Axial Cooling Tower for Electric Machine Electronics
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Solution Overview
Problem
Conventional electric machines, such as vehicle alternators, face challenges in efficiently dissipating heat generated by their electrical circuitry due to increased demands, leading to elevated component temperatures and reduced performance.
Innovation Solution
An electronic package with a cooling tower structure is designed for electric machines, featuring a metallic wall with axially extending air passages and conductive ribs, along with power electronics devices mounted on a radially outer surface, facilitating both air and liquid cooling through primary and secondary cooling paths, and strategically locating control electronics to minimize thermal interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling methods are used for electric machine electronics, then the structure is simple, but heat dissipation efficiency is insufficient leading to elevated component temperatures
Solution Approach 1:
The cooling tower extends axially along the rotation axis of the electric machine, utilizing the axial dimension for heat dissipation. Multiple air passages are arranged axially to maximize cooling surface area without increasing radial footprint, effectively removing heat from power electronics devices through extended cooling paths in the axial direction
Solution Approach 2:
The cooling tower is divided into multiple segments with separate air passages for different cooling zones. First air passages cool power electronics devices mounted on the cooling tower, while second air passages cool other components of the electric machine. This segmentation allows independent optimization of cooling for different thermal loads
2Loss of energy
If increased cooling capacity is provided to handle higher thermal loads, then heat dissipation improves, but the device complexity and space requirements increase
Solution Approach 1:
The cooling tower serves multiple functions: it acts as a heat sink for power electronics devices, provides structural support for mounting electronics, and guides cooling airflow through the electric machine. The same axial space houses both the cooling tower and enables cooling of multiple components, achieving multi-functionality without proportional volume increase
Solution Approach 2:
The air passages are nested within the cooling tower structure, with the cooling tower itself nested within the electric machine housing. This nested arrangement maximizes the use of available space by placing cooling channels inside the structural components rather than adding separate external cooling systems
3Reliability
If power electronics devices are mounted on the cooling tower, then heat transfer efficiency improves, but the manufacturing precision requirements increase
Solution Approach 1:
The cooling tower features localized mounting surfaces with enhanced thermal conductivity and precision finishing at specific radial positions where power electronics devices are mounted. The majority of the cooling tower structure maintains standard manufacturing tolerances, while only the critical mounting zones require high precision to ensure optimal thermal contact
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 effectively reduces heat loss and component temperatures by maximizing cooling airflow and convective heat transfer, enhancing the performance and reliability of electric machines while accommodating various cooling methods and machine topologies.
Implementation Method 1
The cooling tower provides a heat sink for heat loss from the power electronics devices with a primary cooling path for each of the power electronics device extending radially inwardly to the cooling tower
Implementation Method 2
maximizing cooling airflow and convective heat transfer
Implementation Method 3
A plurality of spaced metallic ribs in conductive thermal communication with the radially inner wall surface wherein the ribs traverse the air passage
Data Source
AI summary
An electronic package adapted for connection to a rear frame member of an electric machine. The electronic package includes a cooling tower having first and second axial ends. The cooling tower includes a metallic wall defining radially inner and outer wall surfaces and extending about the package central axis. The radially inner wall surface defines an axially extending air passage through the cooling tower with an inlet proximate the first axial end. Spaced metallic ribs are in conductive thermal communication with the radially inner wall surface traverse and the air passage. Power electronics devices are attached in conductive thermal communication to the radially outer wall surface. The cooling tower provides a heat sink for the power electronics devices with a primary cooling path for each of the power electronics device extending radially inwardly to the cooling tower. An electric machine including such an electronic package is also disclosed.