Inclined Power Converter Cooling Passage for Rotary Machine Units
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Solution Overview
Problem
The cooling effect of power converters in rotary electric machine units is reduced due to the accumulation of heat and air bubbles within the cooling device, which affects the efficiency of coolant flow and component cooling.
Innovation Solution
The power converter is positioned outside the rotary electric machine with a device housing inclined relative to the vertical direction, featuring a device cooling passage where the coolant inlet is lower than the outlet, preventing air bubbles from accumulating and enhancing the cooling effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the power converter is provided outside the rotary electric machine, then the cooling effect is improved, but the device complexity increases
Solution Approach 1:
The power converter housing is merged with the cooling device into a single integrated structure. The housing serves dual functions as both the enclosure for the power converter and as the cooling device that directs coolant flow, eliminating the need for separate cooling components and reducing overall device complexity while maintaining effective cooling.
2Reliability
If the coolant inlet is positioned lower than the outlet, then air bubble accumulation is prevented, but the device complexity increases
Solution Approach 1:
The conventional coolant flow direction is inverted by positioning the inlet at the lower portion and the outlet at the upper portion of the cooling device. This inverted arrangement utilizes gravity to prevent air bubble accumulation in the cooling passage, improving cooling reliability without requiring additional complex components.
3Productivity
If the device housing is inclined relative to the vertical direction, then coolant flow is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The device housing is designed with an asymmetric inclined structure rather than a symmetric vertical orientation. This asymmetric design naturally directs coolant flow along the cooling passage to enhance cooling efficiency, while the inclination angle is optimized to balance performance improvement with manufacturability, avoiding excessive precision requirements.
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 enhances the cooling efficiency of the power converter by minimizing the impact of heat accumulation and air bubbles, ensuring effective coolant flow and improved component cooling.
Implementation Method 1
a cooling device configured to cool the power converter and the rotary electric machine with coolant flowing inside the cooling device
Implementation Method 2
the device housing is inclined relative to a vertical direction, such that one end and an other end of the device cooling passage in the circumferential direction are an upper end and a lower end
Data Source
AI summary
In a motor unit, a power converter is provided to an outer circumferential surface of a motor case at a position distant from an outer top portion in a circumferential direction. In a power converter, a power module and a control board are accommodated in an internal space of a device case. A power converter is provided with a device cooler. A device cooler has a device cooling passage extending along a power module. In the device cooling passage, a device inlet, into which coolant flows, and a device outlet, from which coolant flows out, are provided side by side in a circumferential direction. The device inlet is located a position lower than the device outlet in the Y direction.