Baseband Resolver Signal Correction for Precise Rotor Position
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Solution Overview
Problem
Current resolver systems face inaccuracies in measuring rotor position due to noise, sampling delays, gain imbalances, and phase errors caused by non-ideal secondary winding spacing, leading to imprecision in computing angular position.
Innovation Solution
Implement high-speed sampling and demodulation of resolver output signals, followed by noise filtering and correction of delays and gain imbalances, to produce high-resolution representations of the signals, allowing for precise computation of rotor position and velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sampling is performed at AC peaks to simplify processing, then processing complexity is reduced, but measurement precision deteriorates due to noise, sampling delays, and gain imbalances
Solution Approach 1:
The patent applies preliminary action by performing demodulation and correction operations before final position computation. The system demodulates the secondary winding signals to extract amplitude information, then applies correction factors for gain imbalances and phase errors, and compensates for sampling delays before computing the arctangent to determine rotor position. This preliminary processing ensures high precision measurements while maintaining manageable complexity.
Solution Approach 2:
The patent implements feedback by using the demodulated signals from both secondary windings to compute correction factors for gain imbalances and phase errors. These correction factors are then applied back to the signals before final position computation. The system continuously monitors the signals and adjusts for errors through this feedback mechanism, improving measurement precision without significantly increasing processing complexity.
2Reliability
If secondary windings are spaced exactly 90° apart to produce ideal sine and cosine signals, then signal quality is improved, but manufacturing precision deteriorates due to difficulty in achieving exact spacing
Solution Approach 1:
The patent uses feedback to measure the actual phase difference between the two secondary windings and compute a phase correction factor. This correction factor is then applied to compensate for any deviation from the ideal 90° spacing. By continuously monitoring and correcting the phase relationship, the system maintains high signal quality without requiring extremely precise manufacturing of the winding spacing.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the phase correction factor based on the measured phase difference between secondary windings. Instead of relying on fixed mechanical precision, the system changes the electrical parameter (phase angle) through computational correction, allowing the system to compensate for manufacturing variations and maintain ideal signal quality.
3Measurement precision
If noise filtering and correction operations are applied to resolver output signals, then measurement precision is improved, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent applies preliminary action by performing demodulation, filtering, and correction operations in a structured sequence before final position computation. The system first demodulates the secondary signals to extract amplitude information, then applies low-pass filtering to remove high-frequency noise, followed by correction for gain imbalances and phase errors, and finally compensates for sampling delays. This organized preliminary processing improves measurement precision while keeping the overall system complexity manageable through systematic organization of operations.
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
This approach enhances the accuracy and precision of rotor position estimation by mitigating noise and correcting for sampling and phase errors, resulting in cleaner and more consistent signals compared to previous technologies.
Implementation Method 1
a resolver having an input primary and one or more output secondaries magnetically coupled to the input primary
Data Source
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AI summary
Monitoring rotating machine position using a resolver having an input primary and one or more output secondaries magnetically coupled to the input primary. The method includes exciting the input primary with an exciter input signal, causing a first scaled version of the exciter input signal to appear in a first output secondary. Output from the first output secondary is collected. The collected output from the first output secondary is demodulated to recover gain from the input primary.