Wiegand Wire Sensor for Electric Power Steering Motor Position Monitoring
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Solution Overview
Problem
The active sensor in vehicle electric power steering assemblies consumes unnecessary electrical power when monitoring the electric motor's position even when the motor is not turning, leading to increased energy consumption.
Innovation Solution
A magnet is fixed to the output shaft of the motor, generating a rotating magnetic field that activates a passive sensor using a Wiegand wire, which in turn activates the active sensor only when the motor is rotating, allowing it to detect the motor's position efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the active sensor continuously monitors the motor position, then the position detection accuracy is maintained, but the electrical power consumption increases
Solution Approach 1:
The active sensor operates in periodic intervals rather than continuously. The controller activates the active sensor only when the motor is determined to be rotating, based on signals from the passive sensor. This periodic operation maintains position detection accuracy when needed while significantly reducing electrical power consumption during idle periods.
Solution Approach 2:
The passive sensor continuously generates voltage pulses in response to the rotating magnetic field without requiring external power. These pulses automatically trigger the controller to activate the active sensor only when rotation is detected, creating a self-regulating system that balances measurement precision with energy efficiency.
2Use of energy by moving object
If the active sensor is activated only when the motor is rotating, then the electrical power consumption is reduced, but the position monitoring capability is compromised when the motor is stationary
Solution Approach 1:
The passive sensor acts as an intermediary that continuously monitors the magnetic field generated by the motor shaft. When the motor is stationary, the passive sensor produces no voltage pulses, and the active sensor remains inactive. When the motor rotates, the passive sensor generates pulses that trigger the active sensor. This intermediary mechanism ensures the active sensor is activated only when position monitoring is actually needed, maintaining reliability while reducing power consumption.
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 solution reduces electrical power consumption by activating the active sensor only when the motor is turning, thereby minimizing unnecessary power usage.
Implementation Method 1
A magnet is fixed to an output shaft of the motor and emits a magnetic field. The magnetic field rotates when the motor rotates.
Implementation Method 2
The passive sensor has a Wiegand wire that generates a voltage pulse in response to rotation of the magnetic field.
Implementation Method 3
The active sensor may be a Hall effect sensor or a giant magnetoresistance (GMR) sensor.
Implementation Method 4
The active sensor may be a Hall effect sensor or a giant magnetoresistance (GMR) sensor.
Data Source
AI summary
A magnet is fixed to an output shaft of a motor. The output shaft is rotated such that a magnetic field emitted by the magnet also rotates. A voltage pulse is generated from a passive sensor when the magnetic field rotates past the passive sensor. The voltage pulse is generated using a Wiegand wire. An active sensor is activated, from an unpowered state, in response to the voltage pulse. The active sensor detects a position of the magnet that correlates to a position of the output shaft.