Power electronics system, electrical system, and propulsion system for a vehicle such as an aircraft
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Solution Overview
Problem
Current power electronics systems in vehicles, particularly aircraft, face challenges in efficiently integrating and cooling electrical systems using cryogenic liquid hydrogen, which limits their performance and efficiency.
Innovation Solution
A power electronics system with a cryogenic cooling loop and controller that adjusts coolant flow based on electrical properties and connections of power switching elements to minimize drain-source resistance and optimize junction temperature, allowing for improved cooling and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power electronics systems are cooled using conventional cooling methods, then the systems can operate, but the efficiency and performance are limited due to insufficient cooling capabilities
Solution Approach 1:
The patent combines the cooling system with the power electronics system into an integrated unit. The heat exchanger is directly coupled with the power electronics circuit, allowing thermal management to be merged with the electrical system rather than being a separate auxiliary system. This integration improves cooling efficiency while managing system complexity through unified design.
Solution Approach 2:
The cryogenic cooling system serves multiple functions: it cools the power electronics circuit, provides thermal management for high-power operations, and enables the system to operate at optimized temperatures for improved efficiency. The single cryogenic loop structure provides universal thermal management across different operational modes and power levels.
2Temperature
If cryogenic cooling is applied to power electronics, then cooling efficiency improves, but system complexity increases due to specialized components
Solution Approach 1:
The patent changes the temperature parameter of the cooling system to cryogenic levels (below 100K, preferably below 20K). This parameter change enables significantly improved cooling efficiency and thermal management. The control system adjusts coolant flow rates and heat exchanger operations to maintain optimal cryogenic temperatures, transforming the thermal characteristics of the entire power electronics system.
Solution Approach 2:
The system incorporates a controller that monitors thermal conditions and adjusts the coolant flow through the heat exchanger accordingly. This feedback mechanism maintains optimal junction temperatures of the power switching elements by dynamically regulating the cryogenic cooling based on actual thermal states, preventing both overheating and excessive cooling.
3Power
If multiple power switching elements are connected in parallel to increase power capacity, then power output increases, but drain-source resistance increases reducing efficiency
Solution Approach 1:
The patent changes the temperature parameter of the power switching elements to cryogenic levels, which fundamentally alters the electrical characteristics. At these low temperatures, the drain-source resistance of parallel-connected switching elements is significantly reduced, allowing high power capacity to be achieved without the usual penalty of increased resistance and energy loss.
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 enhances the efficiency and reliability of power electronics systems by actively controlling junction temperature, reducing weight and volume, and enabling the use of various semiconductor technologies, thereby improving power density and reducing thermal cycling.
Implementation Method 1
a cryogenic cooling loop configured for cooling the power electronics circuit
Implementation Method 2
a heat exchanging means that is in thermal contact with the power electronics circuit
Implementation Method 3
the control valve is arranged to control the coolant flow to the heat exchanging means
Implementation Method 4
the controller is configured to control the control valve based on the electrical property of drain-source resistance of each power switching element such that the drain-source resistance is reduced or minimized
Implementation Method 5
a fuel tank configured for storing liquefied fuel at cryogenic temperatures below 100 K
Implementation Method 6
the fuel tank is arranged in thermal contact with the cryogenic cooling loop
Data Source
Figure 1
Figure 2
AI summary
In order to improve cooling capabilities for power electronics in vehicles, preferably in aircraft, the invention proposes to use the cryogenic fuel tanks (16) for the cooling of power electronics circuits (26). The power electronics circuit (26) may be cooled via a cryogenic cooling loop (30) by the fuel directly, or the fuel is used to cool a separated coolant tank (32). A control valve (38) controls the coolant flow within the cryogenic cooling loop (30) based on an electrical property of the power switching element of the power electronics circuit (26) and/or based on the way the power switching elements are electrically connected together. For example, the control valve (38) controls the coolant flow such that a junction temperature is achieved which minimizes the drain-source resistance (RDS,on).