Permanent magnet AC motor full speed range operation using hybrid sliding mode observer

This study focuses on the development and application of full speed range operation of permanent magnet (PM) AC motors (including PM synchronous motor (PMSM) and brushless DC (BLDC) motor) using hybrid sliding mode observers. Specifically, investigations are made under full load starting, sensorless technology and flux weakening control.; The first topic of this study is to analyze the PM spindle motor using finite element analysis (FEA). First the generation of the sinusoidal back-EMF in the spindle motor is investigated. For the sinusoidal PM motor, the condition for producing positive torque is studied when the numbers of stator poles and rotor poles are different. Flux-weakening capability is evaluated in order to prevent the demagnetization of the permanent magnet rotor.; The second topic of this study is to develop an adaptive full-speed range control system of the PM spindle motor considering sensorless technology. Full-load starting and over the rated-speed operations are given more consideration. Adaptive rules are applied to ensure motor performance when motor parameters vary over the full speed range. A hybrid sliding mode observer is developed to estimate the rotor position and speed. MATLAB SIMULAINK is used to verify the basic performances of the overall control system.; Third, a novel full-speed range control system for the brushless DC motor is developed. Unlike the conventional six-step current control, which is said to have poor performance during the flux weakening operation, the developed method can achieve the same controllability as in the sinusoidal PM motor over the flux weakening operation. It can also operate with an increasing motor torque. As the PMSM does, a hybrid sliding mode observer is developed to provide the rotor position and speed. Simulations have been done by using MATLAB SIMULAINK to verify the feasibility of the proposed algorithm.; Finally, experiments have been done at the Whirlpool Corporation to verify theoretical analysis of the proposed PM spindle motor drive system. Texas Instruments digital signal processor, TMS320F2407DSP, is used as the controller. Through the embedded measuring coils and coupled dynamometer, the motor performance over full-speed range has been evaluated. Furthermore, the developed algorithm was put into practice and tested in the prototype Direct-Drive washer.