Fuel Cell Air Compressor Motor Demagnetization Diagnosis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The air compressor motor in fuel cell vehicles experiences irreversible demagnetization, reducing its maximum driving speed and leading to insufficient air supply to the fuel cell stack, which can cause voltage drops and limit vehicle acceleration and performance.
Innovation Solution
A method to diagnose demagnetization of the permanent magnet in the air compressor motor by calculating the counter electromotive force constant and adjusting the motor current to maintain maximum drivable speed, thereby stabilizing vehicle operation by limiting the fuel cell stack current and ensuring adequate air supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the air compressor motor operates at high speed and high output, then the vehicle performance is improved, but the permanent magnet experiences irreversible demagnetization which reduces the maximum driving speed
Solution Approach 1:
The system performs preliminary diagnosis of permanent magnet demagnetization by calculating the counter electromotive force constant before operating the motor at high speed. This allows the control system to proactively identify demagnetization conditions and adjust operating parameters to prevent further magnet degradation while maintaining vehicle performance.
Solution Approach 2:
The system continuously monitors the counter electromotive force constant during motor operation and uses this feedback to detect changes in permanent magnet strength. Based on this feedback, the control system adjusts the motor's maximum allowable speed and output to compensate for demagnetization, ensuring reliable operation while maintaining optimal performance.
2Speed
If the permanent magnet is demagnetized, then the maximum driving speed of the air compressor motor is reduced, but the vehicle operation stability deteriorates due to insufficient air supply
Solution Approach 1:
The system calculates the counter electromotive force constant in advance during normal operation to establish a baseline for permanent magnet strength. When demagnetization is detected, the system proactively adjusts the maximum driving speed limit before stability issues occur, preventing insufficient air supply and maintaining vehicle operation stability.
Solution Approach 2:
The system changes the operating parameters of the air compressor motor based on the diagnosed demagnetization level. By adjusting the maximum driving speed limit according to the counter electromotive force constant, the system optimizes the balance between motor speed capability and air supply requirements, maintaining stable vehicle operation despite magnet degradation.
3Speed
If the motor driving speed is reduced due to demagnetization, then the air supply to the fuel cell stack becomes insufficient, but the voltage of the cell instantaneously decreases triggering current limitation
Solution Approach 1:
The system uses feedback from the counter electromotive force constant calculation to continuously monitor permanent magnet health. When demagnetization is detected, the control system adjusts the motor's maximum speed limit to ensure adequate air supply to the fuel cell stack, preventing voltage drops and the need for current limitation that would otherwise occur.
Solution Approach 2:
The system dynamically changes the motor operating parameters based on the diagnosed demagnetization level. By adjusting the maximum driving speed to match the reduced magnetic flux capability, the system maintains sufficient air flow to the fuel cell stack, preventing instantaneous voltage decreases and preserving power output stability.
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 improves driving stability by proactively adjusting the air compressor motor's operation based on demagnetization, preventing voltage drops and reducing issues like vehicle rattling, while maintaining the fuel cell stack's output within safe limits.
Implementation Method 1
calculating a counter electromotive force constant of the air compressor motor based on a voltage and a current of the air compressor motor and a rotation speed of the air compressor motor
Data Source
AI summary
A method of controlling an air compressor motor for a fuel cell vehicle is provide. The method includes calculating a counter electromotive force constant of the air compressor motor based on a voltage and a current of the air compressor motor for the fuel cell vehicle supplying air to a fuel cell stack and a rotation speed of the air compressor motor. The method additionally includes determining whether a permanent magnet of the air compressor motor is demagnetized based on a result of comparison between the calculated counter electromotive force constant value and a pre-set counter electromotive force constant design value.