Fuel Cell Stack Discharge Through Traction Motor Stator Windings
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Solution Overview
Problem
Existing systems for discharging residual energy from hydrogen fuel cells are bulkier and prone to failures due to the use of multiple electromechanical components, which can lead to high repair costs and are often dedicated only to this function.
Innovation Solution
A method that utilizes a DC-DC voltage converter with a control module to discharge energy into the stator winding of the electric traction machine, controlling the discharging process through self-discharging cycles of filtering capacitors, thereby reducing the need for additional dedicated components and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple electromechanical switches and dissipative elements are used for discharging residual energy, then the discharging function is achieved, but the device complexity and bulk increase
Solution Approach 1:
The patent merges the discharging function with the existing DC-DC voltage converter by utilizing its filtering inductor and capacitors. The control module repurposes these existing components to perform both voltage conversion and residual energy discharging, eliminating the need for separate electromechanical switches and dissipative elements.
Solution Approach 2:
The DC-DC voltage converter is designed to perform multiple functions: voltage conversion during normal operation and residual energy discharging during shutdown. The filtering inductor and capacitors serve dual purposes, acting as energy storage elements during operation and as the discharging circuit during shutdown, reducing overall system complexity.
2Ease of operation
If multiple electromechanical resistors and relays are used for discharging, then load impedance control is achieved, but the bulk of the system increases
Solution Approach 1:
The load impedance control function is merged into the DC-DC voltage converter's control module. The existing filtering inductor and capacitors provide the necessary impedance characteristics, and the control module adjusts their effective impedance through electronic control, eliminating the need for multiple physical resistors and relays.
Solution Approach 2:
The patent replaces the mechanical electromechanical system (switches, relays, and physical resistors) with an electronic control system. The control module electronically adjusts the effective impedance by controlling the switching of power electronic devices within the DC-DC converter, achieving impedance control without mechanical moving parts and reducing bulk.
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 allows for efficient and reliable discharge of residual hydrogen fuel cell energy with fewer components, reducing bulk and potential failure points, while ensuring safe and controlled energy dissipation, thus extending the life of the fuel cell system.
Implementation Method 1
discharging the energy of the electrical circuit into the stator winding of the electric traction machine by controlling the DC-DC voltage converter
Implementation Method 2
a DC-DC voltage converter itself comprising a filtering inductor traversed by a current of the filtering inductor
Implementation Method 3
propelled by electricity resulting from an electrochemical reaction between hydrogen, which is stored in a tank, for example, and the oxygen contained in the air
Data Source
AI summary
A method discharges the electrical circuit of a vehicle including at least one traction electric machine and equipped with an electrical supply network including a high-voltage battery and a hydrogen-fuel-cell stack that is associated with a voltage converter, with a high-voltage consumption network including the machine associated with an inverter and appended pieces of equipment, and with a drive module. The discharging method includes the following successive steps: stopping the vehicle, electrically disconnecting the battery from the network, interrupting the supply of hydrogen to the stack, and discharging energy from the electrical circuit into the stator winding of the machine by driving the voltage converter via the drive module.