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Switch mode sine wave driver for polyphase brushless permanent magnet motor

  • US 5,798,623 A
  • Filed: 02/12/1996
  • Issued: 08/25/1998
  • Est. Priority Date: 02/12/1996
  • Status: Expired due to Term
First Claim
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1. A switch mode sine wave driver circuit for a multiple phase brushless permanent magnet motor comprises;

  • a signal waveform monitoring circuit for monitoring electrical signals appearing at plural motor phase windings of the motor for putting out phase reference signals;

    phase clock generators responsive to the phase reference signals for providing plural phase motor-synchronized clock signals;

    plural phase counters each being clocked by a respective one of the plural phase motor-synchronized clock signals and reset by the phase reference signals for counting motor phase counts of one of plural motor phases within motor phase intervals,a single quadrant sine wave lookup logic circuit separately addressed by the motor phase counts for sequentially putting out digital polyphase raw sine values,phase adjustment logic for adjusting the digital polyphase raw sine values in accordance with rotational position of the motor to provide digital polyphase adjusted sine values,polyphase pulse width modulators responsive to the digital polyphase adjusted sine values for recurrently generating fixed amplitude signed phase pulses having duty cycle duration controlled by the digital polyphase adjusted sine values wherein the sum of durations of signed phase pulses equals zero;

    and,polyphase motor driver bridge circuitry for selectively sourcing and sinking driving currents to and from the plural motor windings in accordance with the fixed amplitude signed phase pulses in order to energize and rotate the motor with switched sine wave drive.

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