Electric Motor Cooling Control with Multi-Sensor Temperature Verification
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Solution Overview
Problem
Existing cooling systems for electric vehicles may erroneously recognize refrigerant temperatures, leading to decreased cooling performance and potential overheating of electric components due to noise interference and incorrect abnormality determinations based on temperature differences.
Innovation Solution
A control device that integrates temperature information from multiple sensors, including those for refrigerants, the rotating electrical machine, and outside air, to verify and accurately determine oil temperature values, thereby preventing erroneous recognition and ensuring appropriate cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature difference method is used for abnormality determination, then abnormality detection capability is improved, but false determination increases due to other temperature factors
Solution Approach 1:
The patent segments the temperature verification process into multiple independent comparison operations: comparing oil temperature with water temperature, comparing with motor temperature, comparing with inverter temperature, and comparing with outside air temperature. Each comparison is evaluated separately against its own threshold, allowing the system to identify which specific comparison fails, thereby reducing false determinations while maintaining detection capability.
Solution Approach 2:
The patent extends the verification process from a single temperature difference comparison to a multi-dimensional verification system that considers four different temperature parameters (water temperature, motor temperature, inverter temperature, outside air temperature) with four different threshold values. This multi-dimensional approach allows the system to cross-validate temperature readings from multiple sources, significantly reducing false abnormality determinations.
2Ease of operation
If oil temperature sensor is installed in motor or gear box, then cooling control accuracy is improved, but measurement precision deteriorates due to noise from inverter
Solution Approach 1:
The patent implements a feedback-based verification mechanism where the oil temperature reading is continuously cross-checked against multiple other temperature measurements (water temperature, motor temperature, inverter temperature, outside air temperature) and their respective thresholds. If the oil temperature deviates beyond acceptable thresholds from these reference measurements, the system identifies this as an abnormality and adjusts cooling control accordingly, effectively compensating for noise-induced measurement errors through continuous feedback validation.
3Loss of energy
If cooling performance is reduced due to erroneous temperature recognition, then energy consumption is improved, but component reliability deteriorates due to overheating
Solution Approach 1:
The patent performs preliminary verification of temperature measurements before using them for cooling control decisions. By pre-comparing the oil temperature against multiple reference temperatures and thresholds, the system identifies and corrects erroneous temperature readings before they can trigger inappropriate cooling reduction. This preliminary action prevents false cooling reduction based on noisy temperature measurements, thereby maintaining component reliability while avoiding unnecessary energy consumption.
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 avoids erroneous oil temperature recognition, maintains optimal cooling performance, and prevents overheating of electric components, ensuring reliable vehicle operation by using a majority decision based on multiple temperature parameters and adaptive threshold values.
Implementation Method 1
a first temperature detection unit that detects a temperature of a first refrigerant that exchanges heat with at least the rotating electrical machine
Implementation Method 2
a second temperature detection unit that detects a temperature of a second refrigerant that exchanges heat with at least a winding of the rotating electrical machine and is cooled by the first refrigerant
Data Source
AI summary
A control device that controls cooling of a rotating electrical machine for driving a vehicle includes an arithmetic operation unit that executes predetermined arithmetic operation processing, and a storage unit that is accessible by the arithmetic operation unit. First temperature information from a first temperature detection unit that detects a temperature of a first refrigerant that exchanges heat with at the rotating electrical machine, second temperature information from a second temperature detection unit that detects a temperature of a second refrigerant that exchanges heat with a winding of the rotating electrical machine and is cooled by the first refrigerant, third temperature information from a rotating electrical machine temperature detection unit detects a temperature of the rotating electrical machine, and fourth temperature information from an outside air temperature detection unit are input. The second temperature information is verified by using the first, second, third, and fourth temperature information.