Vehicle Motor Inverter Cooling Passage Design
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Solution Overview
Problem
Electric vehicle and hybrid vehicle motor power plants face challenges in cooling performance for inverters, which can lead to overheating and component damage due to the inverter's lower allowable temperature than the motor, necessitating enhanced cooling solutions for switching elements and other components.
Innovation Solution
A motor apparatus design with a case having separate inverter spaces for the power converter, capacitor, and control circuit, and a cooling passage with distinct cooling parts for each, where the coolant flow path is optimized to prioritize cooling of the power converter, enhancing the cooling performance by reducing resistance and improving heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the inverter is cooled using a conventional cooling passage design, then the motor and inverter can be cooled, but the cooling performance for the inverter is insufficient leading to overheating and component damage
Solution Approach 1:
The cooling passage is segmented into a first cooling part and a second cooling part, with the first cooling part dedicated to cooling the power converter and the second cooling part dedicated to cooling the capacitor. This segmentation allows optimized cooling for each component based on its specific thermal requirements and position in the cooling medium flow path.
Solution Approach 2:
The cooling passage design provides different cooling characteristics to different locations: the first cooling part is positioned to receive cooling medium with lower temperature and higher flow rate to cool the power converter which generates more heat, while the second cooling part receives cooling medium after it has passed through the first cooling part. This local differentiation of cooling quality addresses the specific thermal needs of each component.
2Temperature
If the cooling passage is designed to prioritize cooling of the power converter, then the cooling performance for the power converter is enhanced, but the cooling passage length increases
Solution Approach 1:
The cooling passage is designed to extend in multiple spatial dimensions rather than a simple linear path. The first cooling part and second cooling part are arranged to utilize three-dimensional space within the housing, allowing the cooling medium to flow through both cooling parts without requiring a significantly increased overall passage length. This dimensional optimization enables prioritized cooling of the power converter while controlling the total passage length.
3Temperature
If the inverter components are accommodated in separate spaces, then the cooling performance is improved, but the device complexity increases
Solution Approach 1:
The first cooling part and second cooling part are merged into a single continuous cooling passage that flows through both components. This merging approach allows the cooling system to treat multiple components separately (improving cooling performance) while using a unified passage structure (reducing complexity compared to entirely separate passages). The cooling medium flows sequentially through both parts in an integrated manner.
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
The design effectively enhances the cooling performance of the inverter unit, preventing overheating and improving the reliability and performance of the motor apparatus by ensuring efficient heat dissipation for critical components.
Implementation Method 1
a cooling passage (70) configured to enable heat transfer from the power converter (31) and the capacitor (32) to the cooling medium
Implementation Method 2
a cooling passage (70) configured to enable heat transfer from the power converter (31) and the capacitor (32) to the cooling medium flowing in the cooling passage (70)
Implementation Method 3
at least one pump (50) configured to forward the cooling medium to the cooling passage (70)
Data Source
Figure 1
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AI summary
A motor apparatus for a vehicle includes a motor unit (20), an inverter unit (30), a case (40), and a pump (50). The case (40) has a motor space (61) accommodating the motor unit (20), two or more inverter spaces (62, 63) each accommodating the inverter unit (30), and a cooling passage (70). The inverter spaces (62, 63) are provided adjacent to the motor space (61) via respective walls (41a, 41b), and each accommodating at least one of the capacitor (32), the power converter (31), and the control circuit (33). The cooling passage (70) includes a first cooling part (71) configured to cool the power converter (31) and a second cooling part (72) configured to cool the capacitor (32). A length (L1) of the cooling passage (70) from a discharging part (51) of the pump (50) to the first cooling part (71) is made shorter than a length (L2) of the cooling passage (70) from the discharging part (51) to the second cooling part (72).