Kettering University Working On 24-kW On-Board Electric Car Charger

JUL 26 2015 BY MARK KANE 41

The Green Ring Means All Charged Up


Kettering University’s Advanced Power Electronics Lab has been working on power electronics for a couple of years.

One of the topics of team lead by Dr. Kevin Bai, associate professor of Electrical and Computer Engineering, is high power, efficient chargers.

After the L2 10 kW charger project with Magna E-Car, they are now developing a 24 kW charger (approximately 95 percent efficient) for a Turkish automotive company.

That’s even more than the Tesla Model S and a Nissan LEAF could replenish energy in one hour; if you have enough amps to feed the charger.

Kettering University’s will be three-phase, so it will be more suitable for European markets.

“Dr. Kevin Bai, associate professor of Electrical and Computer Engineering, and his team of researchers are working with Derindere Motorlu Araclar (DMA), a Turkish automotive company based in Istanbul that is focused on developing electric vehicle integration. The company is helping Turkey reach its goal of producing a 100 percent electric car with their original vehicle design, developed with advanced technology to help build the future electric vehicle industry.”

“The electric car market in Turkey has been growing thanks to the high cost of fossil fuels and conventional vehicle taxation structure. Bai is working with a team that includes one research engineer, one postdoctoral fellow and one graduate student. They’re working on a three-phase 380-volt, 24-kilowatt high-efficiency charger that they hope to have completed in the fall.”

Dr. Kevin Bai said:

“We are collaborating with DMA on development of a 24-kilowatt charger. This will allow a vehicle to finish charging much faster than the presently existing 3.3kW or 6.6kW on-board charger, which would significantly reduce charging time and acceptance of EVs to customers.”

“We will deliver the charger working prototype to DMA by October.”

Good to hear that electric mobility projects are carried out in Turkey too.

“The success of such collaboration will be a win-win scenario. On one hand, Kettering power electronics team will gain more automotive industrial experience out of this project. On the other hand, DMA is expected to own a high-efficiency charger with lower cost, which makes their EVs more competitive.”

Separately we found video of Dr. Kevin Bai speaking about “Next-Generation Power Electronics Technologies in Vehicle Electrification.”:

Categories: Charging


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41 Comments on "Kettering University Working On 24-kW On-Board Electric Car Charger"

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So far behind !!!

I have a Renault ZOE with a 43kw on board charger. I drive that car since 2013. It was developed 2010.

So I am at least 5 years ahead.

Cool, these french guys.

24kW and 95% are good numbers. This implies that 1.2kW is lost during the charge process.

But those are not the only numbers to look for, efficiency at 3kW and 6kW do matter at great deal.

For example if you use a single phase 230V 16A supply and the Kettering system still loses 1.2kW, that would be a bad.

Which brings us the Zoe 43kW charger. If you connected it to a single phase supply, not enough power made it to the battery.

I see no reason why the kettering system should lose 1200 watts. These things are scalable.

Both the Zoe and this take 380 volt (400 volt nominal these days) input 3-ph so there is no difference there.

Besides, batteries have no low ripple requirement so the extreme smoothing lost when going to single phase mains is not so much of a deterent since the battery will charge anyway.


If you are trying to make a point here, I missed it.

My point is that Kettering should ensure their efficiency stays high when the charger operates on a single phase and low amps. Something that the 43kW Zoe charger designers failed to do.

My point is I thought everyone watched the lecture, that future devices will allow 2% points efficiency improvement.

Unfortunately, low cost will be bringing up the rear, so to speak, since SiC and GaN devices are currently very expensive.

I admire your optimism. I’ll believe the claims only after the product is made and tested.

In case you care about the current state of things, you can read about the Zoe and efficiency at Look for section “Refinement of the charging system at low power”

Haha, 2% Improvement for a large price increase doesn’t require much optimism.

Renault claims 8%. While I’d love to take these companies at their word, in view of the PLUGLESS device missing its advertised ‘specs’ in real world testing of a Chevy Volt, I’m actually a bit jaundiced.

Efficiency does not suffer at low amperage for the Cameleon charger. It is cos phi which is lower, therefore it is less effective, not less efficient.

If you are talking about the real to
apparent power ratio, that is cos theta.

