Resolver Angle Conversion Without Excitation Signal Demodulation
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Solution Overview
Problem
Conventional resolver-to-digital converters require an excitation signal for demodulation, which can be unavailable, leading to complexity and expense in design and production.
Innovation Solution
A resolver converter that determines the angular position of a rotor without an excitation signal by using zero-crossing points to apply a sign to processed signals, eliminating the need for demodulation and excitation signal provision or regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional demodulation method is used, then accurate angular position measurement is achieved, but excitation signal is required which increases device complexity and cost
Solution Approach 1:
The patent extracts and eliminates the demodulation step from the conventional resolver-to-digital conversion process. By using zero-crossing detection of the secondary winding signals directly, the system removes the need for excitation signal regeneration and complex demodulation circuitry, while still achieving accurate angular position measurement through the relationship between zero-crossing points and rotor angle.
Solution Approach 2:
The system uses the secondary winding signals themselves to determine the angular position through zero-crossing detection, without requiring external excitation signal provision or internal signal regeneration. The resolver converter processes the available secondary signals directly, making the system self-sufficient and eliminating additional signal generation components.
2Loss of information
If excitation signal is provided for demodulation, then digital indication of angular position is obtained, but cost and design complexity increase
Solution Approach 1:
The patent removes the excitation signal provision and demodulation stages from the manufacturing process. By directly processing secondary winding signals through zero-crossing detection and arithmetic operations, the system simplifies the manufacturing process while maintaining the ability to extract accurate angular position information.
Solution Approach 2:
The patent replaces expensive and complex demodulation circuitry with simpler, more cost-effective components such as zero-crossing detectors, multipliers, and adders. This substitution reduces production costs and simplifies manufacturing while achieving the same functional outcome of digital angular position indication.
3Measurement precision
If demodulation is performed, then accurate rotor angle estimation is achieved, but system requires excitation signal which is may be unavailable
Solution Approach 1:
The resolver converter uses the secondary winding signals directly to determine rotor angle through zero-crossing detection, without requiring the excitation signal to be available. The system processes the available secondary signals through arithmetic operations (multiplication and addition) to achieve accurate angle estimation, making it adaptable to situations where excitation signal is unavailable.
Solution Approach 2:
Instead of using the excitation signal to drive demodulation as in conventional systems, the patent inverts the approach by using the secondary winding signals themselves as the basis for angle determination. This inversion allows operation without the excitation signal while maintaining measurement accuracy through mathematical processing of the secondary signals.
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 digital indication of angular position without the need for an excitation signal, simplifying design and reducing costs by using a method that updates the estimated rotor angle through error measurement and sign toggling based on zero-crossing detection.
Implementation Method 1
Two or more secondary windings are located near the primary winding with intersecting positions and/or orientations, and are electromagnetically coupled to the primary winding, as in a transformer. The coupling factor to each secondary winding is dependent upon the angular orientation of the primary winding, which changes as the primary winding rotates.
Data Source
AI summary
A resolver to digital converter is provided and includes first and second inputs to receive signals from a resolver and an output to provide an estimated angle of a rotor. The sine component signal is multiplied by the cosine of the estimated angle and the cosine component signal is multiplied by the sine of the estimated angle, and a difference between them is calculated to provide an error measurement. The estimated angle is updated by the error measurement.