HV Wiring Y-Capacitance Calibration via Dual Insulation Monitors
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Solution Overview
Problem
Existing methods for determining the Y capacitance in high-voltage wiring systems of electrically operated vehicles are imprecise, posing a risk of electric shock and failing to meet approval standards due to unknown or varying capacitance values.
Innovation Solution
A method using a first insulation monitor within the high-voltage energy store and a second central insulation monitor to compare insulation resistances, adjusting the capacitance value until they match, allowing precise determination of the Y capacitance without prior knowledge of the total capacitance, and enabling the first monitor to function as a backup in case of the second's failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a first insulation monitor is used within the high-voltage energy store to determine insulation resistance, then the system can operate with reduced dependency on the central monitor, but the measurement precision is insufficient without accurate capacitance values
Solution Approach 1:
The system uses feedback by comparing the first insulation resistance value from the energy store monitor with the second insulation resistance value from the central monitor. This comparison enables iterative adjustment of the capacitance value until both measurements converge, thereby improving measurement precision while maintaining system reliability through redundant monitoring.
Solution Approach 2:
The patent replaces the need for precise prior knowledge of total capacitance (a fixed parameter) with a dynamic adjustment mechanism. The capacitance value is iteratively modified based on measurement discrepancies, substituting a static assumption with an adaptive computational approach that resolves the precision-reliability contradiction.
2Ease of manufacture
If the total capacitance value is unknown or varying, then the system must assume a capacitance value which reduces measurement accuracy, but knowing the exact capacitance value requires complex prior measurement procedures
Solution Approach 1:
The system performs preliminary action by assuming an initial capacitance value to enable immediate operation. This preliminary assumption allows the system to start measuring insulation resistance without complex prior calibration, while the iterative adjustment process subsequently refines the precision to compensate for the initial approximation.
Solution Approach 2:
The patent applies dynamics by transforming the capacitance value from a static, pre-determined parameter into a dynamic, adjustable variable. The capacitance value is continuously refined through iterative adjustment based on measurement feedback, enabling the system to adapt to varying conditions and achieve high precision without complex manufacturing procedures.
3Productivity
If the central insulation monitor fails, then the vehicle must be grounded which reduces productivity, but continuing operation without the central monitor compromises safety
Solution Approach 1:
The system implements beforehand cushioning by establishing a backup monitoring capability within the high-voltage energy store. This redundant first insulation monitor is prepared in advance to take over if the central monitor fails, cushioning against the need to ground the vehicle and maintaining both safety and productivity during central monitor failures.
Solution Approach 2:
The first insulation monitor within the energy store performs self-service by independently determining insulation resistance using its own measurement circuitry. This self-contained monitoring capability allows the system to continue operating safely without external assistance from the central monitor, resolving the contradiction between operational continuity and safety assurance.
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 precise determination of Y capacitance values, ensuring compliance with safety standards, reducing false warnings, and allowing continued vehicle operation even with a failed central monitor, thus enhancing safety and reliability.
Implementation Method 1
a first insulation resistance is determined on the basis of a capacitance value of the electrical wiring system by means of a first insulation monitor
Data Source
AI summary
A method for determining a current capacitance value of a Y capacitance of an electrical wiring system for an electrically operated motor vehicle by an electronic computing device where a high-voltage energy store of the electrical wiring system is electrically coupled with an energy store-external part by a switching device. In an energy store-internal part of the electrical wiring system, determining a first insulation resistance on a basis of a capacitance value of the electrical wiring system by a first insulation monitor. Determining a second insulation resistance of the electrical wiring system by a second insulation monitor of the energy store-external part. Comparing the first insulation resistance with the second insulation resistance by the electronic computing device. On a basis of the comparing, adjusting the capacitance value for determining the first insulation resistance by the first insulation monitor such that the first insulation resistance matches the second insulation resistance.