This is an incredibly important advancement. It's nearly as important as the batteries themselves as the inverters, converters, etc weigh as much as the electric motor and can increase the efficiency of the system so you NEED LESS BATTERIES, it takes up much less space, and it requires much less cooling so that again reduces complexity, weight and space.

In this case, it also allows you to get rid of the old 12V battery in a component that was already going to be there for other conversions anyway. It's a win, win, win, win, win.

What's not to love. :)

It doesn't just need less cooling, it can use the engine coolant for cooling which in turn makes that heat available as cabin heat.  That isn't a huge amount at 1.3% losses, but every bit helps.

@Jeffgreen54, true, but the real measure is the curve of this one against the curve of of traditional silicon.

Every bit of reseach I've seen with SiC has shown the curve to be higher across the board.

Upconverters have been successfull in automotive applications for quite a few years. Toyota happens to use them in 650Vdc circuits using just silicon devices.

The introduction of an upconverter from 2004 onwards in the Toyota HSD powertrain for the Prius was undoubtably a game changer in HEV performance. For one thing it allowed the previous battery voltage to be lowered from 273v to 201v which permitted the use of fewer cells in the battery pack and a useful cost reduction. You have to bear in mind that the original 273V battery held only a miniscule 1.3Kwhrs of energy yet required 38 sets of battery modules each consisting of six 1.2v NiMH cells.

However the major advantage of an upconverter in this application was that it enabled the inverter system bus to run at 500 Vdc even when the generator MG1 was forced to rotate well below its max rpm which would have otherwise crippled the operation of the traction motor MG2. The circuit which employed a dual mosfet upconverter performed both the role of raising the 201Vdc battery pack to 500Vdc while at other times returning power back to the battery pack when circumstances allowed or when the battery was needed as a 10Kw power sink during regenerative braking.

As regards HEVs, in a climate which finds increasing numbers of roadside superchargers being installed, I see less and less need for an ICE in the vehicle to be necessary either. The HEV is a bridge technology whose time is running out for passenger cars and delivery vans. Except for transport trucks where it may become the niche market.

I also don't have any enthusiasm for the installation of supercaps and flywheels also mentioned above. All I see is a complication with a questionable cost justification.

In the situation of a pure BEV I just don't see the need for modulating the main bus voltage in this way.
High current devices with low V/Hz motors are the way to go. I certainly would not advocate the implementation of an artificial 750Vdc bus just to permit the use of lower current devices in the traction inverter.

If the goal is seriously to improve effcy then maxing out top speeds in the vicinity of 65mph should be the goal, that way punitive aero losses can be prevented.

It seems that funding for SiC semiconductors is being used here for studying different powertrain architectures. May I suggest one useful research direction which I believe deserves investigating specifically is the use of multiple traction motors:

Given TWO motors is it better to have each of them installed on the same axle for individual wheel drive or is it better to have each of them installed on different axles for AWD ?

At least Tesla, for one, seems to be taking that latter approach with AWD for its Model X slated for limited production in 2015.

My preference in powertrain improvement is any move towards the elimination of the open differential.

Anyone agree it's time we abandonned this rube device of the nineteenth century together with its unpredictable tendency to lose traction in adverse conditions. So there it is, I am viewing individual wheel drive on the rear axle as preferable with the additional opportunity to provide torque vector steering and traction control.

Perhaps a motorsport company should be taking a look at this.

David D:
The reason posts like this attract few comments usually is that they are above the heads of us non-engineers.
Personally I think engineers are socially useful, in spite of everything, and should at all times be treated kindly, locked in an internet equipped room and fed coffee and pizza are required.
On no account should they be allowed to speak, as that normally spoils it all.

'An engineer is a device for converting coffee into designs.'
:-0

That won't work without the pizza, any more than an anode without a cathode.

@T2,

Upping the voltage is important to reduce the size of the motor by running at higher rpm and in so doing, will reduce weight and cost. Copper and rare-earth magnet cost more than silicon used in the boost converter, and even more so for Si-C.

HEV's will remain very important long into the future. An HEV consumes far less battery capacity, less copper, magnet, and silicon than an equivalent BEV. A highly-efficient HEV can use synthetic fuel made from RE thus achieves independence from fossil fuel.

I share your idea regarding one motor per wheel hence eliminating the differential unit, while allowing vector control and assist with steering, traction and stability control, and lane control without requiring power steering servo. However, Henrik and Bernard did not agree with me on a previous discussion.

Davemart, LOL!!! Nice. As a former engineer who is now on the mgt side and one who has forgotten more than I now remember...I'll assume you're talking about E-P and not me

:)

Of course, I have two daughters in University as electrical engineers with both leaning towards power stuff (the older one is doing an intern at Oak Ridge National Lab this summer), I'm having to dig up the memory banks to keep up with them now. It's painful LOL

Yes DaveD....another good side of multi output ports DC-DC converters is the possibility to supply 12 VDC (to replace current lead battery) + 48 VDC for future more efficient lights and ancillaries with smaller cables + variable VDC to match selected drive e-motors. All from the main on-board battery pack.

Of course, smaller volume, less weight and increased resistance to higher temperatures are valuable side benefits.

Advancements in AC to DC, DC to AC and DC to DC converters will also help people with domestic RE power generation and storage systems.

Eventually, we may see a return to more efficient HVDC networks and lower voltage DC distribution systems to better satisfy our fast growing DC loads including future PHEV, BEV and FCEV DC battery charging.

Too bad that batteries and vehicle body & parts are not evolving as fast. Future, much lighter, stronger materials will probably play an important role in post 2020 vehicles. An under 2,000 lbs extended range BEV wmay become a reality by 2025 or so.

Harvey,
Yes, every little bit helps. It all adds up and keeps building and we'll hit a turning point.

I also should have said I disagree with T2 on one other item: I think supercaps could be a big winner combined with a battery system. Providing as little as 200Wh of supercaps that could handle acceleration and regen braking would allow the battery packs to be run at a nice, low C/2 or even less which increases their energy density and reduces wear and tear on the battery pack.
It does add some complexity, but I think that will be minor in the long run.

I'm with Jim McLaughlin on this one too...I'm just happy to see someone reporting on developments in this area.

Thanks GCC!

@T2,
Hmmm, no, I think you misunderstood where I was going with that. I agree with you wholeheartedly that pure BEVs are the way to go. Charging at home and only using fast chargers for the occasional "top off" is the way to go.

What I was alluding to is the energy density and cycle life curves for current lithium chemistry batteries. They all do better if you keep them at low C rates, preferably C/2 or even lower. You'll see batteries that are over 1,000mAh/g at c/4 and around 700mAh/g at C or C2.

So what i was saying is that until battery tech improves more, we could use Supercaps to do regen braking and then to accelerate again and take the high C rates off the main batteries. Otherwise, you have to have larger batteries to distribute the load.

It wouldn't take many supercaps as only about 200Wh can handle most accelerating and regen braking on light duty passenger vehicles. Slightly more complex in the electronics, but we're better at those than we are on batteries :)

But I'm totally with you on the "dark side"...it's BEVs for me all the way.