Adaptive Resolver Envelope Diagnostic for Motor Control
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Solution Overview
Problem
Resolvers used in electric motors for direct field-oriented control can degrade over time, leading to faulty magnetic field control, making it difficult to accurately monitor and replace them when necessary.
Innovation Solution
A method and system that use adaptive sine and cosine envelopes from x-phase and y-phase voltages to determine an adaptive magnitude and rolling average, identifying faults by comparing the ratio of adaptive magnitude to the average against a threshold, with wobble compensation and processor-based diagnostics while the motor is operational.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resolver is used to monitor motor parameters for direct field-oriented control, then motor control accuracy is improved, but the resolver degrades or becomes damaged over time leading to faulty operation
Solution Approach 1:
The diagnostic system performs preliminary detection of resolver faults by continuously monitoring the magnitude of the resolver signal and comparing it to expected values. This allows early identification of degradation before complete failure occurs, enabling preventive maintenance while the motor is still operating normally.
Solution Approach 2:
The system implements feedback by continuously measuring the resolver signal magnitude, comparing it to a reference or historical values, and using this information to diagnose resolver health. The diagnostic algorithm provides feedback about resolver condition to the control system, allowing for adaptive monitoring and early fault detection.
2Loss of time
If the resolver is monitored continuously to detect faults early, then replacement timing is improved, but the diagnostic system complexity increases
Solution Approach 1:
The diagnostic system extracts only the magnitude information from the resolver signal for fault detection, rather than processing the complete signal. By focusing on the magnitude parameter and comparing it to reference values, the system achieves effective fault detection with minimal processing complexity, avoiding the need for complex analysis of all signal characteristics.
Solution Approach 2:
The resolver diagnostic functionality is integrated into the existing motor control system, allowing the control processor to perform diagnostic functions using its existing computational resources. The system serves itself by utilizing the same hardware and software infrastructure already present for motor control, eliminating the need for separate dedicated diagnostic hardware.
3Measurement precision
If wobble compensation is applied to the x-phase and y-phase voltages, then envelope accuracy is improved, but processing time increases
Solution Approach 1:
Wobble compensation is performed as a preliminary processing step before envelope detection. By pre-compensating the x-phase and y-phase voltages for wobble effects, the subsequent envelope extraction operates on already-corrected data, improving accuracy without requiring iterative or complex post-processing operations.
Solution Approach 2:
The wobble compensation replaces complex mechanical alignment issues with a computational correction approach. Instead of physically adjusting the resolver or motor alignment, the system uses digital signal processing to compensate for wobble effects, substituting mechanical precision requirements with algorithmic correction.
Data Source
AI summary
A diagnostic system for a resolve of a motor and a method of diagnosing the resolver. The diagnostic system includes an x-phase winding, a y-phase winding, and a processor. The x-phase winding generates an x-phase voltage and the y-phase winding generates a y-phase voltage. The processor obtains the x-phase voltage and the y-phase voltage, determines an adaptive cosine envelope from the x-phase voltage and an adaptive sine envelope from the y-phase voltage, determines an adaptive magnitude from the adaptive sine envelope and the adaptive cosine envelope, determines a magnitude average based on the adaptive magnitude, determines a fault of the resolver when a ratio of the adaptive magnitude and the magnitude average is greater than a threshold, and transmits a signal based on the fault.