Device Protection Apparatus Using Refrigerant-Device Temperature Difference

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Solution Overview

Problem

The existing methods for torque limitation in motors fail to effectively suppress temperature rises at heat-generation parts, especially when the surrounding temperature is high, leading to potential overheating issues.

Innovation Solution

A device protection apparatus and method that detect temperature differences between a refrigerant and a device, applying drive limitations when these differences exceed predetermined thresholds, and further limiting the device's operation when its temperature exceeds specific thresholds to prevent overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If torque limitation is applied based on inverter temperature detection and smoothing processing, then the control system can manage thermal conditions, but temperature of heat-generation parts becomes too high when surrounding temperature is very high because torque limitation is not applied at appropriate timing

Engineering Contradiction:
Improveinverter temperatureVSAvoidheat-generation part temperature control
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The system calculates temperature difference between the heat-generation part and refrigerant in advance, and applies torque limitation when this difference exceeds a threshold, before the heat-generation part temperature becomes critically high. This preliminary detection and action prevents excessive temperature rise by intervening early in the thermal escalation process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors both the heat-generation part temperature and refrigerant temperature, calculates their difference in real-time, and uses this feedback to dynamically adjust torque limitation. This closed-loop feedback mechanism ensures torque limitation is applied at the appropriate timing based on actual thermal conditions, resolving the issue of delayed response in high ambient temperature scenarios.

Inventive Principle:
Principle #23Feedback

2Temperature

If drive limitation is applied when temperature difference exceeds threshold, then temperature rise at heat-generation part is suppressed, but device operation is restricted

Engineering Contradiction:
Improveheat-generation part temperatureVSAvoiddevice operation capacity
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The system dynamically adjusts drive limitation based on real-time temperature difference measurements. When the temperature difference between heat-generation part and refrigerant is within acceptable thresholds, full device operation is permitted. When the difference exceeds thresholds, torque limitation is applied proportionally. This dynamic adjustment optimizes the balance between temperature control and operational capacity, avoiding unnecessary restrictions when thermal conditions are acceptable.

Inventive Principle:
Principle #15Dynamics

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 effectively suppresses temperature rises at heat-generation parts, extending the operational life of the device by reducing heat loads and preventing overheating, even in high environmental temperatures.

Implementation Method 1

detecting each of a temperature of a refrigerant used for cooling a device (3) and a temperature of the device

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3661049B1Apparatus protection device and apparatus protection method
Publication Date: 2022.01.05 NISSAN MOTOR CO LTD
  • EP3661049B1 patent drawingFigure 1
  • EP3661049B1 patent drawingFigure 2
  • EP3661049B1 patent drawingFigure 3A

AI summary

A device protection apparatus comprising a first sensor for detecting temperature of a refrigerant used for cooling a device including a heat-generation part, a second sensor for detecting temperature of the device, and a controller 10 that applies drive limitation to the device based on a first detected temperature detected by the first sensor and a second detected temperature detected by the second sensor, wherein the controller 10 calculates a temperature difference between the first detected temperature and second detected temperature, applies drive limitation to the device when the temperature difference is higher than a predetermined temperature difference threshold value, and applies drive limitation to the device when the second detected temperature is higher than a predetermined first temperature threshold value.