High-speed torque control of brushless permanent magnet motors

A method of converter control that improves the high-speed torque of brushless permanent-magnet (PM) motors is presented. The method consists of modulating the converter conduction intervals and their phase relative to the rotor position in order to deliver current to the stator windings at high speeds where the motor back EMF approaches the convertor rating. A microprocessor-based controller is used in the implementation. With this control, operation of the PM motor drive at its maximum ratings can be extended to higher speeds.<
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