Stator-Mounted Magnet Temperature Detection via Flux
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Solution Overview
Problem
In rotating electrical machines, accurately acquiring temperature information of permanent magnets is challenging due to their placement on the rotor, leading to potential demagnetization and the need for over-spec magnets, which complicates drive state control.
Innovation Solution
A magnet temperature information output device is positioned on the stator, using elements like temperature sensors and magnetic flux detectors to output electrical signals corresponding to the magnetic flux, allowing for accurate temperature monitoring of the rotor-mounted permanent magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is disposed on the rotor to detect the temperature of the permanent magnet, then temperature information can be acquired, but the temperature information tends not to be output appropriately and simply
Solution Approach 1:
The patent uses magnetic flux as an intermediary to indirectly measure permanent magnet temperature. Instead of directly reading temperature from a sensor on the rotor, the system measures changes in magnetic flux produced by the permanent magnet, which vary with temperature. This intermediary approach simplifies the output system while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces the mechanical/physical temperature sensor system with an electromagnetic measurement system. By using a coil to detect magnetic flux changes rather than a physical temperature sensor, the system achieves simpler output and integration with the existing electrical machine structure.
2Reliability
If an over-spec magnet with high heat resistance is selected, then demagnetization risk is reduced, but device complexity and cost increase
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors permanent magnet temperature through magnetic flux measurements. This real-time temperature information allows the control system to adjust operating parameters to prevent demagnetization, eliminating the need to select over-spec magnets with excessive heat resistance margins.
Solution Approach 2:
The patent transitions from a static approach (selecting magnets with fixed high heat resistance) to a dynamic approach (actively monitoring and controlling magnet temperature). This allows the system to adapt to varying operating conditions and maintain reliability without requiring permanently oversized magnet specifications.
3Ease of operation
If the permanent magnet is disposed on the rotor, then the rotating electrical machine structure is achieved, but temperature information tends not to be acquired accurately
Solution Approach 1:
The patent measures temperature indirectly through magnetic flux changes in the spatial dimension rather than direct thermal measurement. By placing a coil on the stator to detect the magnetic flux signature of the rotating permanent magnet, the system obtains temperature information without physical contact, maintaining operational simplicity while achieving accurate measurement.
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 configuration enables simple and appropriate output of temperature information, preventing demagnetization and allowing for controlled drive states that avoid overheating, thus extending the lifespan of the permanent magnets.
Implementation Method 1
an element arranged to detect a magnetic flux and output an electrical signal responding to the detected magnetic flux as the temperature information
Implementation Method 2
the temperature sensor is arranged such that an electrical resistance of the temperature sensor changes in response to the temperature of the permanent magnet
Implementation Method 3
the second coil is arranged to excite the first coil
Data Source
AI summary
A magnet temperature information output device is disposed on a rotating electrical machine including a stator and a rotor with a permanent magnet, and is arranged to output temperature information regarding a temperature of the permanent magnet. The magnet temperature information output device includes an element arranged to detect a magnetic flux and output an electrical signal responding to the detected magnetic flux as the temperature information. The element is disposed on the stator.