Resolver Monitoring via Oversampling Routine for Position Accuracy
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Solution Overview
Problem
Existing resolver systems face challenges in accurately monitoring rotational position and speed, especially at high rotational speeds, due to signal errors and faults that are difficult to detect efficiently.
Innovation Solution
The implementation of an oversampling routine that monitors and processes output signals from secondary windings of a resolver, determining demodulation angle errors and faults by analyzing parameters derived from these signals, allowing for precise position determination and fault detection across a range of rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sampling methods are used to monitor resolver output signals, then the monitoring system is simple and fast, but the measurement precision of rotational position and speed deteriorates at high rotational speeds
Solution Approach 1:
The patent segments the monitoring process into two distinct sampling rates: a first sampling rate for basic operational monitoring and a second, higher sampling rate for precise measurement at high rotational speeds. This segmentation allows the system to achieve high measurement precision when needed while maintaining simplicity during normal operation, resolving the contradiction between accuracy and complexity.
Solution Approach 2:
The system dynamically adjusts the sampling rate based on the rotational speed of the resolver. When the resolver operates at high speeds, the system automatically switches to the higher second sampling rate to maintain measurement precision. This dynamic adaptation allows the system to optimize between simplicity and precision according to operational conditions, resolving the contradiction effectively.
2Measurement precision
If oversampling is implemented to improve measurement precision, then the accuracy of rotational position and speed monitoring improves, but the processing time and computational load increase
Solution Approach 1:
The patent applies partial oversampling by implementing a second sampling rate that is higher than the first sampling rate but not excessively so. This partial oversampling provides sufficient measurement precision for high-speed operation while avoiding the excessive processing time that would result from much higher sampling rates. The principle resolves the contradiction by finding the optimal balance between precision improvement and time loss.
3Reliability
If traditional fault detection methods are used, then the system is simple and fast, but the reliability of fault detection deteriorates due to undetected signal errors
Solution Approach 1:
The patent segments fault detection into multiple levels: basic fault detection at the first sampling rate and enhanced fault detection at the second sampling rate. This segmentation allows the system to maintain simplicity for routine operation while providing reliable fault detection when needed, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The system implements feedback mechanisms where the higher sampling rate monitoring continuously checks for signal errors and faults, providing feedback to the control system. This feedback approach improves fault detection reliability by catching errors that would be missed by traditional methods, while the feedback structure manages complexity through systematic error checking and correction protocols.
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 of rotational position and speed monitoring, extends the operational range of resolver systems, and enables timely detection of faults, improving the reliability of electric machines.
Implementation Method 1
A resolver is an electromechanical transducer that includes a rotor having an excitation winding that is coupled to a rotatable member of a device, and a stator having secondary windings that are coupled to a non-rotating member of the device, wherein electromagnetic coupling between the primary winding and the secondary windings varies with the rotational position of the rotor
Implementation Method 2
In certain embodiments, the resolver is a variable reluctance resolver, in which an excitation winding is disposed in the stator, and an airgap between the rotor and the stator is modulated by the rotor, which modulates the transformation ratio depending on the rotational position
Data Source
AI summary
A resolver disposed to monitor a rotatable member is described, along with an associated method for evaluating an output signal therefrom. The method for monitoring the resolver includes supplying an excitation signal to the resolver, and monitoring, at an oversampling rate, first and second output signals from the resolver. An oversampling routine is executed to determine averages of the first and second output signals from the resolver. A demodulation angle error is determined based upon the first and second output signals from the resolver, and provided as feedback. A position of the resolver is also determined based upon the first and second output signals from the resolver.