Power Semiconductor Cooling Using Two-Liquid Forced Convection
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Solution Overview
Problem
Existing cooling devices face a trade-off between simplification and high cooling efficiency, with natural convection lacking efficiency and forced convection requiring additional devices like pumps.
Innovation Solution
A cooling device design that stores insulating oil and a refrigerant liquid with different specific gravities in a mixed state, allowing for forced convection of the insulating oil without additional devices by utilizing the specific gravity difference to stir and cool the oil effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If natural convection is used to cool the insulating oil, then the device structure is simplified, but the cooling efficiency is reduced
Solution Approach 1:
The refrigerant liquid automatically performs forced convection of the insulating oil through its own vaporization and condensation cycles, eliminating the need for external pumps or fans. The system serves itself by using the refrigerant's phase change to drive the cooling process, achieving both structural simplification and high cooling efficiency
Solution Approach 2:
The refrigerant liquid undergoes phase transitions between liquid and vapor states to generate convection currents in the insulating oil. During vaporization, the refrigerant expands and rises, stirring the oil; during condensation, it contracts and sinks, creating continuous forced convection cycles that enhance cooling efficiency without additional mechanical devices
2Productivity
If forced convection is used to cool the insulating oil, then the cooling efficiency is improved, but the device complexity increases due to additional pumps
Solution Approach 1:
The patent replaces mechanical convection devices (pumps, fans) with a thermal-driven fluid system. The refrigerant liquid uses its phase change properties to create natural forced convection currents in the insulating oil, substituting mechanical energy input with thermal energy input to achieve the same cooling effect with simpler equipment
Solution Approach 2:
The refrigerant liquid acts as an intermediary substance that transfers thermal energy from the insulating oil to the cooling system. By introducing this intermediate medium with specific gravity greater than the insulating oil, the system achieves efficient heat transfer and forced convection without requiring direct mechanical intervention
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
Achieves both simplification of the cooling device structure and enhanced cooling efficiency by leveraging the specific gravity difference to facilitate forced convection of the insulating oil, reducing the need for additional convection devices and optimizing heat management.
Implementation Method 1
by performing vaporization heat cooling with the refrigerant liquid
Implementation Method 2
the insulating oil and the refrigerant liquid stored in the tank in the mixed state are present at different positions in a height direction due to a difference in specific gravity
Implementation Method 3
the insulating oil above the vaporized refrigerant liquid can be stirred. Accordingly, the insulating oil having received heat can be forced convection
Data Source
AI summary
A cooling device cools a power semiconductor device. The cooling device includes a tank that accommodates a power semiconductor device, insulating oil, and a refrigerant liquid having a boiling point temperature lower than a boiling point temperature of the insulating oil and a specific gravity larger than a specific gravity of the insulating oil. The insulating oil and the refrigerant liquid are stored in the tank in a mixed state to cool the power semiconductor device.