But specifically could you give the efficiency of the charger at high input, and low input, listing:

1). Phase(s)
2). Nominal system voltage
3). Current
for both conditions please.

Since most vehicles will charge at home, the limit is really determined by the size of the home service. At some point, you’re hauling around more charger than you can utilize at home, and then it’s a question of why use AC instead of DC for public quick charging.

AC chargers are cheaper.

@ItsNotAboutTheMoney The chargers are cheaper but the cost is now borne by each car indicidually… for public infrastructure, even if they are more expensive per unit, DC chargers allow to shar the cost across all vehicles… which makes more sense in the end.


ItsNotAboutTheMoney said:

“AC chargers are cheaper.”

So, ItsNotAboutTheMoney, are you saying it is about the money? 🙂

Actually, it’s not. For instance, if EV makers wanted to go cheap, they could just put in a DC motor and not have to bear the expense of an inverter. Modern EVs use AC motors and inverters because that’s a more efficient use of energy, and also because they can develop high torque/power across a wide band of motor speeds that way.

Likewise, you’ll want an onboard charger that can charge the batteries as fast as is safe. Putting in a cheap onboard charger, one that can’t charge the pack as fast as possible (within safety limits) would be “penny wise and pound foolish”.

Sure, you can point to one or more current EVs which have rather limited charging speed. But going forward, those models won’t be able to compete with newer, faster charging models.

More Knee-Slapping comedy hour from PuPu. “Putting in a cheap charger….that can’t put out as much as the battery can take…would be.. pound foolish.” Since Gm has stated their cars can regenerate 60 kw for 10 seconds, and the battery can be charged at a 14 kw rate forever, please explain how EVERY GM VEHICLE currently made has a 3.3 kw charger. You must be smarter than all of GM. The motor statement was also dumb and inaccurate. Ever travel in a high-speed elevator more than 20 years ago? They universally used DC motors. Rockefeller Center old elevators were 1400 feet/minute. And using the SAME MACHINE they had to accurately level the car with the landing within a very small fraction of an inch, so precision wasn’t a problem. Actually, as people got on and off the elevator, the machine was ON. It was constantly releveling ever so imperceivably while the steel hoisting ropes stretched or contracted with the change in loading. New elevators use AC due to the availability of cheap inverters. Inverters are very cheap now, and the inverter / cheap ac motor combo is overall lower cost. Plus there are no brushes to change, nor commutators to… Read more »

Bill Howland said:

“…please explain how EVERY GM VEHICLE currently made has a 3.3 kw charger. You must be smarter than all of GM.”

My comments were in the context of BEVs. You’re talking about PHEVs, and thus you’re taking my comments out of context.

Let’s see if GM sticks with a measly 3.3 kW charger for the Bolt. I’m betting they won’t.

Bill Howland also said:

“More Knee-Slapping comedy hour from PuPu.”

“The motor statement was also dumb and inaccurate.”

Well, Bill, I see how you’ve gotten a reputation here for being the most prominent of those who obstinately continue to argue no matter how obviously wrong you are.

While your info regarding DC motors in elevators is mildly interesting, it is entirely irrelevant to my point that every single modern highway-capable mass produced BEV is powered by an AC motor and inverter — not a DC motor — and that all these drivetrains can be traced back to Alan Cocconi’s invention of the integrated motor controller/inverter.

No one here, Bill, was trying to say that elevators are BEVs… or vice versa. 😉

Haha, there’s nothing more frustrating than listening to an idiot who thinks he knows everything. Last time I checked, they weren’t selling SparkEv’s with a gas engine.

The reason I mentioned elevators is obviously because it is a similar transportation problem, involving smooth acceleration, and regenerative braking, and also OverHauling which exists in electric cars but is not stated as such. (Cruise control set at a constant speed going down a hill – in most cars this can be effectively performed if the car has a heavy enough regeneration).

Motor control has been around far longer than electric cars (unless, you’d include the ones from a century ago), and the most surprising thing is that the auto industry is the LAST to use this technology, not the first.

GM’s claim to fame is in heavy use of early programable controllers to transfer work from hourly to salaried workers, since this was the main impetus.

