Battery Insulation Monitoring Circuit for Dormant Vehicle Leakage Detection
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Solution Overview
Problem
Existing insulation monitoring systems for vehicle batteries are unable to perform real-time monitoring during vehicle dormancy due to the battery management system's inability to control bridge arms, posing safety risks due to potential electric leakage.
Innovation Solution
An insulation monitoring circuit that includes a voltage-to-frequency conversion circuit, an RC series circuit, a first peak sampling circuit, and an alarm trigger module, which operates independently of the battery management system to inject a low-frequency pulse signal into the vehicle battery system, sample voltage signals, and output alarm-triggering signals based on detected voltage jumps, enabling real-time insulation monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software-controlled bridge arms are used for insulation monitoring, then insulation values can be calculated, but real-time monitoring is not possible during vehicle dormancy
Solution Approach 1:
The insulation monitoring circuit operates autonomously using hardware-based automatic bridge switching. The system self-activates during vehicle dormancy without requiring BMS intervention, with the bridge arms automatically switching states based on control signals generated within the monitoring circuit itself, enabling continuous real-time monitoring independent of the main control system
Solution Approach 2:
The patent replaces software-controlled switching with hardware-based automatic switching mechanisms. The bridge arm switching is achieved through dedicated hardware circuits that automatically respond to voltage changes, eliminating dependence on software execution and enabling operation during dormancy when the BMS is inactive
2Ease of manufacture
If the BMS controls bridge arm closing, then insulation monitoring can be implemented, but the system cannot monitor during dormancy when BMS is inactive
Solution Approach 1:
The monitoring function is segmented into an independent hardware-based insulation monitoring circuit that operates separately from the BMS. This dedicated circuit handles bridge arm switching and insulation measurement autonomously, allowing it to function during both active and dormant states of the vehicle
Solution Approach 2:
The hardware monitoring circuit is designed to be always ready and automatically activates without waiting for BMS commands. The circuit preemptively handles monitoring tasks during dormancy, ensuring continuous protection without requiring preliminary activation by the BMS
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
Enables stable and reliable real-time insulation monitoring of vehicle batteries without relying on the battery management system, ensuring safety by detecting insulation issues and triggering alarms as needed, even when the vehicle is dormant.
Implementation Method 1
a voltage-to-frequency conversion circuit, configured for outputting a low-frequency pulse signal
Implementation Method 2
injecting the low-frequency pulse signal into a high-voltage system connected to the vehicle battery via the RC series circuit
Implementation Method 3
the first peak sampling value is configured for sampling a voltage signal of a resistor rear end in the RC series circuit, and transferring a first peak detection signal indicative of the peak value
Implementation Method 4
the alarm trigger module is configured for processing the voltage signal of the resistor rear end in the RC series circuit, and outputting an alarm-triggering signal
Data Source
AI summary
A vehicle and an insulation monitoring circuit for vehicle battery, the insulation monitoring circuit acquiring power from the vehicle battery and comprising a voltage-to-frequency conversion circuit (11), an RC series circuit (12), a first peak sampling circuit (13), and an alarm trigger module (14); the voltage-to-frequency conversion circuit (11) outputs a low-frequency pulse signal and injects same via the RC series circuit (12) into a high-voltage system connected to the vehicle battery; the first peak sampling circuit (13) performs sampling on a voltage signal of a resistor rear end in the RC series circuit (12) and feeds back same to the voltage-to-frequency conversion circuit (11), such that the outputted low-frequency pulse signal is adapted to the vehicle battery; and the alarm trigger module (14) performs processing on the voltage signal of the resistor rear end in the RC series circuit (12) and outputs an alarm trigger signal. The entire insulation monitoring process can be implemented without the control of the vehicle BMS, and real-time insulation monitoring can be implemented as long as the vehicle battery is intact; in addition, the use of a closed-loop output low-frequency pulse signal enables adaption to the capacitance between the high and low voltage circuits of the vehicle battery, thereby achieving stable and reliable insulation monitoring.