High Voltage Interlock Circuit Constant Current Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High voltage interlock circuits in electric vehicles experience low fault detection accuracy due to variations in contact impedance and external interference, leading to false alarms.
Innovation Solution
A high voltage interlock circuit that injects a constant DC current into high voltage components, using a current generating module, voltage dividing module, and a processing module to determine faults based on collected voltages, reducing external interference and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage type interlock circuit is used, then the circuit structure is simple, but the fault detection accuracy is low due to contact impedance variation and external interference
Solution Approach 1:
The patent replaces the traditional voltage-type detection method with a current-type detection method. By injecting a constant current through the high voltage component and measuring the voltage drop, the system transforms the detection principle from voltage-based to current-based, which is less affected by contact impedance variations and external interference, thereby improving fault detection accuracy
Solution Approach 2:
The patent changes the detection parameter from voltage to current. By using a constant current source to inject current through the high voltage component and measuring the resulting voltage drop across known resistance, the system transforms the measurement parameter, making the detection immune to external voltage interference and contact impedance variations
2Reliability
If a constant DC current is injected into the high voltage component module, then the accuracy of fault determination is improved, but the device complexity increases due to additional modules
Solution Approach 1:
The patent designs the current generating module to serve multiple functions: it provides the constant current for fault detection, and can also simulate normal operating conditions for testing purposes. The same module structure is used whether detecting faults or verifying normal operation, reducing overall system complexity through functional consolidation
Solution Approach 2:
The voltage dividing module automatically adjusts the voltage signal levels without requiring external calibration or adjustment mechanisms. The circuit self-regulates the voltage division ratio based on the injected current, eliminating the need for complex external control systems while maintaining detection accuracy
3Measurement precision
If external interference is reduced, then the detection accuracy is improved, but the circuit requires additional filtering or shielding components
Solution Approach 1:
The patent eliminates the need for complex filtering and shielding by replacing voltage-based detection with current-based detection. Since the constant current injection method is inherently immune to external voltage interference (such as static electricity), additional interference mitigation components become unnecessary
Solution Approach 2:
The patent converts the potential harm of external electrical interference into a benefit by using a detection method that is inherently insensitive to such interference. The constant current injection technique naturally rejects external voltage fluctuations, turning the challenging electrical environment into an advantage where interference becomes irrelevant to detection accuracy
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 proposed solution enhances the accuracy of fault detection in high voltage interlock circuits by mitigating external interference, thereby improving the reliability of fault determination in electric vehicle systems.
Implementation Method 1
the other end of the current generating module is connected to a first terminal of a high voltage component module to inject a constant direct current (DC) current into the high voltage component module
Implementation Method 2
a first voltage dividing module, wherein one end of the first voltage dividing module is connected to a second terminal of the high voltage component module
Data Source
AI summary
The disclosure provides high voltage interlock circuit and detection method. The circuit comprises: a power module, a positive electrode of the power module being connected to one end of a current generating module; the current generating module, the other end of the current generating module being connected to a first terminal of a high voltage component module to inject a constant DC current into the high voltage component module; a first voltage dividing module, one end of the first voltage dividing module being connected to a second terminal of the high voltage component module, and the other end of the first voltage dividing module being connected to a negative electrode of the power module and a power ground; and a processing module to determine a fault of the high voltage component module based on a first voltage collected from the second terminal of the high voltage component module.