Efficient variable speed, four-quadrant motor control existed far before GM started using it. Why? Because there was a transportation need for it, and it wasn’t cars.

I expect your ‘wikipedia response’ any minute.

So you’re unaware that, in most European countries, there is 3-phase, 240V (each phase), high current service to each breaker panel, home or office. Not to the curb, to the panel.

In other words, you’re hauling around exactly what you need to drink straight from the fire hose. Every hose. It’s a question of why you’re hauling around all your misinformation, Mart.

May be, but in some European countries I’m told the service is 40 amps 240Y/400, which would be difficult to service a 43 Kw Renault if anything else was being used in the house.

Most smaller North American homes also simply don’t have 43 kw available for a car, let alone 2 cars.

Britain also, generally doesn’t have polyphase sevice in smaller homes, and in North America, even some millionaires do not have polyphase service.

So while France may have this, its difficult to generalize.

I believe there is a N-A market for a semi-fast ~20-24kW DCFC, with a single phase 240Vac input to feed small business delivery car: restaurant, car parts, etc. Otherwise, this onboard AC 380/3/50, not much…

I would have love to have the same EU three phase AC input connector instead of N-A single phase connector.

Why not use the motor inverter to both charge and run the drive motor?
Using them bidirectional is an old common idea in UPS systems.
And you could charge as fast as motor power could take.
So 100kw inverter would be up to 100kw charger.
Of course limited to what the station can put out and batteries can take.

Renault Zoe does that. But there are some electrical issues because the system is not galvanic separated, which means some DC-current might flow back into the grid. Since we have an AC grid at the household level, there is nothing like a DC sensible protection or fuse. This has to be upgraded in every case where this special form of charging takes place (which is doable for about 300-600$).

>Why not use the motor inverter to both charge and run the drive motor?

If you substitute the word “motor” here for “battery pack” you are describing what Alan Cocconi of AC Propulsion developed many years ago.

Actually using the motor as a generator saves substantial weight and bulk as opposed to a stand-alone charger.

Why not? Because you’ll be sued by AC Propulsion.

Even the later Roadsters had to have new ‘transformered’ PEMs to stop Ac Propulsion squawking.

Tesla Motors got its start with EV tech by licensed AC Propulsion’s tech. What reason would AC Propulsion have to squawk? Did Tesla quit paying the licensing fee? If they did, surely it was because Tesla found a better way to do it… not because they didn’t want to pay for the license anymore.

Every single modern, highway-capable, mass produced EV owes its drivetrain to the integrated motor controller/inverter invented by Ian Cocconi, when he was at GM. That tech was developed into the drivetrain for prototypes which lead to the EV1. Cocconi went on to co-found AC Propulsion. So the origin of all modern EVs (other than some cheaply made low-speed NEVs) can be traced to Cocconi and his invention. However, perhaps some of Cocconi’s patents have run out by now — patents only last 20 years — so perhaps at least some of that can be used without paying GM or AC Propulsion licensing fees.

If this is tesla’s ‘better method’ then strangely (not really, I’m just humoring him) they don’t use this with the model S but does it the same way every other US manufacturer does, with a separate charger, when the easiest way would be to use the built in rectifier.

Isn’t it how the Renault ZOE so called Chameleon charger works?


From reading the comments here, and seeing some sketchy info, it appears the Renault device is the more elegant, yes.

This is really the wrong direction.

How about developing a good external and inexpensive DC FC unit (EVSE) and then removing the need for onboard AC-DC chargers at all?

Eventually, if enough DC FC external chargers are made available (to homeowners and to businesses) then the need for every single EV having a somewhat expensive on-board charger can be removed and lower the costs of EVs to buyers.

On the flip side, requiring all public charge points to have a DC charger present will only increase the cost of installation, discouraging more public EVSEs. Most people already balk at the premium for public charging (in my case, home ~ $0.14/kWh, public ~$0.49/kWh). Businesses are struggling to build a business case for installing these things, since most charging is at home. They can never compete with home charging prices.

This is part of why I think that high-powered onboard chargers, combined with less expensive AC EVSEs, could potentially lead to a more robust charging infrastructure.

Don’t know if you saw the email, but a friend’s current bill from NG with NG as the supplier yielded 10 1/3 cents/ kwh marginal cost, taxes and fees included. In Amherst, NY. Cheap.

