Battery Insulation Monitoring Circuit for Dormant Vehicle Detection
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Solution Overview
Problem
Existing insulation monitoring circuits for vehicle batteries are unable to perform real-time monitoring when the vehicle is dormant, as they rely on control signals from the Battery Management System (BMS) that are not available in this state.
Innovation Solution
The proposed insulation monitoring circuit includes a voltage-to-frequency conversion circuit, an RC series circuit, a first peak sampling circuit, and an alarm trigger module. This circuit obtains power from the vehicle battery and operates independently of the BMS, allowing for real-time insulation monitoring by sampling voltage signals and adapting low-frequency pulse signals to the vehicle battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the balanced bridge method with software-controlled bridge arms is used, then insulation values can be calculated, but real-time monitoring is not possible when the vehicle is dormant and BMS is not working
Solution Approach 1:
The insulation monitoring circuit is designed to operate autonomously without requiring BMS control signals. It uses its own oscillation circuit to generate test signals and automatically switches bridge arms through hardware control circuits, enabling self-service operation during vehicle dormancy when BMS is not working.
Solution Approach 2:
The patent replaces the software-controlled switching mechanism with a hardware-based automatic switching system. The oscillation circuit generates periodic signals that automatically trigger bridge arm switching through hardware control circuits, eliminating dependence on software and BMS operation.
2Reliability
If the insulation monitoring circuit operates independently without BMS control signals, then real-time monitoring during dormancy is enabled, but the circuit complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated circuits: the oscillation circuit, bridge arm control circuits, and signal processing functions are merged into a unified hardware system. This integration reduces the number of separate components and simplifies the overall circuit structure despite the enhanced functionality.
Solution Approach 2:
The oscillation circuit generates periodic test signals at fixed frequencies to sequentially activate different bridge arms. This periodic action enables automatic switching and measurement cycles without requiring complex control logic, simplifying the circuit design while maintaining real-time monitoring capability.
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 solution enables continuous, real-time insulation monitoring of vehicle batteries, even when the vehicle is dormant, thereby enhancing safety by preventing electrical leakage accidents.
Implementation Method 1
a voltage-to-frequency conversion circuit, configured for converting a voltage signal at an input terminal of the voltage-frequency conversion circuit into a low-frequency pulse signal
Implementation Method 2
an RC series circuit; wherein the RC series circuit is formed by a resistor and a capacitor connected in series
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 of the voltage signal
Implementation Method 4
the voltage jump detection submodule comprises a differential circuit; the differential circuit is connected to the resistor rear end in the RC series circuit, and is configured for differentiating the voltage signal of the resistor rear end
Data Source
Figure 1~2
Figure 3~4
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.