Resolver Defect Detection via RC Circuit Oscillation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resolvers struggle to reliably detect short circuits and other defects, especially at angular positions where the signal is 0V, making it difficult to differentiate between a short circuit and an intact resolver.
Innovation Solution
The apparatus connects the receiver winding to both positive and negative voltage sources through RC circuits with actuable switches, monitoring the oscillation behavior to detect defects, using transistors for precise switching and a control unit to evaluate the voltage profiles for each winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotor is located at angular positions of 0° or 180°, then the first receiver winding produces a voltage of 0V, but a short circuit bypassing the first receiver winding cannot be detected
Solution Approach 1:
The system performs preliminary diagnostic actions by connecting voltage sources through RC circuits to the receiver windings before normal operation to detect defects. The control unit actuates switches to connect positive and negative voltage sources to the first receiver winding through first and second RC circuits, respectively, enabling oscillation behavior monitoring that can detect short circuits even when the rotor is at positions where the normal signal would be 0V.
Solution Approach 2:
The system uses electrical oscillation (analogous to mechanical vibration) by creating an oscillating circuit through the RC circuits and receiver winding. The control unit monitors the oscillation behavior of the receiver winding to detect defects - a short circuit changes the oscillation characteristics, allowing reliable defect detection independent of rotor angular position.
2Adaptability or versatility
If the excitation winding is disposed on the rotor to rotate with it, then angular position detection is enabled, but short circuits in windings cannot be distinguished from intact resolver at certain positions
Solution Approach 1:
The diagnostic system performs preliminary testing by actuating switches to connect voltage sources to receiver windings before or separate from normal operation. This preliminary action enables defect detection without being influenced by the rotor's angular position during normal resolver operation.
Solution Approach 2:
The RC circuits and switches serve as intermediary components between the voltage sources and receiver windings. These intermediaries enable the control unit to actively test the receiver windings by controlling the connection of voltage sources, thereby detecting defects independently of the rotor position that would otherwise affect the signal.
3Productivity
If the receiver windings are excited by sinusoidal AC voltage, then angular position information is generated, but defects cannot be detected when received signal is 0V
Solution Approach 1:
The control unit periodically actuates the switches to connect and disconnect voltage sources through RC circuits to the receiver windings. This periodic diagnostic action occurs independently of the continuous sinusoidal excitation, creating opportunities to monitor oscillation behavior and detect defects at intervals regardless of the rotor's instantaneous angular position.
Solution Approach 2:
The system performs preliminary diagnostic checks by actively connecting voltage sources through RC circuits before relying on the normal sinusoidal excitation signal. This preliminary action enables the detection of defects that would otherwise be undetectable when the sinusoidal signal happens to be at 0V.
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
Enables reliable and unambiguous detection of defects in resolvers at all angular positions, including where the signal is 0V, by analyzing the oscillation behavior and voltage profiles, effectively distinguishing between short circuits and interruptions.
Implementation Method 1
an oscillating circuit is activated, in which the energy stored in the receiver winding is brought into oscillation
Implementation Method 2
the exciter winding generates a magnetic field in the rotor by means of induction, which in turn induces a voltage in the receiver windings
Data Source
AI summary
An apparatus for operating a resolver which includes at least one first receiver winding and an exciter winding, which are/can be associated with a rotor, and an evaluation device which determines an angular position of the rotor as a function of an induced voltage that is generated by the exciter winding and detected by the receiver winding. According to the invention, the first receiver winding is connected at a first end to an actuable switch by means of a first RC circuit, said switch connecting the RC circuit as required to a positive voltage source, and the first receiver winding is connected at a second end to a second actuable switch by means of a second RC circuit, said second switch connecting the second RC circuit as required to a negative voltage source, and to a control unit which simultaneously actuates the switches as required.