Transformer Overcurrent Protection Circuit for Delayed Fault Identification
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Solution Overview
Problem
In power supply systems with transformers, large communication delays between the primary and secondary sides of the transformer hinder effective identification of faults, leading to reduced stability and reliability.
Innovation Solution
An overcurrent protection circuit that includes a transformer, sampling circuits, and processors to collect and analyze current and voltage signals, allowing for timely identification and protection against faults, even with large communication delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage difference between the primary side and the secondary side of the transformer is low, then an isolator with a short delay can be used to meet isolation communication requirements, but when a fault occurs and communication delay is large (10 μs or even greater), the fault cannot be effectively identified
Solution Approach 1:
The patent segments the overcurrent protection function into two parts: hardware-level current limiting (OCP1 and OCP2 circuits) and software-level fault identification (processor analyzing sampling signals). This segmentation allows the system to operate effectively regardless of communication delay magnitude, as the hardware provides immediate protection while the software identifies fault types after receiving sampled data.
Solution Approach 2:
The patent implements preliminary action by having the sampling circuits continuously collect current and voltage signals before faults occur, and storing these sampled signals in the processor. When a fault occurs, the processor can immediately analyze the pre-captured sampling signals to identify the fault type, eliminating the need for real-time communication during the fault event and thus overcoming communication delay issues.
2Reliability
If different logic protection is used for different faults (winding short circuit vs. output short circuit), then protection effectiveness is improved, but system complexity increases due to need for multiple OCP circuits and delay management
Solution Approach 1:
The patent applies universality by designing a single OCP circuit that serves multiple functions: it limits current for both primary-side and secondary-side faults, and the same sampling circuits collect signals for identifying different fault types. The processor universally analyzes sampling signals to determine whether the fault is a winding short circuit, output short circuit, or surge current, eliminating the need for separate dedicated circuits for each fault type.
Solution Approach 2:
The patent introduces sampling circuits as intermediaries between the hardware OCP circuits and the processor. These sampling circuits capture current and voltage signals and transfer them to the processor for analysis, serving as a mediator that enables the processor to identify fault types without requiring direct complex hardware interfaces or real-time communication during faults, thus simplifying the overall system architecture.
Data Source
AI summary
An overcurrent protection circuit of a power supply system and a power conversion apparatus. In embodiments, only one overcurrent protection hardware circuit needs to be disposed, so that when a fault occurs in the power supply system, a type of the fault can be identified, and corresponding protection can be performed. This improves reliability of the power supply system.