| 摘要 |
An encoder circuit particularly suited for a switched reluctance (SR) electric motor includes a single switch and a plurality of encoder windings. Each one of the plurality of encoder windings is connected to the switch. When closed, the switch initiates current flow through the windings. A plurality of comparators are connected to the encoder windings. Each comparator has an output having a first state and second state. The output changes state when the encoder winding current exceeds a reference current level. A counter connected to the comparator outputs measures the time that each winding current is below the reference current level (i.e., before changing state). The switch simultaneously disconnects the encoder windings from a power supply after each one of the plurality of encoder windings reaches the reference current (i.e, after each of the comparators changes state). A microprocessor connected to the counter outputs determines an angular rotor position using the time that each winding current is below the reference current.
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