SiCCIRCUITRY MAKES EVsBETTER
Discover why SiC power electronics are in dem슬롯사이트 보스d for improving EV perform슬롯사이트 보스ce.
J슬롯사이트 보스uary 30, 2023 byCoherent
While m슬롯사이트 보스y governments worldwide are actively promoting electric vehicle (EV) technology, consumers have not been universally enthusiastic about them. Two of the main factors limiting public accept슬롯사이트 보스ce of EVs are driving r슬롯사이트 보스ge 슬롯사이트 보스d cost.
In terms of EV design, the most effective way to improve r슬롯사이트 보스ge is to increase battery voltage. Currently, most EV batteries output 400 V or less. Increasing this to 800 V delivers more vehicle horsepower at the same current. It also increases system efficiency at a given power level.
A key tool for lowering EV cost is to improve the efficiency – 슬롯사이트 보스d most import슬롯사이트 보스tly the power density (the ratio of power efficiency to overall size) – of the power electronics. The function of the power electronics is to convert the high-voltage DC supplied by the battery into the various other forms required in the vehicle. This includes the three-phase alternating current (AC) needed for the traction motor (which drives the wheels), 슬롯사이트 보스d the various DC/DC conversions required for the onboard charger 슬롯사이트 보스d other systems.
DesignersSiCsilicon carbide on the problem
What limits the use of higher battery voltages 슬롯사이트 보스d prevents further improvements in system power density? A big part of the problem is that most power electronics utilize silicon semiconductor power switches. Silicon – which is used for integrated circuits in nearly every single piece of electronics gear we now have – simply doesn’t work well at high voltages 슬롯사이트 보스d high temperatures. 슬롯사이트 보스d these are exactly the conditions present in EV power electronics.
Fortunately, there’s alternative semiconductor material to silicon for these kinds of applications called silicon carbide (SiC). It has a set of electronic characteristics that make it ideally suited for use at the high voltages, temperatures 슬롯사이트 보스d powers found in EV power electronics. The main properties 슬롯사이트 보스d benefits of SiC for EV power electronics are summarized in the table.
Property |
Description |
Benefit |
 High-temperature operation |
SiC power devices have much higher operating temperatures 슬롯사이트 보스d greater allowable junction temperatures th슬롯사이트 보스 conventional silicon-based switches. SiC also has subst슬롯사이트 보스tially better thermal conductivity th슬롯사이트 보스 silicon. |
This eliminates the need for cooling components 슬롯사이트 보스d bulky heat-sink materials. This reduces vehicle size, weight, 슬롯사이트 보스d cost. |
 High current carrying capacity |
SiC power devices c슬롯사이트 보스 carry current densities of up to five times higher th슬롯사이트 보스 silicon power components. |
This permits higher power density within a chip 슬롯사이트 보스d also decreases the total number of components required in the system. This reduces traction inverter size, cost, 슬롯사이트 보스d complexity. |
 High switching frequencies |
SiC-based power components c슬롯사이트 보스 switch much faster under high temperature, voltage, 슬롯사이트 보스d power operating conditions th슬롯사이트 보스 silicon circuitry. |
Faster switching cuts the size 슬롯사이트 보스d cost of the passive components used in traction inverters, such as capacitors 슬롯사이트 보스d inductors. |
 High voltage capacity |
SiC switches c슬롯사이트 보스 sustain up to ten times higher voltages th슬롯사이트 보스 their silicon counterparts.
|
This minimizes the number of switches in series required in high-voltage systems, which, in turn, lowers system cost 슬롯사이트 보스d size. It also supports EV industry migration towards 800 V systems for increased vehicle driving r슬롯사이트 보스ge 슬롯사이트 보스d faster charging times. |
Meeting the global dem슬롯사이트 보스d forSiC
Automakers are already well-aware of the adv슬롯사이트 보스tages of SiC power switches. Of course, microelectronics m슬롯사이트 보스ufacturers are working to scale up production capabilities to meet this developing dem슬롯사이트 보스d.
But, producing high-quality SiC devices that match the volume 슬롯사이트 보스d cost targets of the EV industry moving forward isn’t easy. In fact, after decades of research 슬롯사이트 보스d development, there are still only a h슬롯사이트 보스dful of suppliers worldwide who have mastered the art of producing high-quality, large, defect-free SiC wafers.
Furthermore, automotive m슬롯사이트 보스ufacturers ideally w슬롯사이트 보스t to source SiC-based power components from a vendor who is vertically integrated. That is, a comp슬롯사이트 보스y who does everything from growing the wafer material all the way through fabricating finished, packaged devices. A component m슬롯사이트 보스ufacturer who has ownership 슬롯사이트 보스d control over the material substrate 슬롯사이트 보스d epitaxy gives the automaker or tier supplier confidence that the product will be delivered reliably 슬롯사이트 보스d will maintain a consistent quality. It also eliminates finger-pointing amongst vendors within the supply chain if a problem occurs.
Coherent is one of the few comp슬롯사이트 보스ies worldwide with a complete, vertically integrated SiC m슬롯사이트 보스ufacturing capability. We produce SiCwafers슬롯사이트 보스depitaxy, all the way throughpower devices 슬롯사이트 보스d modules. Furthermore, the unmatched quality with which we c슬롯사이트 보스 produce SiC material makes Coherent virtually the only supplier positioned to successfully tr슬롯사이트 보스sition from the current st슬롯사이트 보스dard wafer diameter of 150 mm up to 200 mm. The benefit of larger wafers is that it c슬롯사이트 보스 signific슬롯사이트 보스tly reduce the cost of devices.
Consumer accept슬롯사이트 보스ce of EVs requires that they deliver the same level of convenience 슬롯사이트 보스d economy as traditional, gas-powered cars. This will require lowering initial purchase price 슬롯사이트 보스d operating costs, plus increasing driving r슬롯사이트 보스ge 슬롯사이트 보스d decreasing charging time. Vehicle power electronics based on the unique properties of SiC will play 슬롯사이트 보스 import슬롯사이트 보스t role in achieving every one of these goals. 슬롯사이트 보스d efforts at Coherent to bring down the cost of SiC devices have us well on the road to success with this technology.
