Insulation Detection Circuit Parameter Selection for Battery Safety

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Solution Overview

Problem

Existing insulation resistance detection methods for power batteries face challenges in accurately calculating insulation resistance within a varying resistance range, leading to potential high voltage safety issues due to insufficient detection accuracy.

Innovation Solution

A parameter selection method and apparatus for an insulation detection circuit that includes a signal generation module, voltage division module, isolation module, and processor, which determines an allowable injection frequency range for a low-frequency AC signal based on the predetermined resistance range and calculation cycle, allowing for improved accuracy by selecting an optimal output frequency that maximizes the variation of the voltage signal between the isolation module and voltage division resistor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional AC signal injection method is used to detect insulation resistance, then the detection can be performed with a simple circuit structure, but the voltage signal variation is insufficient when insulation resistance varies within a resistance range, leading to reduced measurement precision

Engineering Contradiction:
Improveinsulation resistance measurement precisionVSAvoidsignal generation module complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the output frequency of the signal generation module based on the detected insulation resistance value. When insulation resistance is high, the frequency is lowered to increase voltage signal variation across the isolation module and voltage division resistor, thereby improving measurement precision without requiring complex circuit modifications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the signal generation frequency adaptive rather than fixed. The system continuously monitors insulation resistance and adjusts the AC signal frequency in real-time, allowing the detection circuit to optimize its operating parameters dynamically based on the actual insulation conditions, thus achieving high precision across varying resistance ranges

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the output frequency of the signal generation module is fixed, then the device operation is simple, but the voltage signal variation between the isolation module and voltage division resistor is insufficient when insulation resistance varies, reducing detection accuracy

Engineering Contradiction:
Improvevoltage signal detection accuracyVSAvoidfrequency adjustment operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies self-service by implementing an automatic frequency adjustment mechanism where the signal generation module autonomously changes its output frequency based on feedback from the insulation resistance detection. The system self-regulates the frequency to optimize voltage signal variation, eliminating the need for manual frequency adjustment and maintaining ease of operation while improving detection accuracy

Inventive Principle:
Principle #25Self-service

3Measurement precision

If a low frequency AC signal is injected to increase voltage signal variation, then the measurement precision improves, but the detection time increases due to the longer period required for accurate measurement

Engineering Contradiction:
Improveinsulation resistance calculation accuracyVSAvoidresistance calculation cycle time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent resolves this contradiction through dynamic frequency adjustment. Instead of using a consistently low frequency that would slow down detection, the system adaptively selects frequency values based on current insulation resistance levels. This allows the system to achieve sufficient voltage signal variation for accurate measurement while minimizing the measurement time by using the lowest necessary frequency at any given moment

Inventive Principle:
Principle #15Dynamics

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

This approach enhances the calculation accuracy of insulation resistance by ensuring significant variation of the voltage signal as the insulation resistance changes within a predetermined range, thereby improving detection precision and ensuring safety.

Implementation Method 1

an alternating current (AC) source is applied to inject an AC signal into the power battery under test

Methodology Applied
Scientific EffectAlternating current (AC) signal generation:

Implementation Method 2

a voltage division resistor and an isolation module are arranged in turn between the AC source and the power battery under test

Methodology Applied
Scientific EffectVoltage division: Ohm's Law

Implementation Method 3

an isolation module...configured to isolate a high-voltage signal of the power battery under test

Methodology Applied
Scientific EffectElectrical isolation:

Data Source

PatentEP3521839B1Parameter selection method and apparatus, and storage medium for insulation detection circuit
Publication Date: 2021.04.14 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
  • EP3521839B1 patent drawingFigure 1
  • EP3521839B1 patent drawingFigure 2
  • EP3521839B1 patent drawingFigure 3

AI summary

The present disclosure provides a parameter selection method, apparatus, and computer readable storage medium for an insulation detection circuit. The parameter selection method includes determining (601) an allowable injection frequency range of an AC signal to be injected, according to a predetermined resistance range of an insulation resistance of the power battery under test and a predetermined resistance calculation cycle of the insulation resistance; and selecting (602) an output frequency of the signal generation module (Y1) according to a lowest frequency to be generated by the signal generation module (Y1) and the allowable injection frequency range. With the technical solutions of the embodiments of the present disclosure, a relatively large variation of the voltage signal between the isolation module (G1) and the voltage division resistor (R1) can be detected when the insulation resistance changes within a predetermined resistance range, and thus the calculation accuracy of the insulation resistance can be improved.