SiC Relay Mesh Charging for Faster EV Power Switching
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Solution Overview
Problem
Current electric vehicle charging systems are limited by long charging times compared to fossil fuel vehicles, necessitating the development of high-speed switching devices capable of handling high power and voltage.
Innovation Solution
An electric vehicle charging apparatus utilizing a silicon carbide (SiC) MOSFET module with a relay mesh that allows users to select between fast and slow charging, featuring a SiC drive module with a digital isolator and charge pump, and a heat sink to reduce heat loss, enabling efficient high-speed switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If silicon-based MOSFETs or IGBT modules are used for charging, then the charging system can operate reliably, but the charging time becomes long due to higher switching losses
Solution Approach 1:
The patent changes the material parameter from silicon-based semiconductors to silicon carbide (SiC) MOSFETs. This material parameter change enables higher switching frequencies and lower switching losses, directly reducing charging time while maintaining system reliability. The SiC MOSFETs allow the charging system to operate efficiently at higher switching speeds compared to conventional silicon-based devices.
2Productivity
If higher switching frequencies are used to reduce charging time, then charging speed increases, but heat loss increases
Solution Approach 1:
The patent employs silicon carbide, a composite material with superior thermal and electrical properties compared to conventional silicon. SiC MOSFETs inherently exhibit lower on-resistance and higher thermal conductivity, which reduces heat generation during high-frequency switching operations. This material advancement allows the system to achieve high charging speeds while minimizing heat loss, resolving the contradiction between productivity and energy loss.
Solution Approach 2:
The patent converts the potential harm of high-frequency switching (which normally generates excessive heat) into a benefit by using SiC MOSFETs. These devices have such low on-resistance and high switching efficiency that the heat generated during high-frequency operation is minimal. The high switching frequency, which would normally be harmful due to heat, becomes beneficial for achieving fast charging with acceptable thermal management.
3Loss of time
If silicon carbide MOSFETs are used to reduce switching losses, then charging time decreases, but device complexity increases
Solution Approach 1:
The patent extracts the switching function from complex modular designs to a single integrated SiC MOSFET device. By using a monolithic SiC MOSFET module, the patent eliminates the need for multiple discrete components and complex interconnections required by silicon-based solutions. This extraction simplifies the overall device structure while maintaining the fast charging capability enabled by SiC technology.
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 SiC MOSFET module achieves faster charging than current silicon-based systems by minimizing switching losses and maintaining consistent on-resistance across temperatures, allowing for higher switching frequencies and compact circuit design, while providing users with the option to choose charging speed based on their needs.
Implementation Method 1
a heat sink that reduces heat loss from the SiC MOSFET module
Data Source
AI summary
An electric vehicle charging apparatus may include an external connector that is connected to an electric vehicle of a user, and a relay mesh that supplies electricity to the external connector. The amount of output power supplied through the relay mesh may vary according to the user's selection of fast charging or slow charging. The relay mesh may include a SiC module, and the SiC module may have a SiC MOSFET module serving as a switch for the electricity supplied to the external connector, and a SiC drive module sending a driving signal for switching to the SiC MOSFET module.