Research On Efficient V/F Control Method For Permanent Magnet Synchronous Motor

By virtue of excellent performance like high torque inertia ratio, high powerdensity and high efficiency, and characteristics such as simple structure, small size,light weight and reliable operation, permanent magnet synchronous motor (PMSM)has been widely used in industrial and agricultural production, the daily life, theaerospace and defense and other fields.This project aims at building a low-cost, practical permanent magnetsynchronous motor control system experimental platform. In reference to a largenumber of relevant literatures, on the basis of contrast with vector control and V/Fopen-loop control, the research is cut in from the problems appeared in V/F open-loopcontrol system of permanent magnet synchronous motor. Then, theoretical andexperimental studies of efficient V/F control method for permanent magnetsynchronous motor is carried out, which is based on SVPWM tactics.An efficient V/F control method of permanent magnet synchronous motor ispresented in this paper, by detecting current to calculate reactive power, controllingthe proportional gain to attain constant reactive power, thus forming two stableclosed-loops to compensate for the stator voltage and speed. This kind of controlmethod is a simple algorithm, regardless of introducing any speed and positionfeedback signal from the motor side, not only avoid the Park transformation, speedand current loop control and the rotor position angle observer required for vectorcontrol, but also achieve the maximum torque current ratio. In this paper, firstly theadvantages and disadvantages of various control methods for permanent magnetsynchronous motor is discussed, and then the stability analysis of V/F open-loopcontrol system for permanent magnet synchronous motor is executed. In order tosolve the rotor oscillation and reload out-of-step issue of the V/F control, the stablecontrol method is proposed, just increases the speed compensation. Under the premiseof maintaining system stability, for purpose of the largest output torque at the samecurrent magnitude, an improved efficient V/F control method is put forward viacompensating for the speed and stator voltage at the same time.Finally, a permanent magnet synchronous motor V/F control system simulation model is established in the Matlab/Simulink platform, and the model is used toexperiment on no-load starting and load starting simulation. On the basis oftheoretical analysis, by use of TI’s control chip TMS320F2812, an efficient V/Fcontrol system experimental device platform of permanent magnet synchronous motoris build. Followed by is the system debugging and analysis on the proposed efficientV/F control experiment. Experimental results show that efficient V/F control methodcan achieve excellent speed-sensorless control of permanent magnet synchronousmotor, and has good stability.