Insulating State Detection Unit with Variable Threshold for Switch Failure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional insulating state detection units for ungrounded power supplies face challenges in accurately detecting switch failures due to noise components in measurement values, leading to erroneous failure detection, especially when trying to detect local short circuit states.
Innovation Solution
An insulating state detection unit that adjusts the failure determination threshold value based on the voltage value measured immediately before failure detection, allowing for accurate detection of switch failures including local short circuit states by ensuring a larger margin for noise components, and includes a voltmeter with a capacitor and switches to measure and compare voltage values effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high threshold value is used for failure detection to avoid erroneous determination from noise components, then the reliability of failure detection is improved, but the ability to detect local short circuit states deteriorates
Solution Approach 1:
The patent applies dynamics by making the threshold value variable rather than fixed. The threshold is dynamically adjusted based on the measured charge voltage of the flying capacitor, which changes according to the operating state. This allows the threshold to adapt between high values (when charge voltage is high) to avoid noise-induced false positives, and low values (when charge voltage is low) to detect local short circuit states, thereby resolving the contradiction between reliability and detection sensitivity.
Solution Approach 2:
The patent changes the parameter of the threshold value based on the charge voltage measurement. By establishing a correspondence relationship between charge voltage and threshold value, the system adjusts the threshold parameter dynamically. When charge voltage is high, a high threshold is used to avoid false positives from noise; when charge voltage is low, a low threshold is used to capture local short circuit conditions, thus resolving the contradiction between avoiding erroneous detection and maintaining detection sensitivity.
2Measurement precision
If a low threshold value is used for failure detection to include local short circuit states in detection range, then the measurement precision for detecting all failure types is improved, but the reliability deteriorates due to increased erroneous detection from noise components
Solution Approach 1:
The patent uses dynamics by transitioning from a static low threshold to a dynamic threshold that adjusts based on charge voltage conditions. This allows the system to maintain low threshold sensitivity when needed for detecting local short circuits, while automatically raising the threshold when charge voltage indicates noisy conditions, thereby preventing erroneous detections while preserving detection precision for actual failures.
Solution Approach 2:
The patent applies parameter changes by making the threshold value a variable that depends on the measured charge voltage. This dynamic parameter adjustment enables the system to optimize detection sensitivity for local short circuit states when charge voltage is low, while simultaneously preventing noise-induced false positives when charge voltage is high, thus resolving the contradiction between measurement precision and reliability.
3Reliability
If the threshold value is set high to avoid noise-induced false positives, then the reliability of detection is improved, but the detection range for switch failures deteriorates
Solution Approach 1:
The patent applies dynamics by making the threshold adaptive rather than fixed. The threshold dynamically follows the charge voltage level, allowing it to be high when charge voltage is high (reducing false positives) and low when charge voltage is low (expanding detection range for various failure modes including local short circuits and dead short circuits, thus resolving the contradiction between reliability and detection versatility.
Solution Approach 2:
The patent changes the threshold parameter based on charge voltage measurements. This dynamic parameter adjustment enables the system to maintain high threshold values to avoid false positives when operating conditions are stable, while automatically lowering the threshold to expand detection range when conditions suggest potential failures, thereby achieving both high reliability and broad detection capability.
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
The solution effectively suppresses erroneous failure detection caused by noise components, ensuring accurate detection of switch failures and local short circuit states within the detection range.
Implementation Method 1
a flying capacitor (C1) that is chargeable with an electric charge amount corresponding to a power supply voltage of a DC power supply (B) insulated from a ground potential
Implementation Method 2
a voltmeter (17) that measures a charge voltage (Va) of the flying capacitor (C1)
Data Source
AI summary
An insulating state detection unit is configured to perform failure detection for switches, which connect a flying capacitor to a sample hold circuit for acquiring a charge voltage and a ground potential, by using a failure determination threshold value according to a variable value. That is to say, the insulating state detection unit is configured to decide the failure determination threshold value by taking, as a reference, a charge voltage of a capacitor of the sample hold circuit charged with electric charge amount corresponding to a charge voltage of the flying capacitor when the flying capacitor is charged with electric charge amount corresponding to an output voltage of a DC power supply.