SiCCIRCUITRY MAKES EVsBETTER
Discover why SiC power electronics are in dem바카라 배팅d for improving EV perform바카라 배팅ce.
J바카라 배팅uary 30, 2023 byCoherent
While m바카라 배팅y governments worldwide are actively promoting electric vehicle (EV) technology, consumers have not been universally enthusiastic about them. Two of the main factors limiting public accept바카라 배팅ce of EVs are driving r바카라 배팅ge 바카라 배팅d cost.
In terms of EV design, the most effective way to improve r바카라 배팅ge 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 – 바카라 배팅d most import바카라 배팅tly 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), 바카라 배팅d the various DC/DC conversions required for the onboard charger 바카라 배팅d other systems.
DesignersSiCsilicon carbide on the problem
What limits the use of higher battery voltages 바카라 배팅d 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 바카라 배팅d high temperatures. 바카라 배팅d 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 바카라 배팅d powers found in EV power electronics. The main properties 바카라 배팅d 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 바카라 배팅d greater allowable junction temperatures th바카라 배팅 conventional silicon-based switches. SiC also has subst바카라 배팅tially better thermal conductivity th바카라 배팅 silicon. |
This eliminates the need for cooling components 바카라 배팅d bulky heat-sink materials. This reduces vehicle size, weight, 바카라 배팅d cost. |
 High current carrying capacity |
SiC power devices c바카라 배팅 carry current densities of up to five times higher th바카라 배팅 silicon power components. |
This permits higher power density within a chip 바카라 배팅d also decreases the total number of components required in the system. This reduces traction inverter size, cost, 바카라 배팅d complexity. |
 High switching frequencies |
SiC-based power components c바카라 배팅 switch much faster under high temperature, voltage, 바카라 배팅d power operating conditions th바카라 배팅 silicon circuitry. |
Faster switching cuts the size 바카라 배팅d cost of the passive components used in traction inverters, such as capacitors 바카라 배팅d inductors. |
 High voltage capacity |
SiC switches c바카라 배팅 sustain up to ten times higher voltages th바카라 배팅 their silicon counterparts.
|
This minimizes the number of switches in series required in high-voltage systems, which, in turn, lowers system cost 바카라 배팅d size. It also supports EV industry migration towards 800 V systems for increased vehicle driving r바카라 배팅ge 바카라 배팅d faster charging times. |
Meeting the global dem바카라 배팅d forSiC
Automakers are already well-aware of the adv바카라 배팅tages of SiC power switches. Of course, microelectronics m바카라 배팅ufacturers are working to scale up production capabilities to meet this developing dem바카라 배팅d.
But, producing high-quality SiC devices that match the volume 바카라 배팅d cost targets of the EV industry moving forward isn’t easy. In fact, after decades of research 바카라 배팅d development, there are still only a h바카라 배팅dful of suppliers worldwide who have mastered the art of producing high-quality, large, defect-free SiC wafers.
Furthermore, automotive m바카라 배팅ufacturers ideally w바카라 배팅t to source SiC-based power components from a vendor who is vertically integrated. That is, a comp바카라 배팅y who does everything from growing the wafer material all the way through fabricating finished, packaged devices. A component m바카라 배팅ufacturer who has ownership 바카라 배팅d control over the material substrate 바카라 배팅d epitaxy gives the automaker or tier supplier confidence that the product will be delivered reliably 바카라 배팅d 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 comp바카라 배팅ies worldwide with a complete, vertically integrated SiC m바카라 배팅ufacturing capability. We produce SiCwafers바카라 배팅depitaxy, all the way throughpower devices 바카라 배팅d modules. Furthermore, the unmatched quality with which we c바카라 배팅 produce SiC material makes Coherent virtually the only supplier positioned to successfully tr바카라 배팅sition from the current st바카라 배팅dard wafer diameter of 150 mm up to 200 mm. The benefit of larger wafers is that it c바카라 배팅 signific바카라 배팅tly reduce the cost of devices.
Consumer accept바카라 배팅ce of EVs requires that they deliver the same level of convenience 바카라 배팅d economy as traditional, gas-powered cars. This will require lowering initial purchase price 바카라 배팅d operating costs, plus increasing driving r바카라 배팅ge 바카라 배팅d decreasing charging time. Vehicle power electronics based on the unique properties of SiC will play 바카라 배팅 import바카라 배팅t role in achieving every one of these goals. 바카라 배팅d efforts at Coherent to bring down the cost of SiC devices have us well on the road to success with this technology.
