Resolver Circuit Diagnostic Device Using Signal Level Shifting
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Solution Overview
Problem
Conventional diagnostic devices for resolver circuits fail to accurately detect abnormalities in the amplitude of excitation signals, leading to inaccurate diagnosis of the soundness of the resolver circuit.
Innovation Solution
A diagnostic device that includes a shifter to level-shift excitation signals and a trigger generation circuit to detect abnormalities based on the shifted signals, allowing for precise diagnosis of resolver circuit soundness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If zero crossing points of excitation signal are used for diagnosis, then abnormalities in resolver output signals can be detected, but abnormalities in amplitude of excitation signal cannot be detected
Solution Approach 1:
The shifter performs preliminary level-shifting of the excitation signals before they reach the trigger generation circuit. By adjusting the baseline level of the excitation signals in advance, the system enables the trigger circuit to detect amplitude abnormalities that would otherwise be invisible to zero-crossing-based diagnosis methods.
Solution Approach 2:
The shifter acts as an intermediary component between the excitation signal source and the trigger generation circuit. It modifies the signal characteristics (level-shifting) to make the signal suitable for amplitude-based diagnosis, thereby enabling the trigger circuit to function as an effective diagnostic tool for amplitude abnormalities.
2Measurement precision
If conventional diagnostic methods are used, then the device structure remains simple, but diagnosis accuracy is insufficient
Solution Approach 1:
The shifter serves as an intermediary component that bridges the gap between simple conventional diagnostic methods and accurate amplitude-based diagnosis. By inserting this single level-shifting stage, the system achieves comprehensive diagnosis capability without substantially increasing overall device complexity.
Solution Approach 2:
The shifter changes the parameter (signal level) of the excitation signal to enable effective diagnosis. By adjusting the DC offset or baseline level of the signal, the system transforms the signal into a form that allows the trigger generation circuit to detect amplitude abnormalities, thereby improving diagnosis accuracy with minimal structural addition.
Data Source
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AI summary
A diagnostic device capable of accurately diagnosing the soundness of a resolver circuit is provided. A shifter (101) receives excitation signal (EXC+) and excitation signal (EXC-); shifts the level of excitation signal (EXC+), excitation signal (EXC-), or both; and performs level shifting such that a period of time (ΔT) that starts with one of two times in which, in the vicinity of the peak value of excitation signal (EXC+), excitation signal (EXC+) and excitation signal (EXC-) are at the same value and ends with the other of the two times is less than a prescribed threshold. A trigger generation circuit (102) generates a trigger (Trg) during said period of time (ΔT). A control unit (103) determines whether there is an abnormality in the resolver circuit on the basis of the trigger (Trg).