Insulation Detection Circuit Common Ground Signal Accuracy
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Solution Overview
Problem
Existing insulation detection circuits for power battery packs face accuracy issues due to the introduction of new interference signals by isolation units, which are necessary to isolate high voltage signals, leading to decreased accuracy in sampled signals.
Innovation Solution
The proposed solution involves connecting the power battery pack and sampling unit in common ground, eliminating the need for an isolation unit, thereby improving signal accuracy by allowing the positive and negative sampling units to operate in low voltage common-ground-connection, which reduces interference and simplifies the circuit structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an isolation unit is introduced to isolate high voltage grounded signal, then the high voltage signal is isolated from the sampling unit, but a new interference signal is introduced and measurement accuracy decreases
Solution Approach 1:
The patent extracts and removes the isolation unit from the circuit configuration. By eliminating this component, the patent eliminates the source of interference signals while maintaining the necessary signal isolation through alternative means (common ground connection), thereby resolving the contradiction between signal isolation and measurement accuracy.
Solution Approach 2:
The patent introduces a common ground connection as an intermediary mechanism to achieve signal isolation without requiring an isolation unit. This common ground serves as a mediator that allows the sampling unit to reference the same ground potential as the power battery pack, eliminating interference while maintaining isolation.
2Reliability
If an isolation unit is used to isolate high voltage signal, then high voltage grounded signal is isolated, but circuit complexity increases
Solution Approach 1:
The patent removes the isolation unit from the circuit, directly reducing component count and circuit complexity while maintaining the necessary signal isolation function through the common ground connection approach.
Solution Approach 2:
The patent merges the grounding references of the power battery pack and sampling unit into a common ground connection. This consolidation eliminates the need for separate isolation units and reduces circuit complexity by unifying the reference potential.
3Reliability
If non-common-ground-connection is used for power battery pack and sampling unit, then high voltage signal isolation is achieved, but new interference signals are introduced
Solution Approach 1:
The patent uses a common ground connection as an intermediary to achieve both high voltage isolation and eliminate interference. The common ground acts as a mediator that allows the sampling unit to reference the same potential as the power battery pack negative electrode, thereby isolating high voltage signals while preventing interference.
Data Source
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AI summary
An insulation detection circuit, detection method, and battery management system are disclosed in the present disclosure. The insulation detection circuit includes a positive sampling unit (F1), a negative sampling unit (F2), a positive sampling point (S1), a negative sampling point (S2), a reference voltage terminal (GND), and a processor (C1). A first end of the positive sampling unit (F1) is connected with positive electrode of the power battery pack to be measured. A second end of the positive sampling unit (F1) is connected with the reference voltage terminal (GND) and the positive sampling point (S1). A first end of the negative sampling unit (F2) is connected with negative electrode of the power battery pack to be measured. A second end of the negative sampling unit (F2) is connected with the reference voltage terminal (GND) and the negative sampling point (S2). The processor (C1) is connected with the positive sampling point (S1) and the negative sampling point (S2). The processor (C1) is configured to obtain a positive insulation resistance value and a negative insulation resistance value of the power battery pack to be measured based on the positive sampled signal and the negative sampled signal. The insulation detection circuit provided in the embodiments of the present disclosure may improve the detection accuracy of the insulation resistance values of the power battery pack. [FIG. 1]