Resolver Isolation Failure Detection Circuit
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Solution Overview
Problem
Existing failure detecting apparatuses for signal detection systems, particularly resolvers, face challenges in accurately diagnosing isolation failures due to limited flexibility in setting threshold values, which affects noise tolerance and detection accuracy.
Innovation Solution
A failure detecting apparatus that applies DC voltage to primary and secondary coils to set different DC potentials, using differential signal generating means such as inverting or non-inverting amplifier circuits to amplify or reduce differential signals, allowing for flexible threshold setting and enhanced detection of isolation failures between coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DC voltage is applied to coils to set different DC potentials for isolation failure detection, then detection accuracy is improved, but device complexity increases due to additional voltage applying means and differential signal generating means
Solution Approach 1:
The DC voltage applying means is designed to apply DC voltage to multiple different coils independently, allowing the same circuit structure to serve multiple detection purposes for different coil combinations (primary-secondary, secondary-secondary), thereby reducing overall system complexity through functional reuse
Solution Approach 2:
The detection system is divided into independent detection channels, each with its own voltage applying means and differential signal generating means. Each channel independently monitors specific coil isolations, allowing modular design and simplifying the overall complex system through structured segmentation
2Reliability
If threshold value is set based on bias voltage to determine isolation failure, then detection capability is achieved, but adaptability deteriorates because threshold setting becomes rigid and noise tolerance degrades
Solution Approach 1:
The system dynamically adjusts the threshold value based on the actual bias voltage detected in each coil, rather than using a fixed threshold. This allows the detection system to adapt to different operating conditions and voltage levels, improving both reliability and adaptability simultaneously
Solution Approach 2:
The differential signal generating means uses feedback from the actual voltage potentials of the coils to dynamically set appropriate threshold values. The system continuously monitors the bias voltages and adjusts the isolation failure threshold accordingly, enabling adaptive detection that maintains high reliability while being flexible to changing conditions
3Adaptability or versatility
If DC voltage is applied to multiple coils to enable flexible threshold setting, then adaptability is improved, but measurement precision may deteriorate due to increased noise sensitivity
Solution Approach 1:
The system applies DC voltage to establish defined DC potentials for each coil, creating stable reference potentials that reduce voltage fluctuations and noise. By establishing equipotential references through the voltage applying means, the system achieves both adaptability in threshold setting and improved noise tolerance
Solution Approach 2:
The differential signal generating means acts as an intermediary that processes the voltage signals from multiple coils, extracting the differential component that represents isolation failure while canceling out common-mode noise. This intermediary function enables flexible threshold setting while maintaining measurement precision by filtering out noise
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 enables accurate detection of isolation failures by quantifying changes in DC potentials, improving noise tolerance and detection accuracy, and allowing for flexible threshold settings, even in systems with multiple coils.
Implementation Method 1
a magnetic flux is generated by an AC excitation current applied to the primary coil that rotates with the rotor whereby voltage is induced at the secondary coil
Implementation Method 2
voltage applying means for applying a DC voltage to at least one coil of the signal detection apparatus so as to set a DC potential of the at least one coil is different from any one of DC potential of coils
Implementation Method 3
differential signal generating means for generating a differential signal which is an amplified signal of the difference between the voltage at the at least one coil and a predetermined voltage
Data Source
AI summary
A failure detecting apparatus that detects an isolation failure between a plurality of coils included in a signal detection apparatus. The failure detecting apparatus includes a voltage applying unit that applies a DC voltage to a coil in the plurality of coils; a differential signal generating unit that generates a differential signal from a voltage at the coil and a predetermined voltage; a threshold voltage setting circuit that outputs a threshold voltage; and a comparator that compares the differential signal with the threshold voltage, thereby detecting whether or not an isolation failure exists. The differential signal generating unit includes either first setting unit for setting an absolute value of the differential signal to be amplified with a predetermined gain or second setting unit for setting the predetermined voltage to be different from a ground potential, and the predetermined gain is set to a value different from one and zero.