EV Driver Circuit Fault Detection for Contactor Coils
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Solution Overview
Problem
Existing driver circuits for electric vehicles lack effective diagnostic methods to identify fault conditions in contactor coils when they are de-energized, leading to potential operational issues and reduced reliability.
Innovation Solution
A driver circuit with a microprocessor-controlled system of voltage drivers and feedback mechanisms that perform diagnostic algorithms to determine undesired voltage levels in main, grounding, and pre-charge contactor coils, setting status flags for fault conditions and storing them in memory, ensuring proper operation and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driver circuit operates contactor coils without diagnostic monitoring, then the circuit structure remains simple, but fault detection capability is insufficient leading to reduced reliability
Solution Approach 1:
The patent implements diagnostic algorithms that execute before contactor coil operation to pre-detect potential faults. The microprocessor performs voltage level checks and status flag evaluations in advance, identifying undesired conditions before they lead to operational failures, thereby improving reliability without requiring complex real-time monitoring hardware
Solution Approach 2:
The patent incorporates feedback mechanisms where the microprocessor continuously monitors voltage levels on feedback lines connected to contactor coils. Status flags are set based on measured voltage levels, and this information feeds back into the control logic to detect faults and prevent unsafe operation, enhancing fault detection capability through software-based monitoring rather than additional hardware complexity
2Ease of operation
If voltage drivers are added to control contactor coils, then contactor operation control is improved, but the device complexity increases
Solution Approach 1:
The patent employs a microprocessor that serves multiple functions: it controls voltage drivers for contactor coil operation, executes diagnostic algorithms, measures voltage levels, sets status flags, and manages memory storage. This multi-functional approach consolidates what would otherwise require separate dedicated circuits into a single programmable controller, improving ease of operation while minimizing the increase in device complexity
Solution Approach 2:
The patent replaces potential mechanical or hardwired control mechanisms with a software-based control system. The microprocessor uses programmable logic to control voltage drivers and interpret feedback, substituting flexible software control for rigid hardware wiring, thereby simplifying the overall system architecture while maintaining precise control capability
Data Source
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AI summary
A driver circuit and a diagnostic method are provided. The circuit includes a first voltage driver having a first output line electrically coupled to a main contactor coil of a main contactor. The circuit further includes a microprocessor that measures a first voltage on a first voltage feedback line if the main contactor coil is not energized. The microprocessor measures a second voltage on a second voltage feedback line if the main contactor coil is not energized. The microprocessor sets a status flag equal to a fault condition value if the first voltage is greater than a threshold voltage value. Also, the microprocessor sets the status flag equal to the fault condition value if the second voltage is greater than the threshold voltage value.