Fuel Cell Compressor Control via Delayed Valve Feedback
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Solution Overview
Problem
The existing fuel cell system experiences hunting of the flow rate and pressure of the cathode gas due to simultaneous feedback control of the compressor torque and pressure regulation valve opening position.
Innovation Solution
A fuel cell system with a controller that calculates torque and opening position target values based on flow rate and pressure targets, and uses delayed feedback to control the compressor and pressure regulation valve, suppressing hunting by delaying the opening position feedback of the pressure regulation valve relative to the compressor torque feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If simultaneous feedback control of compressor torque and pressure regulation valve opening position is implemented, then control responsiveness is improved, but hunting of flow rate and pressure occurs
Solution Approach 1:
The control method delays the feedback signal of the pressure regulation valve opening position relative to the compressor torque feedback signal. This temporal sequencing ensures that the pressure regulation valve responds after the compressor has already adjusted, preventing simultaneous opposing actions that cause hunting. The delay is implemented through a delay element in the feedback path, allowing the system to establish primary pressure control before secondary flow regulation kicks in.
2Stability of the object's composition
If feedback control of pressure regulation valve opening position is delayed, then hunting is suppressed, but control accuracy may deteriorate
Solution Approach 1:
The system maintains feedback control for the pressure regulation valve despite the delay, using the delayed feedback signal to continuously adjust the valve opening position. The feedback loop ensures that the valve eventually reaches the correct position, compensating for the initial delay. This approach balances stability (through delayed feedback) with accuracy (through continuous correction).
Data Source
AI summary
A fuel cell system comprises a controller configured to: (i) calculate a torque target value of a compressor and an opening position target value of a pressure regulation valve from a flow rate target value of a cathode gas and a pressure target value of a cathode gas flow path, the flow rate target value of the cathode gas and the pressure target value being determined according to a required power output of a fuel cell stack; (ii) calculate a torque feedback value of the compressor from a difference between a flow rate measurement value and the flow rate target value of the cathode gas, and control the compressor using a torque command value obtained by adding the torque target value and the torque feedback value; and (iii) calculate an opening position feedback value of the pressure regulation valve from a difference between a pressure measurement value and the pressure target value of the cathode gas flow path, and control an opening position of the pressure regulation valve using an opening position command value obtained by adding the opening position target value of the pressure regulation valve and a delayed opening position feedback value that is obtained by delaying the opening position feedback value. This configuration suppresses the hunting of the flow rate and the pressure.