Relay Drive Circuit Fault Detection in Electric Vehicle Control
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Solution Overview
Problem
Current fault diagnosis solutions are inadequate for drive circuits of relays in electric vehicles, particularly due to the mechanical nature of relays which can lead to aging and failure, impacting vehicle safety and reliability.
Innovation Solution
A detection circuit is designed to identify faults in the drive circuit of an electrical control device by monitoring electrical signals and determining the presence of open-circuit or shorted-to-ground faults through a detection power module, switch modules, and a control module, enabling effective fault detection and diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relay is used to control high-voltage loops indirectly, then safety is improved by isolating the control circuit from high voltage, but the mechanical nature of the relay leads to aging and failure over time
Solution Approach 1:
The detection circuit performs preliminary fault detection on the relay drive circuit before the relay actually fails. By continuously monitoring electrical characteristics and comparing them against threshold values, the system can identify degradation trends and potential failures in advance, allowing for preventive maintenance or replacement before the relay completely fails during operation.
Solution Approach 2:
The detection circuit establishes a feedback mechanism that continuously monitors the electrical characteristics of the relay drive circuit and provides real-time status information to the control system. This feedback enables the system to detect abnormalities, judge fault types, and respond appropriately, thereby compensating for the inherent mechanical limitations of the relay through active monitoring and control.
2Device complexity
If no detection circuit is implemented, then device complexity is reduced, but fault diagnosis capability is insufficient
Solution Approach 1:
The detection circuit is designed with modular segmentation, separating the detection function from the main control circuitry. The detection circuit includes distinct modules for acquiring electrical characteristics, judging fault types, and generating detection results, which can be independently implemented and maintained. This segmentation adds fault diagnosis capability while keeping the overall system architecture clear and manageable.
Solution Approach 2:
The detection circuit acts as an intermediary between the relay drive circuit and the control system. Rather than requiring the control system to directly analyze complex electrical signals from the relay, the detection circuit processes these signals, extracts relevant features, and presents simplified fault information to the control system, thereby enabling effective fault diagnosis without significantly complicating the control architecture.
3Measurement precision
If comprehensive fault detection is implemented, then diagnostic accuracy is improved, but detection time and processing complexity increase
Solution Approach 1:
The detection circuit implements partial monitoring by focusing on key electrical characteristics that are most indicative of relay faults, rather than attempting to measure all possible parameters. The judgment module uses predetermined threshold values for critical parameters to quickly determine fault types. This approach achieves sufficient diagnostic accuracy for safety-critical applications while minimizing detection time and processing complexity.
Data Source
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AI summary
Embodiments of this application relate to the technical field of electronics, and disclose an electrical control device detection circuit, a detection method, and an electric vehicle. In some embodiments of this application, the detection circuit includes a drive circuit configured to detect an electrical control device. The drive circuit includes a drive power module, a high-side switch unit, and a low-side switch unit. The detection circuit includes: a detection power module, a first switch module, a second switch module, a first detection module, a second detection module, and a control module. The control module is configured to obtain an electrical signal at a third end of the first detection module and/or an electrical signal at a second end of the second detection module; and determine, based on the electrical signal at the third end of the first detection module and/or the electrical signal at the second end of the second detection module, whether a fault occurs in the drive circuit of the electrical control device. In this implementation, fault diagnosis can be performed on the drive circuit of the electrical control device.