Transformerless Synchro-Resolver Demodulation for Shaft Angle Sensing
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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 transformerless method for demodulating synchro-resolver signals by convolving differential signals with sine waves to determine shaft angle, utilizing analog-to-digital converters and processors to calculate sine and cosine values from differential voltages, eliminating the need for bulky transformers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Scott-T transformers are used to convert three-phase output signals into two quadrature phase sinusoidal signals, then accurate shaft angle determination is achieved, but the device becomes bulky and heavy
Solution Approach 1:
The patent replaces the mechanical/electromagnetic transformer-based Scott-T circuit with a digital signal processing system. The three-phase signals are processed through analog-to-digital conversion and digital convolution with reference sine waves to generate quadrature signals, eliminating the need for physical transformers and reducing weight while maintaining measurement accuracy.
Solution Approach 2:
The patent creates digital copies of the input signals through analog-to-digital conversion and processes these copies through computational algorithms (convolution with reference waves) to generate the required quadrature outputs. This digital copying approach replaces the analog transformer-based signal conversion, reducing physical component size and weight.
2Measurement precision
If Scott-T transformers are used for signal conversion, then accurate shaft angle determination is achieved, but the device occupies excessive space
Solution Approach 1:
The patent replaces the physical Scott-T transformer circuit with a digital signal processing system using analog-to-digital converters and computational algorithms. This substitution eliminates bulky electromagnetic components and reduces the overall device footprint while maintaining the ability to accurately determine shaft angle.
Solution Approach 2:
The patent uses digital signal copying and processing to achieve the same functional result as the Scott-T transformers. By converting signals to digital form and processing them through computational convolution with reference waves, the system generates quadrature signals without requiring the physical space occupied by transformers.
3Reliability
If traditional transformer-based demodulation is used, then reliable signal conversion is achieved, but material requirements and manufacturing complexity increase
Solution Approach 1:
The patent replaces the complex assembly of transformer-based Scott-T circuits with simpler digital components: analog-to-digital converters, memory for reference waves, and computational processing. This substitution reduces manufacturing complexity while maintaining reliable signal conversion through well-defined digital algorithms.
Solution Approach 2:
The patent uses digital copying and processing of signals to achieve reliable conversion. Instead of assembling multiple transformer components, the system creates digital copies of input signals, processes them through standardized convolution algorithms with reference waves, and generates output signals. This approach simplifies manufacturing while ensuring consistent, reliable performance.
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 bulk and weight of traditional transformers, improving system compactness and reducing material requirements.
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
Implementation Method 2
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 is further configured to generate a first digitized sampling of the first voltage differential
Data Source
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. 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.