithm based on rotor flux orientation, and inaccuracy of flux observation. To solve the above problems, the topological structure of the three-level inverter is simplified for direct torque control. The speed sensorless algorithm is adopted based on stator flux, and combined with the improved flux observer to observe speed. A modified topology and improved flux observer algorithm of direct torque control of induction motor speed sensorless system are established. The simulation experiments show that the improved method can reduce the loss of the switch device, and improve the precision of the flux observation. It make the speed estimation more accurate.