Electric Compressor Thermal Protection via Localized Housing and Single-Sensor Monitoring
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Solution Overview
Problem
As electric compressors miniaturize, there is a risk of thermal damage to capacitors near switching devices due to heat generated, necessitating a simple hardware configuration and processing method to protect both components effectively.
Innovation Solution
An electric compressor design with a control unit that sets a lower allowable current for a second component with greater cooling capability than a first component, using temperature sensors and calculation units to output alarm signals when predetermined conditions are met, and employing heat conductive members, heat pipes, and Peltier devices to manage thermal resistance and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a capacitor is disposed near a switching device to save space, then miniaturization is achieved, but the capacitor is exposed to thermal damage risk from heat generated by the switching device
Solution Approach 1:
The patent applies local quality by providing different thicknesses of housing (thermal insulation) between components and the refrigerant flow path. Specifically, the housing thickness between the capacitor and refrigerant flow path is greater than between the switching device and refrigerant flow path, creating localized thermal protection where needed while maintaining overall compactness.
Solution Approach 2:
The patent introduces the housing as an intermediary thermal insulation layer between the heat-generating switching device and the temperature-sensitive capacitor. This intermediary structure allows close proximity placement for miniaturization while preventing harmful heat transfer to the capacitor.
2Reliability
If multiple temperature sensors are installed to monitor each component's temperature, then thermal protection accuracy is improved, but hardware complexity increases
Solution Approach 1:
The patent makes the single temperature sensor universal by using it to monitor the temperature of multiple components (switching device and capacitor) through strategic placement. The sensor detects temperature at a location that reflects the thermal state of both components, eliminating the need for separate sensors while maintaining protection accuracy.
Solution Approach 2:
The system uses the thermal coupling between components to its advantage, where the temperature monitoring of one component indirectly provides information about another component's thermal state. The housing's thermal insulation properties create a predictable thermal relationship that allows one sensor to serve multiple monitoring functions.
3Temperature
If the housing thickness between components and refrigerant flow path is increased to improve cooling, then thermal management is improved, but device volume increases
Solution Approach 1:
The patent applies local quality by varying the housing thickness at different locations: greater thickness between the capacitor and refrigerant flow path for thermal protection, and smaller thickness between the switching device and refrigerant flow path for efficient heat dissipation. This localized differentiation achieves both cooling efficiency and component protection without increasing overall device volume.
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 approach allows for the protection of multiple components from thermal damage without the need for multiple temperature sensors, maintaining component safety while reducing system complexity and cost.
Implementation Method 1
A heat conductive member which is able to conduct heat to at least a part of the second component may be provided and the heat conductive member may be in contact with a member having a temperature lower than that of the second component
Implementation Method 2
A heat pipe which is able to exchange heat with the second component may be provided and the heat pipe may be in contact with a member having a temperature lower than that of the second component
Implementation Method 3
A Peltier device which absorbs heat from the second component may be provided
Implementation Method 4
A housing may be provided both between the first component and the refrigerant flow path and between the second component and the refrigerant flow path. A thickness of the housing between the second component and the refrigerant flow path may be smaller than a thickness of the housing between the first component and the refrigerant flow path
Data Source
AI summary
This electric compressor includes a compressor which rotates to compress a fluid, a motor which rotatably drives the compressor, and a control unit which controls current supply to the motor using first and second components. An allowable current for first and second components exposed to the same temperature is set to be smaller in the second component than in the first component. The second component is disposed at a place in which cooling capability is greater than that of the first component so that allowable power of the second component at rated use is greater than allowable power of the first component. This electric compressor includes a temperature sensor which detects the temperature of the first component and a calculation unit which outputs an alarm signal when the detected temperature and a current flowing in the first component satisfy a predetermined condition.