New Semiconductor Could Improve Vehicle Fuel Economy By 10 Percent 119
cartechboy writes: "Automakers are scrambling to increase vehicle fuel economy every year as regulations increase, so when an automaker finds a way to possibly increase fuel economy by 10 percent with one new part, that gets some attention. Today that automaker is Toyota, and the part is a new semiconductor. Toyota's power control units (PCU) in its hybrids use semiconductors to govern the flow of electricity between the battery and the electric motor. Unfortunately, they're also an electrically restrictive component. Toyota says the PCU accounts for a quarter of the total electrical power losses in a hybrid drive system, and semiconductors alone make up a full fifth of the total. Reduce electrical losses through a semiconductor, and you can make your hybrid system (and therefore your car) more efficient. Toyota has done this, in theory at least, using a new silicon carbide material for its semiconductors, rather than a standard silicon unit. The future could be shaped by individual parts, and this new semiconductor tech is one piece of that puzzle."
Old News (Score:2, Informative)
How is this news? SiC semiconductors including Schottky diodes, JFETs and MOSFETs have been commercially available since 2008. My first design to use SiC JFETs and diodes was in solar power inverter developed back in 2009 (and yes the RDSon and revers recovery times are indeed exceptional). Stay tuned for: "Toyota discovers wonder metal by adding carbon to iron"
Re:A better power MOSFET switch: Big deal. (Score:4, Informative)
It has a faster recovery time too. More MOSFET's won't change that.
Faster recovery time means they can run at a higher frequency and use smaller inductors to convert the voltage. Lower inductance means less copper, less resistance. So not only is there less loss in the transistor, there is less loss in other components.
If you keep adding more MOSFET's, you need to keep increasing the drive current or they'll switch slower.
While a MOSFET is switching, the resistance can be quite high. Even if faster silicon carbide transistors had the same Rds, there would be lower losses during switching.
Found a better site (Score:4, Informative)
Seriously, holy grail for current steering.
Can't find the vendor of the raw SiC so no idea about Delta-V / Delta-I limits but looks very good
10% net reduction in loss.