Two-Phase Refrigerant Circuit for High-Density Electric Motor Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-power electric motors generate excessive heat, requiring advanced thermal management systems that are also compatible with flight conditions, as traditional methods like external fins and liquid cooling are insufficient for high-power density applications.
Innovation Solution
A two-phase refrigerant circuit circulating a dielectric refrigerant through an electric motor and motor drive, with a refrigerant-air heat exchanger that boils the refrigerant to dissipate heat, and a controller regulating the refrigerant flow based on temperature and pressure conditions, while also cooling lubricants in a gearbox.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional thermal management methods (external fins, liquid cooling jackets) are used, then the system structure is simple, but the cooling effectiveness is insufficient for high-power density motors
Solution Approach 1:
The patent employs two-phase refrigerant circulation where the refrigerant undergoes phase transitions (liquid to vapor and back) to absorb and dissipate heat from the motor. The refrigerant is boiled by motor heat and condensed in the heat exchanger, leveraging phase change for high-efficiency thermal management of high-power density motors
Solution Approach 2:
The patent introduces a two-phase refrigerant as an intermediary substance between the motor and the external environment. The refrigerant circulates through the motor and heat exchanger, mediating heat transfer more effectively than direct air cooling or simple liquid cooling jackets
2Power
If high-power density motors are developed, then the power output increases, but the heat generation increases requiring more effective thermal management
Solution Approach 1:
The two-phase refrigerant system leverages phase transitions to handle the increased heat generation from high-power density motors. The refrigerant absorbs latent heat during vaporization and releases it during condensation, providing efficient thermal management for high power applications
Solution Approach 2:
The system changes the thermal management approach by transitioning from single-phase liquid cooling to two-phase refrigerant circulation. This parameter change in the cooling medium's phase state enables more effective heat dissipation for high-power motors
3Productivity
If active control with sensors and valves is implemented, then the thermal management efficiency is optimized, but the system complexity increases
Solution Approach 1:
The patent implements feedback control by using sensors to detect refrigerant flow conditions (temperature, pressure) and using this information to actively control valves that regulate refrigerant flow. This closed-loop feedback optimizes thermal management efficiency by adapting to varying operating conditions
Solution Approach 2:
The system transitions from passive thermal management to active dynamic control. The controller actively adjusts valve positions based on real-time sensor data, making the thermal management system adaptive and responsive to changing motor operating conditions and heat generation rates
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 system effectively manages thermal energy by boiling and subcooling the refrigerant, enhancing cooling efficiency for both the motor and drive, and maintaining compatibility with flight conditions.
Implementation Method 1
the flow of refrigerant is boiled via heat generated by the electric motor
Implementation Method 2
cooling the refrigerant to a subcooled liquid state at the refrigerant-air heat exchanger via thermal energy exchange with a flow of air
Implementation Method 3
The lubricant circuit circulates the flow of lubricant through the refrigerant-air heat exchanger, such that the flow of lubricant is cooled at the refrigerant-air heat exchanger
Data Source
AI summary
An electric motor system includes an electric motor, and a thermal management system. The thermal management system includes a two-phase refrigerant circuit circulating a flow of refrigerant through the electric motor, and a refrigerant-air heat exchanger fluidly connected to the electric motor via the two-phase refrigerant circuit, such that the flow of refrigerant is boiled via heat generated by the electric motor, and returned to a subcooled liquid state to cool the electric motor. A method of dissipating thermal energy from an electric motor includes urging a flow of refrigerant through an electric motor, thereby boiling the flow of refrigerant, directing the flow of refrigerant from the electric motor to a refrigerant-air heat exchanger via a two-phase refrigerant circuit, and cooling the refrigerant to a sub-cooled liquid state at the refrigerant-air heat exchanger via thermal energy exchange with a flow of air through the refrigerant-air heat exchanger.