直接转矩控制系统的稳定性问题和鲁棒控制器设计

Stability problem and robust controller design of direct torque control system

直接转矩控制(DTC)系统的设计不依赖于感应电机的转子参数,但它的低速性能不好.研究发现,即使定子电阻测量得足够准确,根据定子磁链的电压电流模型设计的经典DTC系统的低速性能仍得不到改善.理论分析说明了这些问题存在的必然性,指出了DTC系统在转矩控制和稳定性之间存在的矛盾,给出了一种鲁棒控制器的设计方案.该方案同时使用了定子电阻和定子磁链的电流模型,当定子电阻和磁链模型出现误差时,表现出了好的鲁棒性.实验结果验证了系统的性能.

The design of the direct torque control (DTC) system does not rely on the rotor parameters of induction motor, but its performance of low speed is not good. It has been discovered that even if the measurement value of stator resistance is precise enough, the performance of the classical DTC system designed by using the voltage-current stator flux model still cannot get improved. By theoretical analysis, the inevitability of problems mentioned above was pointed out. The contradiction between the torque controlling performance and the stability of the DTC system was then analyzed. A kind of robust controller designing method was also presented. In this design, the stator resistance and the current model of stator flux were used at the same time. When the stator resistance and the flux model had errors, the system had a good robustness. The performance of this design was finally verified by the test result.