| This dissertation develops a new method of sensorless control for brushless d.c. motors. The new sensorless control method utilizes relative rotor position feedback information, which is extracted from the sensed current waveforms.;In this work, the justification of sensorless control, and the requisite conditions of this type of sensorless control implementation are given. An evolutionary technological and business basis for this justification are presented. Brushless d.c. fundamentals were covered to the extent that information pertinent to this work is imparted. Details of the new method of sensorless brushless d.c. control, the Synchronous Misalignment Detection/Correction technique (SMDC), were revealed. A theoretical basis was first developed considering the electrical and magnetic aspects of the control, drive, machine, and load interactions. Existence and uniqueness of the hysteresis waveform feedback information were developed, and a sensitivity analysis performed which unveils the extent of variations of the detected feedback information to changes in machine and drive parameters. A simulation of the two modes of SMDC control were performed, and the results discussed. Experimental validation of the simulations and method was accomplished. Ideas are given for possible extensions and future work. |
