Voltage Divider Fault Detection for Battery-Converter Isolation
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Solution Overview
Problem
Existing photovoltaic systems face challenges in detecting contact or ground faults in battery packs and converters, which can lead to damage and safety risks such as overcurrent and potential fires.
Innovation Solution
A fault detection device comprising resistors, sensing circuits, and processors is used to measure voltage changes at nodes between resistors and compare these changes with reference levels to detect contact or ground faults, utilizing amplifiers and filters to process signals and block connections when faults are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fault detection device is added to detect contact faults in battery packs and converters, then system safety is improved, but device complexity increases
Solution Approach 1:
The fault detection device merges the detection of contact faults between batteries and converters into a single integrated system. The processor unit combines multiple detection functions (voltage measurement, fault analysis, safety control) into one device, eliminating the need for separate detection systems for each component while maintaining comprehensive safety monitoring.
Solution Approach 2:
The fault detection device is designed with multi-functionality to detect various types of faults including contact faults between batteries and converters, ground faults, and insulation issues. The single device performs multiple detection tasks across different system components (battery pack, converter, grid connection), reducing overall system complexity while improving reliability through comprehensive monitoring.
2Measurement precision
If voltage measurement and signal processing circuits are added to detect faults, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The circuit configuration performs preliminary signal conditioning before measurement. Resistors are pre-arranged in specific configurations (including delta-wye transformation circuits) to prepare the voltage signals for accurate measurement. The amplifier circuits are pre-configured with appropriate gain settings to amplify weak fault signals before they reach the processor, ensuring high measurement precision without requiring complex post-processing circuits.
Solution Approach 2:
The patent introduces intermediary components such as resistor networks and amplifier circuits that mediate between the raw voltage signals from the system and the processor. These intermediaries condition and transform the signals into a suitable form for detection, improving measurement precision while keeping the overall circuit design manageable through modular signal processing stages.
Data Source
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AI summary
A fault detection device according to an embodiment of the present invention comprises: a plurality of resistors which are connected in series between both input terminals of a converter; a sensing circuit which measures a first voltage at one of nodes between the plurality of resistors; and a processor which detects a fault by using changes in the first voltage.