Abstract : This paper introduces the mathematical model of a permanent magnet synchronous motor (PMSM) in a synchronous rotating coordinate system and proposes a parameter identification method for PMSMs with strong engineering application value. The method employs a direct-axis current step response experiment to simultaneously identify the stator resistance and direct-axis inductance, a pulse voltage experiment to detect the quadrature-axis inductance, and a speed drive experiment to detect the rotor flux. Based on the parameter identification results, the design of the current loop and speed loop of the speed control system for the PMSM based on vector control is discussed. Experiments were conducted on an adhesion control experimental platform based on a TMS320F2812DSP. Experimental results show that the parameter identification method is correct and the speed control system has good dynamic and steady-state performance.
Keywords : Permanent magnet synchronous motor; Parameter identification; AC speed control system
1. Introduction
AC permanent magnet synchronous motors (PMSMs) possess advantages such as small size, high efficiency, high torque-to-current ratio, and low moment of inertia. When used as traction motors in locomotive power bogies, they enable gearless single-shaft direct drive, improving the mechanical and electrical efficiency of the traction system. Furthermore, the excitation magnetic field of a permanent magnet motor has a fixed phase relationship with the armature current, simplifying control. These advantages make permanent magnet synchronous motors a new development direction for traction motors. In rail transportation, the adhesion between the locomotive's driving wheels and the rails is the ultimate driving force for locomotive operation. Good adhesion utilization can effectively improve the locomotive's acceleration performance, shorten braking distance, reduce locomotive slippage and coasting, and prevent severe wheel-rail abrasion.
Achieving optimal adhesion control has become a current research hotspot. Against this backdrop, this paper designs an experimental platform for locomotive adhesion control to achieve optimal adhesion control. The main current work focuses on implementing speed control of an AC permanent magnet synchronous motor. The design of the speed control system depends on the motor's electrical and mechanical parameters; therefore, it is necessary to identify these parameters.
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