Inductor Cooling via Bobbin Nozzle Spray
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Solution Overview
Problem
The inductor assembly in vehicle power converters experiences limited cooling, especially when the vehicle is stationary or at varying angles, due to indirect or splash-based cooling methods which can be inefficient and dependent on fluid circulation and gravitational forces.
Innovation Solution
A bobbin with an internal fluid passage and nozzles is used to direct pressurized fluid directly onto the inductor assembly, providing enhanced convective and conductive heat transfer through a controlled spray pattern, ensuring effective cooling regardless of vehicle position or motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If indirect liquid cooling is used by placing the inductor assembly in a housing surrounded by potting material and thermally connecting to a cooling plate, then the inductor assembly can be cooled via conductive and convective heat loss, but the cooling efficiency is limited and the device complexity increases
Solution Approach 1:
The patent removes the potting material and housing enclosure that characterized indirect cooling systems, exposing the inductor assembly directly to the cooling fluid. This extraction of intermediary materials simplifies the cooling system structure while enabling direct thermal contact between the fluid and inductor surfaces, thereby improving cooling efficiency without requiring complex thermal pathways through multiple materials.
Solution Approach 2:
The patent eliminates the cooling plate as an intermediary thermal transfer component by implementing direct immersion cooling. The cooling fluid directly contacts the inductor assembly, removing the need for thermal conduction through a separate cooling plate structure. This eliminates the intermediary thermal resistance and simplifies the overall cooling system architecture.
2Device complexity
If direct liquid cooling is used by positioning an uncovered inductor assembly within a transmission case where transmission fluid can splash onto the inductor assembly, then the cooling structure is simplified, but the cooling effectiveness is reduced when the vehicle is stationary or at varying angles due to gravitational forces
Solution Approach 1:
The patent incorporates a pump-driven circulation system that dynamically adapts to various vehicle operating conditions. The pump actively circulates the cooling fluid through the transmission case, ensuring consistent cooling effectiveness whether the vehicle is stationary, moving, or at varying angles. This dynamic circulation overcomes the limitations of passive splash cooling that relies on gravitational forces and vehicle motion.
Solution Approach 2:
The patent replaces the gravity-dependent splash cooling mechanism with a pump-driven fluid circulation system. Instead of relying on gravitational forces to move the cooling fluid onto the inductor assembly, an electric pump actively propels the fluid through designated flow paths, ensuring reliable cooling under all vehicle conditions including stationary operation and varying pitch/roll angles.
3Device complexity
If splash cooling is used where transmission fluid splashes onto the inductor assembly, then the cooling system is simpler, but less fluid contacts the inductor assembly when influenced by vehicle pitch and roll angles, reducing cooling efficiency
Solution Approach 1:
The patent replaces the gravity-dependent splash cooling mechanism with a pump-driven fluid circulation system. The pump actively propels the cooling fluid through designated flow paths that ensure consistent fluid contact with the inductor assembly regardless of vehicle orientation. This mechanical substitution eliminates the variability caused by pitch and roll angles, maintaining optimal cooling efficiency under all operating conditions.
Solution Approach 2:
The patent changes the fluid delivery parameters from passive splash based on gravity to active pressurized flow controlled by a pump. The pump system regulates fluid flow rate, pressure, and distribution patterns to ensure adequate cooling coverage. This parameter change from gravity-dependent to pump-controlled delivery maintains consistent cooling efficiency regardless of vehicle pitch and roll angles.
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 solution improves thermal management of the inductor assembly by maintaining effective cooling across various vehicle conditions, increasing current capability and reducing the power rating and cost of the cooling system.
Implementation Method 1
convective heat loss to the circulating fluid
Implementation Method 2
conductive heat loss to the cooling plate
Data Source
AI summary
A vehicle, a vehicle power electronics assembly, and a method of packaging and cooling an inductor assembly are provided. The vehicle has a vehicle electrical system with a variable voltage converter (VVC) and an inductor assembly. The inductor assembly has a core and a winding. A bobbin is connected to and surrounds an outer perimeter of the inductor assembly. The bobbin defines an inlet, an internal fluid passage, and a series of nozzles. The nozzles in the series of nozzles are spaced apart from one another about the bobbin and are positioned to spray fluid directly onto the winding. A fluid system is connected to the inlet to provide pressurized fluid to the inlet.