基于新型转子磁链观测器的异步电机转矩闭环矢量控制

A Novel Rotor-flux Observer Based Closed-loop Control on Induction Motor Torque With Vector Orientation

在电动汽车等特殊应用领域,异步电机通常需要直接跟踪主控系统下发的转矩指令。扭矩传感器的安装不仅会增加成本,而且降低系统的可靠性。因此,对电磁转矩的准确观测至关重要。在设计滑模观测器实现异步电机反电动势准确观测的基础上,通过构造反电动势和转子磁链的状态方程,提出一种新型转子磁链滑模观测器。该观测器实现了对转子磁链的准确观测,继而实现了电磁转矩观测及转矩闭环控制。该方案的突出优势在于,转子磁链的观测对转子电阻、励磁电感等电机参数有着较强的鲁棒性。同时,基于此设计的转矩闭环控制系统具有较好的转矩跟踪控制能力。仿真及实验验证了该方案的可行性和有效性。

In electric vehicles or other specific applications, it is usually required for induction motors to track the torque commands issued by the main control system. Installation of torque sensor not only increases the cost of hardware, but also results in the reduction of the system reliability. Therefore, accurate observation of the electromagnetic torque is crucial for motor drive. Based on the accurate observation of the back EMF by designing a sliding mode observer, a novel rotor flux observer was further proposed in this paper by constructing the state equations with the back EMF and rotor flux as variables. Through the proposed observer, the rotor flux was observed accurately, therefore the electromagnetic torque was calculated and the closed-loop control on the torque was realized further. The outstanding advantage of this scheme is that the observed rotor flux is robust to the variations in motor parameters of the rotor resistance, magnetizing inductance, etc. At the same time, the torque control system allows the motor to track the torque commands with high performance. Simulation and experimental results validate the feasibility and effectiveness of the design.