Fuel Cell Air Compressor Motor Control Under Overcurrent Anomalies
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Solution Overview
Problem
Induction motors in air compressors of fuel cell systems experience overcurrent issues during high-speed operation, leading to anomalies in determining rotor position, which can cause the motor to stop unexpectedly.
Innovation Solution
A method to control the motor's driving based on an expected rotational speed derived from air flow rate and pressure values, using a rotational speed map, to manage overcurrent situations and maintain motor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor is controlled at high rotational speed for high output, then the power output is improved, but overcurrent occurs causing anomaly in determining rotor position
Solution Approach 1:
The system performs preliminary action by determining the expected rotational speed based on air flow rate and air pressure before the overcurrent anomaly disrupts rotor position determination. This pre-calculated expected speed is stored and used as a reference when anomalies occur, allowing the system to maintain reliable control without stopping the motor.
Solution Approach 2:
The expected rotational speed acts as an intermediary between the speed command and the actual motor control. When overcurrent occurs and rotor position determination fails, the controller uses this intermediary expected speed value to continue controlling the motor driving, thereby maintaining reliability without sacrificing power output.
2Device complexity
If sensorless control scheme is used to reduce component count, then device complexity is reduced, but rotor position determination becomes unreliable under overcurrent conditions
Solution Approach 1:
The system uses self-service by leveraging readily available sensor data (air flow rate and air pressure sensors already present in the fuel cell system) to calculate the expected rotational speed. This eliminates the need for additional sensors or complex position determination mechanisms, maintaining low device complexity while improving reliability through the use of existing system resources.
Solution Approach 2:
The system implements feedback by continuously monitoring air flow rate and air pressure to determine the expected rotational speed. This feedback mechanism provides a reliable reference value that compensates for the unreliability of sensorless control under overcurrent conditions, allowing the system to maintain accurate motor control without adding physical sensors.
3Reliability
If motor control stops when anomaly occurs, then reliability is protected, but continuous operation cannot be maintained
Solution Approach 1:
The system performs preliminary action by calculating and storing the expected rotational speed before anomalies occur. This pre-prepared reference value allows the controller to immediately switch to using the expected speed when overcurrent occurs, maintaining both reliability and continuous operation without interruption to the fuel cell system.
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
Enables continuous control of the motor's rotational speed even when overcurrent occurs, preventing motor shutdown and ensuring stable operation of the air compressor.
Implementation Method 1
an air compressor including a motor such that introduced air is compressed and supplied to the fuel cell stack
Data Source
AI summary
A driving control method for a motor of an air compressor is provided and includes: controlling driving of the motor based on a speed command for the motor of the air compressor and a current rotational speed of the motor; and controlling driving of the motor based on the speed command and an expected rotational speed of the motor when an anomaly occurs in determining the current rotational speed. In particular, the expected rotational speed is determined based on a rotational speed map regarding the motor, an air flow rate sensing value and an air pressure sensing value.