Insulation Fault Detection Circuit for Electric Vehicle Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current insulation monitoring systems in electric vehicles fail to detect insulation faults between the battery and mechanical ground, leading to potential short circuits and safety risks, as they cannot accurately determine fault polarity, amplitude, or measure insulation without excessive electricity consumption or high costs.
Innovation Solution
A device with first and second input terminals connected to the battery terminals, featuring resistive dipoles and a detection circuit that alternately opens and closes a switch to measure voltages across resistive dipoles, determining insulation fault amplitude and polarity, with resistive dipoles having specific resistance ratios and a detection circuit controlling the switch to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional insulation monitoring systems are used, then insulation faults can be detected, but the systems cannot accurately determine fault polarity, amplitude, or measure insulation without excessive electricity consumption or high costs
Solution Approach 1:
The patent implements periodic action by alternately opening and closing a switch in the monitoring circuit at regular intervals. This allows the system to measure insulation parameters in discrete measurement cycles rather than continuous operation, significantly reducing electricity consumption while maintaining accurate detection capability. The periodic switching enables multiple measurement configurations to be tested sequentially.
Solution Approach 2:
The patent applies parameter changes by varying the circuit configuration through switch operations, changing the resistance values and measurement topologies dynamically. By altering circuit parameters (switch states, resistor connections) periodically, the system can extract multiple insulation parameters (polarity, amplitude, resistance) from a single monitoring device, achieving high measurement precision without requiring multiple always-active sensors that would consume excessive power.
2Measurement precision
If conventional insulation monitoring systems are used, then insulation faults can be detected, but the systems cannot accurately determine fault polarity or amplitude
Solution Approach 1:
The patent implements universality by designing a single monitoring circuit that performs multiple functions: detecting insulation faults, determining fault polarity, measuring fault amplitude, and calculating insulation resistance. Through clever circuit design with alternating switch operations, one universal device replaces what would traditionally require multiple specialized sensors and measurement systems, reducing overall device complexity while enhancing measurement precision.
Solution Approach 2:
The monitoring system applies self-service by using its own internal switch and resistor network to generate the necessary measurement conditions. The system alternates between different measurement configurations using its built-in components, eliminating the need for external test equipment or complex external circuitry. This self-contained approach determines both polarity and amplitude using only the internal monitoring circuitry.
3Measurement precision
If high-precision insulation monitoring is implemented, then accurate fault detection is achieved, but the cost increases
Solution Approach 1:
The patent employs cheap short-living objects by using simple, low-cost resistive elements and switching components that can be manufactured economically. Rather than using expensive precision instruments or complex sensor arrays, the system relies on basic electronic components (resistors, switches, voltage dividers) that are inexpensive and easily manufactured. The measurement accuracy is achieved through clever circuit configuration rather than expensive hardware.
Solution Approach 2:
The monitoring system applies copying by creating multiple virtual measurement configurations through switch operations on a single physical circuit. Instead of requiring multiple physical sensors or measurement paths, the system copies the measurement function through temporal multiplexing - the same physical components are reconfigured periodically to simulate multiple different measurement setups, achieving comprehensive monitoring accuracy at low cost.
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 device effectively detects insulation faults, determines fault polarity, and measures fault amplitude, ensuring safety by preventing short circuits while maintaining low electricity consumption and cost-effectiveness, suitable for high-voltage battery systems in electric vehicles.
Implementation Method 1
measuring the voltage across the terminals of the third dipole when the switch is open and when the switch is closed; determine the amplitude of an insulation fault according to the voltages measured
Data Source
Figure 1~3
Figure 4~6
Figure 7~10
AI summary
The invention relates to a device (4) for detecting an insulation fault of a direct voltage source that can induce electrocution, comprising: first and second input terminals (-Vbat, +Vbat) for the voltage source; first and third resistive dipoles (41, 43) connected in series between an electric ground (91) and the second input terminal (+Vbat), the first resistive dipole (41) having a resistance at least ten times higher than that of the third dipole (43); a second resistive dipole (42) and a switch (45) connected in series between the first input terminal (-Vbat) and the electric ground (91); and a detection circuit (44) connected to the terminals of the third dipole (43), designed to alternately open and close said switch, measure the voltage at the terminals of the third dipole, and determine the amplitude of an insulation fault according to the measured voltages.