MOSFET Switch Control for Surge-Era Reverse Conduction
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Solution Overview
Problem
Switch devices in electrical systems face excessive power dissipation and thermal stress during surge events due to large voltage drops, particularly when using wide-bandgap materials like silicon carbide (SiC), which can lead to thermal failure.
Innovation Solution
A system and method that uses a switch controller to selectively route current through either the third quadrant conduction path or the body diode conduction path based on measured conditions, such as source-drain voltage and temperature, to minimize voltage drop and power dissipation during surge events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wide-bandgap materials like silicon carbide are used in switch devices, then power conversion efficiency is improved, but thermal stress and power dissipation increase during surge events
Solution Approach 1:
The patent implements dynamic control of the switch device by adjusting the gate-source voltage in real-time based on operating conditions. During surge events, the controller dynamically modifies the voltage to transition between conduction modes, optimizing performance and reducing thermal stress. This dynamic adjustment allows the system to adapt to changing conditions rather than operating in a fixed state.
Solution Approach 2:
The patent changes the electrical parameters of the switch device by transitioning between third-quadrant conduction mode and body diode conduction mode. This parameter change is achieved by controlling the gate-source voltage to shift the operating point, thereby altering the conduction characteristics to better handle surge events and reduce power dissipation.
2Loss of energy
If the switch operates in third-quadrant conduction mode, then conduction losses are reduced, but voltage drop increases during high current surge events
Solution Approach 1:
The system dynamically transitions between third-quadrant conduction mode and body diode conduction mode based on real-time operating conditions. During high current surge events, the controller detects the increased current and voltage drop, then switches to body diode conduction mode where the voltage drop is better tolerated. This dynamic mode switching optimizes the trade-off between conduction losses and voltage drop.
Solution Approach 2:
The controller implements feedback control by monitoring the operating conditions of the switch device and adjusting the conduction mode accordingly. When voltage drop exceeds acceptable thresholds during surge events, the feedback mechanism triggers a transition to body diode conduction mode, ensuring stable operation despite increased voltage drop.
3Object-affected harmful factors
If the switch operates in body diode conduction path, then voltage drop is reduced during surge events, but conduction losses increase
Solution Approach 1:
The system operates in body diode conduction mode only during surge events when voltage drop is the critical constraint. During normal operating conditions, the system dynamically switches to third-quadrant conduction mode to minimize conduction losses. This time-dependent dynamic operation allows the system to prioritize voltage drop reduction when necessary while minimizing energy losses during normal operation.
Data Source
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AI summary
The application discloses the control of switches 104, such as metal-oxide semiconductor field effect transistors MOSFETs devices, during surge events 124, 308. The switch controllers 102 and methods 150 for operation thereof perform methods for providing driving signals 109 to the switch for adjusting the mode of operation based on the voltage and/or current thresholds e.g., 226, 236 as sensed by the system 100 and/or by the switch controller.