Leakage Detection Circuit with Continuous Robustness Check
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Solution Overview
Problem
Existing leakage detection circuits in electrified vehicles lack continuous robustness checks, which are crucial for ensuring the functionality and accuracy of leakage current detection, particularly in preventing balanced fault conditions where both positive and negative terminal resistances are too low, leading to undetected leakage currents.
Innovation Solution
A circuit configuration that continuously monitors leakage detection functionality by using ohmic voltage dividers, differential amplifiers, and analog-to-digital converters to detect voltages at various terminals, allowing a processor module to calculate checkproducts and perform continuous robustness checks without expensive switches, thereby detecting balanced fault conditions and initiating fault responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional leakage detection circuits are used without continuous robustness checks, then device complexity is reduced, but reliability deteriorates due to undetected balanced fault conditions
Solution Approach 1:
The patent combines the leakage detection function and robustness check function into a single integrated circuit system. The same voltage dividers, differential amplifiers, and ADCs are used for both detecting leakage currents and verifying circuit functionality, eliminating the need for separate check circuits and reducing overall device complexity while maintaining high reliability
Solution Approach 2:
The patent implements a feedback mechanism where the processor continuously monitors the relationship between voltages V1 and V2 and compares them against expected values derived from V3. When discrepancies indicate potential faults, the system provides feedback by triggering fault responses or alerts, enabling continuous verification of detection circuit functionality without adding significant complexity
2Reliability
If switches are added to enable robustness checks at predetermined times, then reliability improves, but device complexity and cost increase
Solution Approach 1:
The patent performs robustness checks continuously during normal operation rather than at predetermined intervals using switches. The system continuously monitors voltage relationships and performs fault detection in real-time, eliminating the need for switches while maintaining continuous verification capability and improving reliability
Solution Approach 2:
The leakage detection circuit performs its own robustness checks using its existing components (voltage dividers, differential amplifiers, ADCs, and processor). The system uses its own operational data (voltages V1, V2, and V3) to verify its functionality, eliminating the need for external check circuits or switches and reducing device complexity
3Reliability
If balanced fault conditions occur with low resistance at both terminals, then leakage current increases, but detection capability deteriorates without proper robustness checks
Solution Approach 1:
The patent replaces traditional mechanical switch-based check systems with an electronic computational approach. The processor module uses mathematical relationships between voltages V1, V2, and V3 to detect faults, substituting electronic computation for mechanical switching and enabling more sophisticated fault detection capabilities including balanced fault conditions
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 enables continuous and accurate leakage current detection and robustness checks, preventing undetected balanced fault conditions and ensuring reliable leakage detection without the need for expensive switches, thus enhancing the operational efficiency and safety of electrified vehicles.
Implementation Method 1
A first ohmic voltage divider is coupled to the ESD positive terminal and a chassis, and a second ohmic voltage divider is coupled to the ESD negative terminal and the chassis
Implementation Method 2
An example circuit can include a first differential amplifier configured to detect a voltage V1 at the first voltage divider, and a second differential amplifier configured to detect a voltage V2 at the second voltage divider
Implementation Method 3
A first analog-to-digital converter is configured to receive input from both the first and second differential amplifiers and provide digitized V1 and V2 values to a processor module
Implementation Method 4
A leakage detection circuit is typically in the form of either an ohmic circuit, in which a voltage across a detection resistor indicates the presence of leakage current
Data Source
AI summary
A leakage detection circuit with integrated robustness check provides leakage detection and continuous robustness check capability. A circuit can include a first voltage divider coupled to a chassis ground and a positive terminal of a traction energy storage device (ESD). A second voltage divider, connected in series to the first voltage divider, can be coupled to the chassis ground and a negative terminal of the ESD. A third voltage divider can be coupled to both the positive and negative ESD terminals. A checkproduct based on a voltage detected at the third voltage divider can be compared to a sum VS of voltages detected at first and second voltage dividers to check for a circuit fault. Voltages detected at the first and second voltage dividers, and SOC values, can be used to detect leakage faults, including balanced leakage faults, and a fault response can be performed.