Allen-bradley Company, LLC

David J Morris

Ernst H Dummermuth

Michael F Korba

A resolver driver circuit uses sine and cosine values stored in a read only memory to generate sine and cosine waveforms by sequentially reading the stored values and passing them through a clocked data latch to a digital-to-analog converter. The output of the digital-to-analog converter is filtered to remove quantization error. Phase error produced by the filtering and other sources is detected by timing the zero crossings of the sine and cosine waveforms and comparing them to a master synchronization signal. Phase error is corrected by controlling the timing of the latch which passes data to the digital-to-analog converter.

Resolver excitation circuit

A circuit can be configured to process signals from either a resolver or an encoder to derive an indication of the sensed angular position. (1) When the circuit is configured for an encoder, the output from the encoder is periodically sampled. The phase relationship of the encoder input signals controls a counter. The output of the counter is periodically sampled to provide the position indication. (2) In the resolver configuration, the counter is rest at regular intervals. An apparatus detects zero crossings from the resolver signal and in response thereto samples the counter output to provide a measurement of the time interval between the counter reset and the zero crossing. The magnitude of the time interval corresponds to the phase angle of the resolver signal and hence to the angular position.

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Mayfield Heights, OH, United States of America

David J Morris