Solid-State Circuit Interrupter With DESAT Trip and Isolation
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Solution Overview
Problem
Solid state circuit interrupters have not fully utilized their capabilities for fast tripping and face safety and wellness concerns compared to conventional mechanical circuit interrupters, indicating a need for improved design and functionality.
Innovation Solution
A circuit interrupter design that includes a current sensor, solid state switch module, gate driver with desaturation function, and analog trip circuit to quickly interrupt current flow, along with separable contacts and an electronic trip unit for galvanic isolation, allowing for fast and controlled switching and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If solid state components are used to switch current, then tripping speed is improved, but safety and wellness concerns worsen
Solution Approach 1:
The patent introduces separable contacts as an intermediary mechanical switching element that works in conjunction with the solid state switch module. The separable contacts provide a physical gap for arc extinction and galvanic isolation, while the solid state components provide fast detection and control. This hybrid approach combines the fast response of solid state electronics with the safety benefits of mechanical isolation.
Solution Approach 2:
The patent replaces conventional purely mechanical switching mechanisms with a solid state switch module controlled by electronic sensing and control circuitry. The current sensor, gate driver, and control logic provide faster and more precise control compared to mechanical trip mechanisms, while the separable contacts maintain the necessary safety functions.
2Speed
If solid state switch module is used, then current interruption speed is improved, but risk of arcing worsens
Solution Approach 1:
The patent segments the current interruption function into two distinct stages: The solid state switch module provides fast initial current interruption by switching off the semiconductor devices, while the separable contacts provide a physical gap for complete arc extinction. This segmentation allows each component to optimize its function - electronic speed and mechanical safety.
Solution Approach 2:
The control system uses the desaturation function to detect solid state switch stress conditions before failure occurs. When the desaturation function activates, it signals that the solid state switch is approaching its current handling limits, prompting the control system to initiate the tripping sequence that opens the separable contacts, preventing arcing and damage before they can occur.
3Reliability
If desaturation function is added to gate driver, then protection capability is improved, but device complexity worsens
Solution Approach 1:
The patent merges the desaturation detection function directly into the gate driver circuitry. The gate driver not only controls the solid state switch but also monitors its health status through the desaturation function. This integration eliminates the need for separate protection circuits and simplifies the overall device architecture while maintaining comprehensive protection capabilities.
Data Source
AI summary
A circuit interrupter including a current sensor having a normal sensor output and an over current detection output, a solid state switch module structured to have a closed state to allow current to flow through the circuit interrupter and an open state to interrupt current flowing through the circuit interrupter, a gate driver structured to control the solid state switch module including a desaturation function output, wherein the gate driver is structured to cause the solid state switch module to interrupt current flowing through the circuit interrupter when the DESAT function output changes to the on state, and an electronic trip circuit structured to output a trip signal to the gate driver when the normal sensor output reaches a first threshold level or the overcurrent detection output changes to the on state.