Adaptive Threshold for Inverter Temperature Sensor Abnormality Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sensor abnormality determining apparatuses fail to detect abnormalities in temperature sensors for power elements when the deviation between inferred and actual cooling water temperatures is low, due to a constant abnormality determining threshold that is not adaptive to varying electric current conditions.
Innovation Solution
The apparatus sets different determination temperature differences based on whether the temperature detected by the temperature sensor is higher or lower than the water temperature sensor, with a lower threshold when the temperature is lower, allowing for abnormality detection even with small deviations, and withholding determination during high electric current conditions to prevent erroneous results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant abnormality determining threshold is used, then the system avoids erroneous determination during high current operation, but fails to detect abnormalities when temperature deviation is small
Solution Approach 1:
The abnormality determining threshold is changed from a constant value to a dynamic value that varies based on the detected temperature. When the detected temperature is lower than the water temperature, a first (lower) threshold is used; when the detected temperature is higher, a second (higher) threshold is used. This dynamic adaptation allows the system to detect abnormalities accurately across different operating conditions.
Solution Approach 2:
The system changes the parameter of the abnormality determining threshold based on the temperature difference between the detected temperature and water temperature. By adjusting this threshold parameter according to operating conditions, the system achieves both high detection accuracy and adaptability to varying current conditions.
2Reliability
If the abnormality determining threshold is set to a high value, then erroneous determination is prevented during high current operation, but abnormality detection capability is reduced
Solution Approach 1:
Different abnormality determining thresholds are applied to different local conditions (temperature ranges). A lower threshold is used when the detected temperature is below water temperature, and a higher threshold is used when the detected temperature exceeds water temperature. This localized approach optimizes detection sensitivity for each specific operating condition.
Solution Approach 2:
The threshold dynamically adjusts based on the relationship between detected temperature and water temperature, enabling the system to maintain high detection sensitivity without increasing false positive rates during high current operation.
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 enables the detection of temperature sensor abnormalities even with small temperature deviations and prevents erroneous determinations by adapting to varying electric current conditions, improving the accuracy and reliability of sensor monitoring.
Implementation Method 1
a temperature sensor 51 that detects a temperature of the power element 3a
Implementation Method 2
a water temperature sensor 52 that detects a temperature of the cooling water 41
Implementation Method 3
cooling water 41 for cooling the power element 3a
Implementation Method 4
cooling water circulation path 42 having cooling water 41 for cooling the power element 3a circulating therein
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To provide a sensor abnormality determining apparatus that detects an abnormality of a temperature sensor for detecting a power element temperature, even when the difference between the power element temperature and the temperature of the cooling water for cooling the power element is low. This sensor abnormality determining apparatus is applied to an inverter (3) that is provided with: a power element (3a); a cooling water circulation path (42) having cooling water (41) for cooling the power element (3a) circulating therein; a temperature sensor (51) that detects a temperature of the power element (3a); and a water temperature sensor (52) that detects a temperature of the cooling water (41) circulating in the cooling water circulation path (42). The sensor abnormality determining apparatus is configured such that the apparatus is provided with: an abnormality determining section (5a), which determines that the temperature sensor (51) is abnormal when a temperature difference (AT) between the temperature detected by means of the temperature sensor (51) and the water temperature detected by means of the water temperature sensor (52) is larger than a previously set determination temperature difference; and a determination temperature setting section (5b) whereby the determination temperature difference for the time when the temperature detected by means of the temperature sensor (51 ) is lower than the water temperature detected by means of the water temperature sensor (52) is set at a lower value than the determination temperature difference for the time when the temperature detected by means of the temperature sensor (51) is higher than the water temperature detected by means of the water temperature sensor (52).