Resolver Exciter Line Short Circuit Detection Method
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Solution Overview
Problem
Existing methods for diagnosing a short in a resolver excitation line to ground or operating voltage are inadequate as they cannot distinguish between a short and other faults, such as an open excitation line, due to the absence of sine and cosine signals.
Innovation Solution
A method involving continuous measurement of excitation voltage amplitude and voltage profiling of individual excitation lines referenced to ground, with threshold-based analysis to identify shorts and determine the affected line's potential, utilizing AD converters and electronic switches to facilitate rapid and precise fault diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the two receiver signals (sine and cosine) are monitored for fault diagnosis, then the presence of a short can be detected, but the specific location and nature of the fault cannot be identified
Solution Approach 1:
The patent segments the fault diagnosis process into multiple measurement stages: first measuring the excitation voltage to detect amplitude anomalies, then measuring individual excitation line voltages to locate the specific line and potential involved. This segmentation transforms a single undifferentiated detection into multiple targeted measurements that progressively narrow down the fault location.
Solution Approach 2:
The patent adds a new measurement dimension by introducing a third voltage measurement (excitation line voltage referenced to ground) in addition to the existing two receiver signals. This third dimension of measurement provides the additional information needed to distinguish between different fault types and locations, enabling precise fault identification.
2Measurement precision
If additional measurement circuits are added to precisely locate faults, then fault identification accuracy improves, but device complexity increases
Solution Approach 1:
The patent makes the existing AD converter multi-functional by using it for different measurement purposes at different times. The same hardware resource is reused to measure excitation voltage, excitation line voltage, and potentially other parameters, eliminating the need for separate dedicated measurement circuits for each function.
Solution Approach 2:
The patent implements periodic switching between different measurement modes: during normal operation, receiver signals are monitored; when a fault is suspected, the system periodically switches to measure excitation voltage and excitation line voltage. This periodic action allows comprehensive fault diagnosis using the same hardware at different times rather than requiring all measurements to occur simultaneously.
3Reliability
If continuous monitoring of excitation voltage is performed, then short circuits can be detected early, but energy consumption increases
Solution Approach 1:
The patent implements periodic sampling of the excitation voltage at multiple time points during each excitation period rather than continuous monitoring. This approach captures the voltage profile over time to detect amplitude anomalies while consuming significantly less energy than true continuous monitoring would require.
Solution Approach 2:
The patent performs preliminary measurements of the excitation voltage characteristics during normal operation to establish a baseline. When a fault is suspected, additional measurements are triggered. This preliminary action allows the system to detect faults early without requiring constant high-energy monitoring.
Data Source
AI summary
A method for detecting a short circuit (10) of a resolver exciter line (11, 12) comprising the steps of:measuring (31) the excitation voltage (U(ti) for the resolver (16) at a number of points in time during each excitation period;determining (32) the amplitude of the excitation voltage;starting a diagnostic mode (33) having the following steps (34 bis 37) if the amplitude of the excitation voltage does not reach a first threshold value;retrieving (34) the time-dependent voltage curves UH (ti) of the first and the second exciter line (H; 11) with respect to ground at the number of points in time;calculating (35) the amplitudes and the offset values of the time-dependent voltage curves;identifying (36) the exciter line that has a short circuit by determining that the calculated amplitudes do not exceed a second threshold value;identifying (37) the potential to which the short-circuited line (H or L) can be connected by comparing the offset values to third threshold values.