In-Wheel Motor Cooling Layout With Parallel Inverter Flow
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Solution Overview
Problem
In-wheel motors in electric vehicles generate significant heat due to electrical resistance, which affects their performance and durability, and existing cooling methods like convection and oil cooling are inefficient or require additional components.
Innovation Solution
A water cooling system with a coolant circulation circuit that connects in-wheel motors and inverters in parallel and series configurations, using water pumps to distribute coolant effectively, and integrates with a radiator and optional heat exchangers to manage heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If convection cooling with external air is used in the motor housing, then the cooling method is simple, but the cooling efficiency is greatly reduced
Solution Approach 1:
The patent applies hydraulic cooling by circulating coolant through channels formed in the stator core and stator yoke. The coolant flow paths are integrated into the motor structure, allowing efficient heat removal from the in-wheel motor components without requiring complex external cooling systems. This resolves the contradiction by providing high cooling efficiency through internal fluid circulation while maintaining relatively simple overall system structure.
2Temperature
If oil cooling method is used to cool the in-wheel motor, then the cooling effectiveness is improved, but a separate oil cooler device is required
Solution Approach 1:
The patent merges the cooling function directly into the motor structure by forming coolant flow paths within the stator core and stator yoke themselves. The stator components serve dual purposes: electromagnetic function and heat dissipation function. This eliminates the need for separate oil coolers or external cooling devices, resolving the contradiction by achieving effective cooling while minimizing additional system complexity.
Solution Approach 2:
The stator core and stator yoke perform multiple functions simultaneously: they provide the electromagnetic structure necessary for motor operation and also serve as heat exchangers through integrated coolant channels. This multi-functionality allows the same components to handle both motor operation and thermal management, eliminating the need for dedicated cooling devices and reducing overall system complexity.
3Weight of moving object
If in-wheel motors are mounted in wheels, then the vehicle weight is reduced by omitting intermediate power transmission devices, but heat management becomes more challenging
Solution Approach 1:
The cooling channels are nested within the stator core and stator yoke structures. The coolant flow paths are formed inside the existing motor components, utilizing the internal space of the stator assembly. This nested arrangement allows heat management to be integrated into the motor structure itself, addressing thermal challenges without adding external cooling components that would increase vehicle weight.
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 system provides efficient heat management for in-wheel motors and inverters, enhancing their performance and durability by effectively dissipating heat through a coordinated coolant circulation and exchange process.
Implementation Method 1
a coolant circulation line configured to cool the in-wheel motor and the inverter
Implementation Method 2
a radiator provided to pass a coolant having cooled the plurality of inverters and the in-wheel motors therethrough so as to dissipate heat from the coolant
Implementation Method 3
water pumps configured to pump the coolant on the coolant circulation line so as to circulate the coolant along the coolant circulation line
Implementation Method 4
The in-wheel motor mounted in the wheel of the vehicle generates Joule heat due to resistance while current flows in a coil of a stator
Data Source
AI summary
An embodiment cooling system for in-wheel motor vehicles includes first coolant flow paths provided in in-wheel motors mounted in wheels of a vehicle, second coolant flow paths provided in inverters configured to drive and control the in-wheel motors, a radiator configured to pass therethrough a coolant having cooled the inverters and the in-wheel motors to dissipate heat from the coolant, a coolant circulation line connecting the first and second coolant flow paths and the radiator, wherein a portion of the coolant circulation line located at upstream sides of the inverters based on a coolant circulation path is branched off into secondary coolant circulation lines respectively connected to the inverters, and water pumps disposed on the coolant circulation line and configured to pump the coolant, wherein the coolant pumped by the water pumps is distributed and passes through the inverters in parallel by way of the secondary coolant circulation lines.