Resolver Interface Quadrant Detection via Phase Delay
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Solution Overview
Problem
Resolvers that use multiplexed signal sampling are unable to determine the position of an excitation coil beyond a 90° range without knowing the quadrant, as simultaneous sampling of signals is not possible, leading to ambiguity in position determination.
Innovation Solution
A resolver interface that includes a square wave generator, excitation counter, filter, excitation coil, secondary coils, and a sample circuit with a multiplexer and analog-digital converter, which determines the position by analyzing the magnitude and sign of secondary signals and calculating the excitation phase delay to identify the quadrant, allowing for accurate position calculation beyond 90°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiplexed signal sampling is used, then device complexity is reduced, but position measurement precision deteriorates beyond 90° range
Solution Approach 1:
The patent applies preliminary action by calculating the excitation phase delay in advance and using this pre-computed information to determine the quadrant. The phase delay calculation is performed before final position determination, allowing the system to resolve quadrant ambiguity without requiring simultaneous sampling of all signals.
Solution Approach 2:
The patent uses the excitation phase delay as an intermediary parameter to bridge the gap between multiplexed sampling limitations and accurate position measurement. This intermediate calculation enables the system to infer quadrant information that would otherwise be lost, allowing accurate position determination beyond 90° range despite sequential sampling.
2Measurement precision
If simultaneous signal sampling is used, then position determination accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple sampling circuits into a single multiplexed sampling circuit. Instead of requiring separate simultaneous sampling paths for the excitation signal and secondary signals, the system combines these into one sequential sampling mechanism that uses time-multiplexing to achieve the same measurement capability with reduced hardware complexity.
Solution Approach 2:
The patent employs periodic action through the multiplexed sampling approach, where signals are sampled in periodic cycles rather than simultaneously. The excitation signal and secondary signals are sampled in sequence within each period, and the phase delay calculation is performed over this periodic sampling pattern, enabling accurate position measurement without requiring complex simultaneous sampling hardware.
3Ease of operation
If multiplexed sampling is used, then ease of operation is improved, but information loss occurs in position determination
Solution Approach 1:
The patent implements feedback by using the calculated excitation phase delay to determine the quadrant, which then feeds back into the final position calculation. This feedback mechanism ensures that the quadrant information, which would otherwise be lost in multiplexed sampling, is recovered and used to correct the position determination, maintaining full information accuracy despite sequential sampling.
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 precise determination of resolver position beyond 90° by eliminating bias from different hardware elements and using the same sampling circuit for all signals, thereby accurately determining the quadrant and angle θ.
Implementation Method 1
An excitation signal supplied to the excitation coil generates corresponding output signals in the first and second secondary coils
Data Source
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AI summary
A resolver interface, 10, includes an excitation coil, 18, a first secondary coil, 20a, a second secondary coil, 20b, a sampling circuit, 21, and a controller, 28. The excitation coil, 18, receives an excitation signal that generates first and second signals in the first secondary coil, 20a, and the second secondary coil, 20b, respectively. The sampling circuit, 21, includes a multiplexer, 22, that samples at least one period of the excitation signal, 62, the first signal, and the second signal, individually. The controller 28, is configured to calculate a sign of the first signal and the second signal relative to the excitation signal, 62, wherein based on the calculated sign of the first signal and the second signal the controller determines a quadrant of the excitation coil, 18, and based on the determined quadrant and magnitudes of the sampled first signal and second signal calculates a position of the excitation coil, 18.