Multi-Stage DC Insulation Detection with Adaptive Bridge Balancing
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Solution Overview
Problem
Conventional insulation monitoring technologies based on balanced bridge theory are inadequate for multi-stage DC systems, leading to insulation calculation deviations and false alarms due to parallel connections of insulation detection devices from different manufacturers, which alter the actual resistance values of the balanced bridge.
Innovation Solution
A distributed insulation detection device for multi-stage DC systems, comprising an intelligent control module, sampling module, basic insulation combination module, and intelligent resistance switching network module, which adjusts resistance values to maintain balance and accuracy in insulation calculations, using both balanced and unbalanced bridge methods for fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional insulation detection devices are used for multi-stage DC systems, then the device structure becomes complex and adaptation is difficult, but the insulation detection function is limited
Solution Approach 1:
The insulation detection device is designed with a universal architecture that can detect insulation conditions for multiple DC voltage levels (first DC voltage and second DC voltage) simultaneously through a single device structure. The detection unit is configured to detect insulation between positive and negative power supply lines at different voltage levels, eliminating the need for separate detection devices for each voltage stage.
Solution Approach 2:
The detection method is segmented into distinct measurement stages: first detecting insulation at the first DC voltage level, then detecting insulation at the second DC voltage level, and finally determining overall insulation status by comparing both measurements. This segmentation allows the single device to handle multi-stage detection through sequential operation rather than requiring complex simultaneous multi-level measurement circuitry.
2Reliability
If insulation detection is performed for all power supply lines in multi-stage DC systems, then detection completeness is improved, but detection time increases
Solution Approach 1:
The insulation detection is performed periodically at different DC voltage levels in a systematic sequence. The device first detects insulation at the first voltage level, then at the second voltage level, creating a periodic detection cycle that ensures comprehensive coverage of all power supply lines while maintaining efficient timing through structured repetition rather than random or simultaneous measurement.
Solution Approach 2:
The device performs preliminary insulation detection at the first DC voltage level before proceeding to detect at the second voltage level. This preliminary action allows early identification of insulation issues at lower voltage stages, and the structured sequence enables optimization where detection can stop early if critical failures are found, reducing average detection time while maintaining completeness.
3Object-affected harmful factors
If conventional detection methods are used, then the detection principle is simple, but harmful factors such as battery discharge and power consumption are not avoided
Solution Approach 1:
The patent replaces conventional electrical measurement methods that require injecting test currents (which cause battery discharge and power consumption) with an alternative detection approach that measures insulation resistance by detecting voltage divisions across known resistance elements. This substitution eliminates the harmful effects of test current injection while achieving accurate insulation detection through voltage-based measurement instead of current-based measurement.
Solution Approach 2:
The detection method introduces intermediary resistance elements (first and second equivalent resistances) that serve as mediators between the power supply lines and the detection circuit. These intermediaries allow indirect measurement of insulation conditions without direct high-current testing, reducing power consumption and battery discharge by using voltage division through known resistances rather than direct current injection into the battery system.
Data Source
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AI summary
Provided is a distributed insulation detection device for a multi-stage DC system. A basic insulation combination module is configured to detect a ground insulation fault of the multi-stage DC system, a sampling module is configured to collect voltage data and/or leakage current data of the multi-stage DC system, to transmit the collected voltage data and/or the leakage current data to an intelligent control module for data processing, to control a resistance value of the basic insulation combination module and a resistance value of an intelligent resistance switching network module, so as to adjust a total balance resistance of the distributed insulation detection device for the multi-stage DC system.