Steering Motor Winding Fluid Detection via Parasitic Capacitance
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Solution Overview
Problem
Modern steering systems for transportation vehicles, especially those in fully automated states, face failures due to fluid ingress, such as water, which can penetrate through electric motors and cause control device or power electronic system failures.
Innovation Solution
A simplified sensor system utilizing existing windings and parasitic capacitance within the electric motor to detect fluid ingress by generating a test signal and measuring impedance changes, eliminating the need for a separate sensor element and providing redundancy through multiple sensor systems and evaluation units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate sensor element is used to detect fluid ingress, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the fluid detection function with the existing motor windings by utilizing their parasitic capacitance. The winding serves dual purposes: as an electrical component for motor operation and as a sensor element for fluid detection, eliminating the need for separate sensor elements and reducing overall device complexity while maintaining detection capability
Solution Approach 2:
The motor winding's inherent parasitic capacitance is utilized for fluid detection without requiring additional sensor components. The existing structural elements (windings) provide the sensing function themselves, making the system self-sufficient and reducing complexity
2Reliability
If multiple sensor systems are implemented for redundancy, then reliability is improved, but device complexity increases
Solution Approach 1:
The evaluation and control unit is designed to serve multiple windings simultaneously, performing both motor control and fluid detection functions across different windings. This multi-functional approach enables redundancy through multiple sensor systems while using a single shared evaluation unit, thereby improving reliability without proportionally increasing device complexity
3Measurement precision
If fluid detection sensitivity is enhanced, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The system performs fluid detection measurements before the start of a journey or operational cycle. By conducting preliminary checks when the motor is stationary and electrical conditions are stable, the system achieves high detection sensitivity without requiring extremely precise manufacturing tolerances, as the measurement conditions are optimized in advance
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
Enhances sensitivity and reliability in detecting fluid ingress, preventing system failures by generating warnings or preventing activation before the start of a journey, thus ensuring the steering system's operational integrity.
Implementation Method 1
the sensor element is formed by the at least one winding which is present in any case and a parasitic capacitance between the connection points, wherein a change in the capacitance is detected by ingressing fluid
Implementation Method 2
the test signal is an excitation frequency of an oscillatory circuit which is formed by the at least one winding and at least one parasitic capacitance between the connection points of the at least one winding under defined conditions
Implementation Method 3
an electric motor which applies at least part of the steering force. In the case of transportation vehicles which travel in a fully automated state, the steering system even provides the entire steering force
Data Source
AI summary
A drive part, in particular, a steering system for a transportation vehicle, having an electric motor and at least one control device, wherein the electric motor has at least one winding, wherein the winding has connection points for a power electronics system of the at least one control device, wherein the drive component has at least one sensor system for detecting fluid, wherein the sensor system has an evaluation and control unit connected to the connection points of the at least one winding, wherein the evaluation and control unit generates a test signal and detects a change in impedance.