Solid-State Fuse Control Circuits for Fault Type Differentiation
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Solution Overview
Problem
Existing high-voltage electrical systems in electrified vehicles lack effective resettable fuses to manage overcurrent and voltage drop conditions, which can lead to faults and damage, and current solutions do not distinguish between short circuit faults and overcurrent events effectively.
Innovation Solution
A solid-state fuse device with a voltage-controlled switching device, current sensor, and latch system that transitions from a closed to an open state when overcurrent or voltage drop thresholds are exceeded, allowing for differentiation between short circuit faults and overcurrent events, and includes delay circuitry to distinguish inrush currents from faults, using components like IGBTs, MOSFETs, or GaN FETs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a solid-state fuse device uses multiple control circuits to distinguish between short circuit faults and overcurrent events, then measurement precision and fault differentiation capability are improved, but device complexity increases
Solution Approach 1:
The fuse device is divided into multiple independent control circuits: a first control circuit monitors overcurrent conditions using a current sensor, while a second control circuit monitors voltage drop across the fuse element. Each control circuit independently evaluates its respective parameter against predefined thresholds and can independently trigger the opening of the switching device. This segmentation allows precise fault differentiation without requiring a single complex control system.
Solution Approach 2:
The patent introduces intermediary sensing mechanisms (current sensor and voltage drop sensor) that act as mediators between the physical fault conditions and the control decision-making process. These sensors convert physical quantities (current, voltage) into measurable signals that the control circuits can process, enabling accurate fault detection while keeping the control logic relatively simple and modular.
2Reliability
If the fuse device opens immediately when thresholds are exceeded, then protection speed and reliability are improved, but false tripping on inrush currents increases
Solution Approach 1:
The control circuits are configured with threshold comparison logic that evaluates whether measured parameters (current, voltage drop) exceed predefined thresholds before triggering the opening action. This preliminary evaluation allows the system to distinguish between normal inrush currents (which remain below thresholds) and actual fault conditions (which exceed thresholds), preventing false tripping while maintaining rapid protection when genuine faults occur.
3Ease of operation
If the fuse device allows reset functionality, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The latch circuit is designed to automatically reset the switching device when the fault condition is resolved and parameters return to normal ranges. The system monitors the fault conditions continuously and autonomously determines when resetting is safe, eliminating the need for manual intervention or complex external control systems while providing convenient reset functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solid-state fuse device effectively prevents current flow during faults, allowing for safe operation and distinguishing between fault types, enabling efficient fault management and protection of the electrical system.
Implementation Method 1
a gate driver connected to the switch and configured to transition the switch from a closed state to an open state when at least one of an overcurrent measurement exceeds a predetermined overcurrent threshold or a voltage drop across the switch exceeds a predetermined saturation voltage threshold
Implementation Method 2
a current sensor connected between a traction battery and the switch, wherein the current sensor is configured to output an overcurrent signal indicative of an overcurrent measured by the current sensor
Data Source
AI summary
A solid-state fuse device includes a switch a gate driver connected to the switch and configured to transition the switch from a closed state to an open state when at least one of an overcurrent measurement exceeds a predetermined overcurrent threshold or a voltage drop across the switch exceeds a predetermined saturation voltage threshold.