Motor Embedded Power Conversion Circuit Thermal Management
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Solution Overview
Problem
Current motors with built-in power conversion circuits face challenges in size reduction, heat transfer efficiency, mechanical strength of soldered joints, and increased manufacturing costs due to limited heat transfer and high thermal contraction stress, which restricts their operating range and reliability.
Innovation Solution
A motor design featuring a printed-circuit board with a surface-mount main circuit device, a heat spreader bonded to one surface of the device chip, and heat-transferring copper foil connected via through holes, allowing heat transfer to a fluid flowing through a cup, enhancing thermal conductivity and mechanical coupling strength without the need for metal heat-transferring fins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If surface-mount main circuit devices are used to reduce motor size, then device package size is reduced, but heat transfer efficiency deteriorates due to limited space for heat dissipation structures
Solution Approach 1:
The patent merges the heat spreader and cooling plate into a single integrated component that combines heat conduction and fluid cooling functions. This integration allows efficient heat dissipation from surface-mount devices without requiring additional space, resolving the contradiction between miniaturization and heat transfer efficiency
Solution Approach 2:
The patent introduces a cooling fluid as an intermediary medium to transfer heat from the main circuit devices. The fluid circulating through the cooling plate provides an efficient heat transfer pathway that overcomes the limited heat dissipation capability of compact surface-mount packages
2Temperature
If metal heat-transferring fins are added to improve heat transfer, then heat dissipation is enhanced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the heat dissipation function from traditional metal fins and relocates it to a fluid-based cooling system. This eliminates complex fin structures while maintaining effective heat transfer through the cooling plate and circulating fluid
Solution Approach 2:
The patent employs a hydraulic cooling system where fluid circulation through the cooling plate provides heat dissipation. This fluid-based approach replaces solid metal fin structures, reducing mechanical complexity while enhancing heat transfer efficiency
3Volume of moving object
If surface-mount devices are mounted on printed-circuit boards, then size is reduced, but mechanical strength of soldered joints deteriorates due to thermal contraction stress
Solution Approach 1:
The patent introduces a heat spreader as an intermediary component between the surface-mount devices and the printed-circuit board. This heat spreader acts as a thermal buffer that reduces thermal contraction stress transmission to the soldered joints, maintaining mechanical strength while enabling compact surface-mount configuration
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 configuration improves heat transfer efficiency, reduces motor size, widens the operating range, increases mechanical strength, and lowers manufacturing costs by utilizing fluid-based heat transfer and automated production processes.
Implementation Method 1
a heat spreader is bonded to one surface of a device chip included in the package, the one surface facing toward the printed-circuit board... The heat spreader is coupled to the heat-transferring copper foil via a through hole penetrating through the printed-circuit board
Implementation Method 2
heat-transferring copper foil provided over an area of the surface of the printed-circuit board that is the reverse surface of the mounting surface, the area facing a bottom of the cup... heat generated from the main circuit device is transferred to the outside from the metal heat-transferring plate via the lead
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 3A
AI summary
To provide a motor with a built-in power conversion circuit and other apparatuses each of which is small in size with a superior heat-transferring characteristic, includes the power conversion circuit having a wide operating range, has an increased strength at a mechanical coupling between a main circuit device and a printed-circuit board, and reduces manufacturing cost. A motor with a built-in power conversion circuit includes a cup 8 having a cylindrical shape with a closed end and providing a space therein in which a fluid flows, the cup 8 being provided on an inner side of a stator 9b such that the closed end is in contact with or in proximity to a printed-circuit board 1; and heat-transferring copper foil 13 provided over an area of a surface of the printed-circuit board 1 that is a reverse surface of a mounting surface having a main circuit device 2, the area facing the closed end of the cup 8. In the main circuit device 2, a heat spreader 21 is bonded to one of two surfaces of a device chip 20 included in a package, the one of the two surfaces facing toward the printed-circuit board 1 in an orientation for mounting onto the printed-circuit board 1. The heat spreader 21 is thermally and mechanically coupled to the heat-transferring copper foil 13 via a through hole 12 penetrating through the printed-circuit board 1.