Fuel Cell Air Supply Motor Demagnetization Control
Solution Overview
Problem
Fuel cell vehicles face output instability due to irreversible demagnetization of permanent magnets in the air supply device motor, leading to insufficient air supply and momentary drops in stack cell voltage, which hinder maintaining desired output during high power requirements.
Innovation Solution
An operation control system for fuel cell vehicles that includes a sensing unit to detect motor demagnetization, a calculation unit to determine the lower-limit voltage required for normal operation, and a controller to adjust the voltage supplied to the air supply device, utilizing an auxiliary power supply and charged amount measurement to ensure stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the air supply device motor operates at high power, then the fuel cell output is improved, but permanent magnet demagnetization occurs leading to performance degradation
Solution Approach 1:
The system performs preliminary detection of motor performance degradation through counter electromotive force constant monitoring before complete demagnetization occurs. By detecting changes in the counter electromotive force constant that indicate permanent magnet degradation, the system can take preventive actions such as limiting maximum motor speed or adjusting air supply device operation to prevent further demagnetization while maintaining acceptable fuel cell output.
Solution Approach 2:
The system continuously monitors the counter electromotive force constant of the air supply device motor and uses this feedback to detect performance degradation. When the constant deviates from expected values indicating demagnetization, the controller adjusts operating parameters such as motor speed limits or air supply rates to compensate for the degraded motor performance, thereby maintaining fuel cell output stability.
2Power
If the motor speed is increased to maintain fuel cell output, then the power output is improved, but air supply becomes insufficient due to demagnetization
Solution Approach 1:
The system dynamically adjusts the maximum motor speed of the air supply device based on the detected counter electromotive force constant. When demagnetization is detected (indicated by abnormal counter electromotive force constant values), the system reduces the maximum motor speed to a level that the degraded permanent magnets can sustain, preventing further performance degradation while maintaining adequate air supply for the fuel cell's power needs.
Solution Approach 2:
The system changes operational parameters including motor speed limits and air supply rates based on the detected motor performance status. When permanent magnet demagnetization is detected through counter electromotive force constant monitoring, the controller adjusts these parameters to ensure the air supply device operates within its reduced capability while maintaining fuel cell output stability.
3Measurement precision
If the counter electromotive force constant is monitored continuously, then the detection precision is improved, but the device complexity increases
Solution Approach 1:
The system uses the air supply device motor's own counter electromotive force characteristics as the sensing mechanism, eliminating the need for separate complex sensors. By measuring the counter electromotive force constant that naturally occurs during motor operation and comparing it against expected values, the system achieves accurate demagnetization detection using existing motor parameters and standard measurement capabilities.
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
The system effectively maintains fuel cell vehicle output by calculating and adjusting the lower-limit voltage, preventing insufficient air supply and voltage drops, thereby ensuring consistent performance even during abnormal operation of the air supply device.
Implementation Method 1
calculate a counter electromotive force constant based on the measured values
Data Source
AI summary
An operation control system and method of a fuel cell vehicle are provided. The system includes a fuel cell, an air supply device operated by a motor, to supply air to the fuel cell and a sensing unit that senses an abnormal operation of the air supply device. A calculation unit calculates a lower-limit voltage of the air supply device required for normal operation of the air supply device when the sensing unit senses abnormal operation of the air supply device. A controller then adjusts a voltage supplied to the air supply device based on the calculated lower-limit voltage.