EV Driver Circuit Self-Diagnosis for Shorted Voltage Faults
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Solution Overview
Problem
Existing driver circuits for electric vehicles lack effective diagnostic methods to determine when a first voltage driver is shorted to a high voltage and a second voltage driver has low electrical current flowing through, which can lead to operational failures and safety issues.
Innovation Solution
A driver circuit and diagnostic method that utilize a microprocessor to generate pulse width modulated signals, measure voltages, and determine filtered voltage and current values to set diagnostic flags, allowing for the detection of voltage driver issues and subsequent de-energization of the contactor coil when thresholds are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a driver circuit operates without diagnostic monitoring, then the device complexity is reduced, but the reliability decreases due to undetected short circuits and low current conditions
Solution Approach 1:
The driver circuit performs self-diagnosis by monitoring its own output voltage and current through sense lines connected to the microprocessor. The system detects faults internally without requiring external diagnostic equipment, allowing the circuit to monitor itself and trigger protective actions when abnormalities are detected.
Solution Approach 2:
The circuit implements feedback mechanisms through voltage sense lines that continuously monitor the output voltage and current of the voltage drivers. This feedback is fed back to the microprocessor, which compares the measured values against threshold values and triggers diagnostic flags when faults are detected, enabling real-time monitoring and response.
2Reliability
If voltage and current monitoring is continuously performed, then the reliability improves through early fault detection, but the use of energy increases due to continuous measurement operations
Solution Approach 1:
The microprocessor performs voltage and current measurements at periodic intervals during the operation of the driver circuit. Instead of continuous monitoring, the system samples the voltage sense lines and current sense lines at defined measurement cycles, reducing energy consumption while maintaining effective fault detection capability through regular monitoring.
Data Source
AI summary
A driver circuit and a diagnostic method are provided. The driver circuit includes a first voltage driver, a second voltage driver, and a microprocessor. The microprocessor generates a first pulse width modulated signal to induce the first voltage driver to output a second pulse width modulated signal to energize a contactor coil. The microprocessor sets a first diagnostic flag equal to a first value if a first filtered voltage value is greater than a first threshold value. The microprocessor sets a second diagnostic flag equal to a second value if a first filtered current value is less than a threshold value. The microprocessor stops generating the first pulse width modulated signal to de-energize the contactor coil if the first and second diagnostic flags are set equal to the first and second values, respectively.