Insulation Resistance Detection Voltage Stability Switch
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Solution Overview
Problem
Conventional insulation resistance determination apparatuses require a longer time to reach a steady-state value, leading to delays in detecting leakage currents between electrical systems and vehicle bodies due to the use of moving averages for resistance calculation.
Innovation Solution
An insulation resistance detection apparatus that determines insulation resistance based on a currently sampled value of detection voltage instead of a moving average when the voltage becomes stable after a preset change, allowing for earlier convergence to a steady state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If moving average is used for insulation resistance calculation, then measurement precision is improved, but time to reach steady state increases
Solution Approach 1:
The patent dynamically switches between two calculation methods based on system state: during transient states (startup, voltage changes), it uses current sampled values for fast response; during stable states, it uses moving averages for high precision. This dynamic adaptation resolves the contradiction by selecting the appropriate method for each operational phase.
Solution Approach 2:
The patent changes the calculation parameter based on voltage stability detection. When voltage change rate falls below a threshold (indicating stability), the system switches from using current sampled values to moving averages. This parameter change allows the system to achieve both fast response during transients and high precision during steady states.
2Measurement precision
If moving average is used for resistance calculation, then measurement precision is improved, but detection speed for leakage current decreases
Solution Approach 1:
The system dynamically adapts the calculation method based on operational context. During transient phases (startup, voltage transitions), it employs current sampled values enabling fast leakage detection. During stable phases, it switches to moving averages for precise measurement. This dynamic strategy ensures both fast detection and high precision without compromise.
Solution Approach 2:
The patent performs preliminary detection of voltage stability to determine when to switch calculation methods. By detecting when voltage changes become negligible (stability threshold), the system prepares to switch from fast-response mode to high-precision mode, optimizing both detection speed and measurement accuracy at different operational stages.
3Loss of time
If current sampled value is used instead of moving average, then time to reach steady state is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent employs dynamic selection of calculation methods based on voltage stability. During transient states (startup, voltage changes), it uses current sampled values achieving fast convergence. During stable states, it switches to moving averages providing high precision. This dynamic adaptation resolves the contradiction by context-aware method selection.
Solution Approach 2:
The system continuously monitors voltage change rates and uses this feedback to determine when to switch between calculation methods. When voltage stability threshold is reached, the feedback mechanism triggers a switch from fast-response sampled values to high-precision moving averages, ensuring both rapid convergence and accurate measurement.
Data Source
AI summary
In an insulation resistance detection apparatus, a voltage determiner determines whether a detection voltage, which has changed by at least a preset value, becomes stable at around a changed voltage value. A resistance determiner determines a value of an insulation resistance between a ground portion and a power-supply path based on a currently sampled value of the detection voltage instead of a moving average in response to determination that the detection voltage, which has changed by at least the preset value, becomes stable at around the changed voltage value.