Transformerless demodulation of synchro-resolver
AssigneeHamilton Sundstrand Corporation
InventorJohn O'Neil
Life of this patent
Estimating the term…
Abstract
Apparatus and associated methods relate to a transformer-less way of demodulating signals generated by a synchro-resolver so as to determine a shaft angle of the synchro-resolver. A first differential output voltage between a first pair of the wye-configured secondary windings is used to generate a first output. A second differential output voltage between a second pair of the wye-configured secondary windings, different from the first pair, is used to generate a second output. The first and second outputs are combined to form a signal quadrature to the first output. The first output and the signal quadrature thereto are used to determine the shaft angle.
Claims20
A method for generating a signal indicative of a shaft angle of a synchro-resolver, the method comprising:
- convolving a first differential signal induced between a first output terminal and a second output terminal of a three-phase secondary winding of the synchro-resolver with a first sine wave having a period and a phase equal to a period and phase of the first differential signal, thereby generating a first convolution result;
- determining a magnitude of the first differential signal based on the first convolution result;
- using the magnitude of the first differential signal as a measure of a sine of the shaft angle;
- convolving a second differential signal induced between the first output terminal and a third output terminal of a three-phase secondary winding of the synchro-resolver with a second sine wave having a period and a phase equal to a period and phase of the second differential signal, thereby generating a second convolution result;
- determining a magnitude of the second differential signal based on the second convolution result;
- creating a measure of a cosine of the shaft angle based on a weighted sum of the measures of the magnitudes of the first and second differential signals;
- and
- determining the shaft angle based on the measures of the sine and cosine of the shaft angle.
A synchro-demodulator for generating a signal indicative of a shaft angle of a three-phase synchro-resolver, the synchro-demodulator comprising:
- a first analog-to-digital (A/D) converter that receives a first voltage differential between a first output terminal of first secondary windings of the three-phase synchronous resolver and a second output terminal of second secondary windings of the three-phase synchro-resolver, the first A/D converter further configured to generate a first digitized sampling of the first voltage differential;
- a second A/D converter that receives a second voltage differential between the first output terminal of first secondary windings of the three-phase synchronous resolver and a third output terminal of third secondary windings of the three-phase synchro-resolver, the second A/D converter further configured to generate a second digitized sampling of the second voltage differential;
- a processor configured to receive the first and second digitized samplings;
- and
- computer readable memory containing instructions that, when executed by the processor cause the synchro-demodulator to:
- convolve a first differential signal induced between a first output terminal and a second output terminal of a three-phase secondary winding of the synchro-resolver with a first sine wave having a period and a phase equal to a period and phase of the first differential signal, thereby generating a first convolution result;
- determine a magnitude of the first differential signal based on the first convolution result;
- use the magnitude of the first differential signal as a measure of a sine of the shaft angle;
- convolve a second differential signal induced between the first output terminal and a third output terminal of a three-phase secondary winding of the synchro-resolver with a second sine wave having a period and a phase equal to a period and phase of the second differential signal, thereby generating a second convolution result;
- determine a magnitude of the second differential signal based on the second convolution result;
- create a measure of a cosine of the shaft angle based on a weighted sum of the measures of the magnitudes of the first and second differential signals;
- and
- determine the shaft angle based on the measures of the sine and cosine of the shaft angle.
Dependencies are inferred from the claim text.