I’m betting your friend doesn’t opt to pay extra on his bill to support wind power. Also, the difference between 10 1/3 cents and 49 cents is even greater, further supporting my point.

Oh ok wasn’t aware of that: I was just trying to make a plain jane comparison of what my bill would be with and without solar panels.

I looked up the info on MicroChp in NYS.

10 kw residential net metering.
1000 kw bio-fuel farm. Farmers also get a discount from their delivery charges.
1500 kw fuel cell.

For Solar it is 25 kw residential and 50 kw commercial, unless you get a special deal, which must be happening all over the place because the Kohl stores by me have 260 kw systems.

There is also a ‘remote’ net meter, wherein you can have a Canadian – Style system that just makes solar power, and use it to reduce your electric bill at a totally different commercial establishment.

Before I read that I wondered what the sense of a solar powered ‘driveway’ was , which was generating 100x the power used by the streetlight. I now see this is just decreasing the firm’s electric bill at some other totally distant building.

Its a bit of a horse race, apparently. The Lecture was stating current Refrigerator sized devices will be replaced (without the intermediate DC link – more of a Cycloconverter topology – he didn’ say that but I’m saying that), with higher efficiency suitcasse sized devices that people will carry with them, eliminating the need for ANY charger and just having a recepticle at the side of the road.

The horse race of course, is whether the price of SiC and GaN devices can fall fast enough to make this transpire before too many of the ‘old fashioned’ (current) units are installed.

Bonaire said:

“How about developing a good external and inexpensive DC FC unit (EVSE) and then removing the need for onboard AC-DC chargers at all?”

It does seem strange to me that EVs need both. If the onboard charger is capable of converting AC to DC, as is needed for slow chargers like the EV owner’s home charger, then why do they need an external EVSE? The answer, of course, is lack of standardization in wiring and plugs.

Sure, and then we’ll tell criminals to just follow the laws from now on. Prisons have high-voltage service; we can restripe the prison yards into parking spaces!

Unfortunately, the reality of the economics in the U.S. make this infeasible.

First, you would have to be willing to have a car that cannot charge from AC at all. No J1772’s. No UMC’s with 110v plug ins. Otherwise, you’d be carrying a rectifier around anyways. It makes sense to size that rectifier for 100% charging in 6-8 hours at a minimum. That way, a vehicle can charge off of a J1772 overnight to full.

Then, consider the expense of DC charging… a 24 kW DC CCS charger is $6,500, not installed. A 19.2kW Tesla HPWC is $750. A 50 kW dual standard CHAdeMO/CCS EVSE is likely around $50,000 installed and requires 480v, 3 phase input supply.

It makes sense that the medium term future – out 10-15 years, we will have to have a dual standard for charging in the U.S.. J1772’s up to 80A which fits nicely with existing electricity supply and installed equipment and is enough to charge even 150 kWh battery packs overnight, as well as DCFC > 200 amps to support long distance travel.

Of course, the $750 thing, like my $735 thing years ago (80 and 30 amps, respectively), being EVSE’s, dont do anything.

If you watched the lecture, a 1500 watt charger brick could be made at least as small as the current ones. Going from 150 deg centigrade devices to 400 would bring in the 5 fold reduction in size as the professor stated. And since the control electronics need not take up much space, it seems very do-able to me, if you care to pay for the devices. 2% higher efficiency would reduce the already low waste.

As far as the VOltecs that come with GM products, those things are so physically huge that CURRENT 1500 watt supplies for other industries already are no bigger. A 5 fold reduction in size to make a 1500 watt dc charger a reality just makes the size problem easier. The last thing that might be big is a power line frequency capacitor, but as mentioned, there is no low-ripple smoothing requirement when it comes to charging batteries.

have an elec motor werks level 2 charger
able to deliver 15 kwh however on board is 6.6 oh well such is life my charger looks like it belongs on the BIG BANG THEORY
very hi tech and cool looking CODA CAR STILL STRONG JUST PAST 15,000 miles 1 yr 3 mnths old

My Alma Mater, but I never worked in an Advanced Power Electronics Lab. It would be fun to be back there working on these types of projects.