Traction Drive Fuel Cell Pump Speed Reduction
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Solution Overview
Problem
Fuel cells face challenges in achieving high power density and efficiency due to the need for high rotational speeds in rotodynamic compressors, which are difficult for conventional devices to operate, necessitating a solution to drive these compressors effectively.
Innovation Solution
A speed-reduction traction drive system, such as a planetary or single roller traction drive, is used to interface with high-speed shafts of rotodynamic compressors, allowing a conventional electric motor to drive them at reduced rotational speeds, optionally assisted by turbines to extract power from exhaust gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rotodynamic compressor is used to pressurize air for the fuel cell, then power density and efficiency are improved, but the device requires high rotational speeds that are difficult for conventional devices to operate
Solution Approach 1:
A traction drive system is introduced as an intermediary between the conventional electric motor and the rotodynamic compressor. The traction drive includes a driven roller that interfaces with a high-speed shaft of the compressor, enabling speed multiplication while maintaining motor operation at conventional speeds. This mediator resolves the contradiction by decoupling the motor's operational speed from the compressor's required high speed.
Solution Approach 2:
The system changes the rotational speed parameter through the traction drive mechanism. The electric motor operates at a lower, conventional speed while the traction drive multiplies this speed to achieve the high rotational speeds required by the rotodynamic compressor. This parameter transformation allows the system to achieve high power density without requiring the motor itself to operate at difficult high speeds.
2Volume of moving object
If high rotational speeds are used in the rotodynamic compressor to increase power density, then the size and cost of the fuel cell are reduced, but conventional devices struggle to operate at these speeds
Solution Approach 1:
The traction drive serves as a mechanical intermediary that enables the coupling between a conventional-speed motor and a high-speed compressor. The driven roller with its specific diameter creates a speed multiplication effect, allowing the compressor to achieve the high rotational speeds needed for compact size while the motor operates at conventional, easily manageable speeds.
Solution Approach 2:
The system separates the speed dimension between the motor and compressor through the traction drive. The motor operates in a lower speed dimension while the traction drive transforms this to a higher speed dimension at the compressor, enabling compact fuel cell design without requiring the motor to operate at high speeds.
3Ease of operation
If a speed-reduction traction drive is used to interface with the high-speed shaft, then a conventional electric motor can drive the compressor, but the device complexity increases
Solution Approach 1:
The drive system is segmented into distinct functional components: the electric motor, the traction drive with driven roller, and the high-speed shaft connected to the compressor. This segmentation allows each component to be optimized independently - the motor for conventional operation and the traction drive for speed multiplication - while maintaining overall system manageability despite increased component count.
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 setup enables the efficient pressurization of air for fuel cells, increasing power density and reducing the size and cost of the fuel cell system while allowing standard electric motors to operate at high speeds required by rotodynamic compressors.
Implementation Method 1
a speed-reduction traction drive that interfaces with the high-speed shaft
Implementation Method 2
a rotodynamic compressor that pressurizes intake air for the fuel cell
Data Source
AI summary
Disclosed is an air pump for a fuel cell that utilizes a speed-reduction traction drive so that a low speed electric motor can be used to drive a high-speed rotodynamic compressor. The rotodynamic compressor is an efficient air pump, but operates at high speeds that would require a specialized high-speed electric motor. The speed-reduction traction drive couples to the compressor and provides a low-speed output that is connected to a lower speed electric motor.