Leakage Resistance Detection Device Using Variable Limit Threshold
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing leakage resistance detection methods for on-board high voltage devices in vehicles face challenges such as inaccurate determination due to high-frequency pulse signals, transient delays, and erroneous measurements caused by abrupt changes in leakage resistance, leading to delayed detection of ground abnormalities.
Innovation Solution
A leakage resistance detection device with a variable limit setting capability, using a coupling capacitor and a repetitive signal output circuit to measure the transition time of the monitoring voltage, allowing for immediate detection of ground abnormalities without waiting for the completion of a half cycle of the charge/discharge pulse, and performing measurements after the monitoring voltage returns to a stable range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high-frequency pulse signal is used for leakage resistance detection, then the detection speed is improved, but measurement accuracy deteriorates due to transient delays and abrupt changes in leakage resistance
Solution Approach 1:
The patent applies preliminary action by measuring the leakage resistance at a predetermined timing (1.5th cycle) before the transient effects of high-frequency pulse signals fully manifest. This timing selection prevents measurement during periods when abrupt changes in leakage resistance occur, thereby maintaining measurement accuracy while still utilizing high-frequency pulse signals for fast detection.
2Loss of time
If the detection is performed immediately without waiting for half cycle completion, then the response time is improved, but measurement reliability deteriorates due to transient delays
Solution Approach 1:
The patent applies parameter changes by optimizing the measurement timing parameter to occur at the 1.5th cycle of the pulse signal. This specific timing parameter selection allows the system to achieve fast response while avoiding transient delay effects that would compromise measurement reliability, thus resolving the contradiction between speed and reliability.
3Device complexity
If a fixed limit threshold is used for leakage resistance determination, then the detection process is simplified, but adaptability deteriorates when leakage resistance characteristics change
Solution Approach 1:
The patent applies dynamics by implementing a variable limit threshold that can be adjusted based on the measured leakage resistance characteristics. Instead of using a fixed threshold, the system dynamically adapts the limit threshold to match changing leakage resistance conditions, thereby maintaining detection simplicity while improving adaptability to various operational states.
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
Enables quick and accurate measurement of leakage resistance, improving the detection of ground abnormalities and reducing false alarms by setting a variable limit threshold and measuring during the 1.5th cycle of the repetitive command signal, thus enhancing the response to transient changes.
Implementation Method 1
a measurement of a leakage resistance Rx is performed via a coupling capacitor 51
Data Source
AI summary
The leakage resistance detection device includes a coupling capacitor having one terminal connected to an on-board high voltage device and another terminal connected to a repetitive signal output circuit, and measures a leakage resistance as a function of a transition time during which a monitoring voltage, which is a potential at the another terminal of the coupling capacitor to be charged/discharged in response to an operation of a charge/discharge switching element that operates in response to a repetitive pulse signal, changes from one predetermined voltage to reach another predetermined voltage. When the measured leakage resistance has become equal to or smaller than a predetermined limit leakage resistance, the leakage resistance detection device generates a resistance abnormality determination output.