| 摘要 |
An electronic system utilizing dynamic inductance changes in the windings of an electric motor to measure and monitor mechanical position. The method employs the AC component of the Pulse-Width Modulation (PWM) which is commonly used to drive motor windings without the need for injected AC signals or external position sensors. When a winding of the motor is driven with such an AC signal, the winding inductances form a voltage divider across the center node of a Y-connected motor. Inductance changes in the windings occur as the poles of the rotor pass by the poles of the stator. Considering the PWM drive as an AC stimulus, the voltage response at the center node varies with these inductance changes in the legs on either side; this amplitude variation corresponds to a measurement of rotational position. These measurements provide position/velocity feedback to a servo controller as long as current runs through a motor winding. This position sensing also applies to sensorless control of commutation in brushless DC and switched-reluctance motors.
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