DC/DC Converter Residual Current Isolation for Flexible Protection
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Solution Overview
Problem
Conventional power supply systems face inflexible protection methods that lead to system shutdowns when residual currents exceed thresholds, posing safety risks and operational inefficiencies.
Innovation Solution
A power supply system with modular residual current detection and control mechanisms, allowing selective disconnection of strings or circuits based on threshold exceedance, using controllers and disconnect switch apparatuses to isolate faulty modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inverter is directly disconnected from the alternating current power grid when residual current exceeds threshold, then safety is protected, but the power supply system stops working and flexibility is reduced
Solution Approach 1:
The patent divides the power supply system into multiple independent strings (first string, second string, etc.), each with its own residual current detection circuit and controller. When a fault is detected in one string, only that specific string is disconnected while other strings continue to operate. This segmentation allows selective protection without complete system shutdown, resolving the contradiction between safety and operational flexibility.
2Reliability
If the entire power supply system is shut down to eliminate residual current, then safety is ensured, but productivity and operational continuity are reduced
Solution Approach 1:
The patent extracts and isolates the faulty string from the overall power supply system by controlling disconnection of only the affected string rather than the entire system. The controller receives residual current detection results and selectively disconnects only the problematic string, allowing the remaining healthy strings to continue supplying power to the alternating current power grid, thus maintaining productivity while ensuring safety.
3Reliability
If residual current detection is performed at the inverter output, then system-level protection is achieved, but the protection response is slow and less precise
Solution Approach 1:
The patent implements preliminary residual current detection at the input end of each string, before the power flows through the inverter. Each string has its own detection circuit that continuously monitors residual current and immediately triggers disconnection of that specific string when a fault is detected. This preliminary detection approach enables faster response time compared to detecting at the inverter output, as the fault is identified and isolated at its source before affecting the entire system.
Data Source
AI summary
A power supply system includes at least one group of power supply modules. The power supply module includes a first string, a first residual current detection circuit, an inverter circuit, and a first controller. The first residual current detection circuit is connected between the first string and an input end of the inverter circuit, and an output end of the inverter circuit is connected to an alternating current power grid. When a first residual current value detected by the first residual current detection circuit is greater than a first preset residual current threshold, the first controller controls the first string to be disconnected from the inverter circuit, or controls the inverter circuit to be disconnected from the alternating current power grid.