Synchro-Resolver Demodulation Without Scott-T Transformers
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Solution Overview
Problem
Synchro-demodulators using Scott-T transformers are bulky and heavy, making them unsuitable for applications requiring compact designs.
Innovation Solution
A method and apparatus for transformerless demodulation of synchro-resolvers that utilize differential signals from three-phase secondary windings to determine shaft angle, employing analog-to-digital converters and processors to calculate sine and cosine values from these signals, eliminating the need for bulky transformers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Scott-T transformer is used to convert three-phase output signals into two quadrature phase sinusoidal signals, then the shaft angle can be determined accurately, but the synchro-demodulator becomes bulky and heavy
Solution Approach 1:
The patent extracts and eliminates the Scott-T transformer from the synchro-demodulator circuitry. Instead of using the transformer to convert three-phase signals to quadrature signals, the invention directly processes the three-phase secondary winding outputs through analog-to-digital converters and digital signal processing to determine shaft angle, removing the bulky transformer component entirely
Solution Approach 2:
The patent replaces the electromagnetic transformation mechanism (Scott-T transformer) with a digital processing system. The three-phase signals are converted to digital form and processed algorithmically to compute shaft angle, substituting physical electromagnetic components with computational methods that have negligible weight
2Measurement precision
If a Scott-T transformer is used to convert three-phase output signals into two quadrature phase sinusoidal signals, then the shaft angle can be determined accurately, but the synchro-demodulator volume increases
Solution Approach 1:
The patent extracts and eliminates the Scott-T transformer from the synchro-demodulator circuitry. Instead of using the transformer to convert three-phase signals to quadrature signals, the invention directly processes the three-phase secondary winding outputs through analog-to-digital converters and digital signal processing to determine shaft angle, removing the bulky transformer component entirely
Solution Approach 2:
The patent replaces the electromagnetic transformation mechanism (Scott-T transformer) with a digital processing system. The three-phase signals are converted to digital form and processed algorithmically to compute shaft angle, substituting physical electromagnetic components with computational methods that have negligible volume
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables compact and efficient determination of shaft angle without the use of bulky transformers, improving system compactness and reducing weight.
Implementation Method 1
The primary winding is excited by an alternating current, which electromagnetically induces voltages in each of the three wye-configured secondary windings
Data Source
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AI summary
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 (22). 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.