Inverter-Integrated Motor Layout for Current Sensor Cooling
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Solution Overview
Problem
Existing inverter integrated motors lack an effective cooling mechanism for current sensors, leading to sensing errors and poor reliability, especially when downsizing the device increases heat generation density.
Innovation Solution
The inverter integrated motor incorporates a power module with a flow path forming body that allows a refrigerant to flow through and cool the power module and current sensor, which is positioned between the flow path forming body and the stator's coil end, ensuring at least part of the current sensor is housed in the motor housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inverter integrated motor is downsized to reduce vehicle interior space and increase cruising distance, then the device size is reduced, but heat generation density increases and cooling of inverter components becomes difficult
Solution Approach 1:
The patent merges the motor and inverter into a single integrated unit, combining their housing structures. The inverter is disposed within the motor housing, creating a compact integrated assembly that reduces overall device size while enabling shared cooling resources between the motor and inverter components
Solution Approach 2:
The patent introduces a heat exchanger as an intermediary component that facilitates heat transfer from the inverter components to the cooling medium. The heat exchanger is positioned to receive heat from the power module and current sensor, transferring thermal energy to the cooling medium that circulates through the integrated housing, thereby enabling effective cooling in the downsized configuration
2Volume of moving object
If the current sensor is housed in the motor housing to achieve downsizing, then the overall device size is reduced, but the current sensor experiences poor cooling and sensing errors occur
Solution Approach 1:
The heat exchanger acts as a thermal intermediary that directly contacts the current sensor and power module, extracting heat from these components and transferring it to the circulating cooling medium. This intermediary heat transfer mechanism ensures the current sensor maintains reliable operating temperature despite being housed within the compact motor housing
Solution Approach 2:
The patent employs a hydraulic cooling system where a cooling medium (liquid coolant) circulates through channels in the heat exchanger and housing. This fluid-based thermal management system efficiently removes heat from the current sensor and power module, maintaining their reliability in the integrated downsized configuration
3Manufacturing precision
If the inverter is disposed with less unevenness relative to the downsized motor, then mounting precision is improved, but the device height reduction becomes problematic
Solution Approach 1:
The patent repositions the inverter from a side-by-side or top-mounted arrangement to a configuration where the power module faces the rotation shaft through the stator and rotor. This spatial reorganization in the radial dimension allows compact integration without compromising mounting precision, enabling the inverter to be disposed at an optimized position that balances manufacturing precision with height reduction
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 performance of the current sensor, reduces the overall size of the inverter integrated motor, and improves its reliability by maintaining the current sensor's temperature below a predetermined heat-resistant threshold.
Implementation Method 1
a flow path forming body configured to cause a refrigerant to flow through the power module and cover the power module
Implementation Method 2
the current sensor is disposed between the flow path forming body and a coil end of the stator... at least a part of the current sensor is housed in the motor housing
Data Source
AI summary
An object of the present invention is to provide an inverter integrated motor that achieves both improvement in cooling performance of a current sensor and downsizing of an entire device. An inverter integrated motor includes: a power module that converts a direct current into an alternating current; a flow path forming body that is formed so as to flow and cover a refrigerant in the power module; an inverter that installs the power module and the flow path forming body inside; a current sensor that detects the alternating current; and a motor that houses a stator and a rotor, wherein the power module is disposed at a position facing a rotation shaft of the motor via the stator and the rotor, and the current sensor 13 is disposed between the flow path forming body and a coil end of the stator when viewed from a direction perpendicular to the rotation shaft, and at least a part of the current sensor is housed in a motor housing.