CONTROL OF PERMANENT-MAGNET MOTOR-DRIVES USING A NEW POSITION ESTIMATION TECHNIQUE

Permanent magnet motor drives require absolute position information so that winding currents can be modulated in synchronism with the rotor. In recent years the eradication of such sensors has been the subject of many publications. This paper describes the principles and implemen tation of a new algorithm for combined flux-linkage and position estim ation in permanent magnet motors. The algorithm uses the machine's flu x-linkage versus current versus position characteristic and is thus ab le to take account of machine nonlinearities. The position estimator u tilizes the characteristic in a generalized nonintrusive estimation sc heme, which is effective over the whole range of operating conditions. The paper shows implementation of the estimator as embedded code in a digital signal processor-based drive system. Experimental results dem onstrate the performance of the algorithm under steady-state and trans ient conditions, when the drive is operating closed loop sensorless, i .e., with the rotor position being provided by the position estimator.