Insulation Resistor Detection Circuit for Real-Time Fault Sensing
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Solution Overview
Problem
Existing insulation resistor detection methods for high-voltage power supply systems in electric vehicles are unable to timely detect faults, leading to potential electric shocks and unsafe system operation due to interference and fixed period-based detection methods.
Innovation Solution
A circuit and method utilizing a state control unit, voltage division branches, and a processor to dynamically switch between charging and discharging states of capacitors connected between the power supply electrodes and ground, allowing for real-time detection of insulation resistor changes and accurate resistance value calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alternating-current signal injection method is used to detect insulation resistor, then detection can be performed, but the injected alternating-current signal causes interference to the high-voltage power supply system and affects normal working of the system
Solution Approach 1:
The patent introduces a detection circuit as an intermediary system that uses voltage division branches and capacitors to indirectly measure insulation resistor values. Instead of injecting AC signals directly into the power supply system, the detection circuit connects through isolated pathways (using capacitors C1 and C2 connected to ground) to measure voltages U1 and U2, which are then processed to calculate insulation resistance. This intermediary approach enables detection without causing interference to the normal operation of the high-voltage power supply system.
2Measurement precision
If external resistor connection method with fixed period detection is used, then insulation resistor values can be calculated, but the fixed period detection cannot detect faults in time when insulation resistor is faulty
Solution Approach 1:
The patent implements a feedback mechanism where the processor continuously monitors the voltages U1 and U2 from the voltage division branches and dynamically adjusts the switching states of switches K1 and K2. The system compares measured values with threshold values and automatically triggers alarms or protective actions when insulation resistance drops below safe levels. This closed-loop feedback enables real-time fault detection rather than relying on fixed periodic checks, significantly reducing the time delay in detecting insulation failures.
Solution Approach 2:
The detection system transitions from static fixed-period detection to dynamic adaptive detection. The processor dynamically controls the switching states of K1 and K2 based on real-time voltage measurements and system conditions. The detection frequency and switching timing are adjusted according to the actual insulation status, allowing the system to respond immediately to changing conditions and detect faults as they occur rather than waiting for the next predetermined detection cycle.
3Measurement precision
If switch and series resistors are connected between positive and negative electrodes for external resistor connection method, then insulation resistor values can be solved through equations, but the system cannot alarm or process faults in time
Solution Approach 1:
The patent replaces the manual calculation and fixed-period measurement approach with an automated electronic measurement and processing system. The processor automatically performs voltage measurements, calculates insulation resistance values in real-time, compares results against thresholds, and triggers alarms or protective actions without human intervention or fixed timing delays. This substitution of automated electronic systems for manual/mechanical processes dramatically improves fault response speed while maintaining accurate insulation resistance determination.
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 timely and accurate detection of insulation resistor faults, ensuring safe operation of high-voltage power supply systems by quickly identifying resistance value deviations and preventing electric shocks.
Implementation Method 1
a first capacitor C1 and a second capacitor C2, where the first capacitor C1 is configured to be charged when the state control unit is in the first state and discharge electricity when the state control unit is in the second state, and the second capacitor C2 is configured to be charged when the state control unit is in the second state and discharge electricity when the state control unit is in the first state
Data Source
AI summary
This application provides an insulation resistor detection circuit, which includes a state control unit, which is connected between a positive electrode and a negative electrode of a power supply of a to-be-detected apparatus; a first voltage division branch that is connected in parallel to a first capacitor to obtain a first voltage waveform, a second voltage division branch that is connected in parallel to a second capacitor to obtain a second voltage waveform; and a processor that is connected to the state control unit, the first voltage division branch, and the second voltage division branch; determines a next switching moment based on the first voltage waveform and the second voltage waveform that are at a current moment; and control, at the next switching moment, the state control unit to switch a state.