Porsche Patents New Way To Power Network Of DC Fast Chargers


First 350 kW DC CCS combo fast chargers at Porsche Berlin-Adlershof (source: Elektroauto im Alltag)

Porsche has been quite open about its efforts to offer drivers of its plug-in cars some ultra-fast charging in the coming years. The first of the company’s 350-kW DC CS Combo chargers went into operation last month and Porsche is working with other automakers to install thousands of these chargers across Europe in the next few years. But sometimes you need to look behind the scenes to confirm that

Which brings us to U.S. Patent application #20170240063. Filed February 8, 2017, and published today, the patent describes Porsche’s vision for “supplying a number of electric charging stations with electricity,” and high-power options at that. The idea is, “to optimize respective power factors of a number of charging stations for supplying a vehicle with electricity. … In order to minimize power losses, there is provision for the at least one transformer to comprise at least one delta winding and at least one star winding that are energized uniformly, so that a control phase offset and, as a result, a reduction in harmonics occurs, which increases the power factor of a charging station supplied with power in this manner.”

Of course, a 300-kW fast charge is well above the power that any EV on the market can handle today, but with this sort of forward planning, Porsche (and the other automakers involved in the push for the European network: Ford, BMW, Audi, and Daimler) is getting ready for the coming fleet of electric vehicles with massive batteries and short recharge times. The Mission E, for example, will reportedly be capable of recharging its ~95 kWh battery in about 15 minutes when it arrives in 2019. If you want to sell that, you’re gonna need a network of fast chargers ready and waiting. Just ask Tesla.

Source: USPTO

Categories: Porsche

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27 Comments on "Porsche Patents New Way To Power Network Of DC Fast Chargers"

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Even at lower power this is a thing, the Renault Zoe 3 phase has a terrible power factor at low loads. Grid operators don’t like that a lot, and you are billed for it too.

jim stack

P.F. Power factor is important to get a faster charge and not have a lot of waste heat. I have read and seen the Utilities don’t like it but you get billed by kWh’s not if it’s efficient or not.

n an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor.


Am I missing something here or is this Porsche patent in large part basically describing how Tesla has for a long while at Tesla Superchargers used multiple ac-to-dc inverters wired in parallel (the same Tesla made inverters used on-board Tesla cars)?


No, it seems to have not much to do with the AC/DC conversion at all. And parallel conversion is only really mentioned in claim 3 and there it indicates the converters are also switchable to series (voltage stacked). Tesla doesn’t use series (voltage stacked) DC outputs at all that I know of.


@unlucky said: ” Tesla doesn’t use series (voltage stacked) DC outputs at all that I know of.”

My understanding is that Tesla does use voltage stacked DC outputs for the DC Tesla Supercharger…each unit (charge pair) contains a stack of 12 [Model S] 10kW rectifiers for 120kW.


‘How it works’ – SuperCharger Station:


Those are “current-stacked” as the whole voltage range can be supplied by each converter. Porsche has to switch between 400 and 800V operation.


@vdiv said: “Those are “current-stacked” as the whole voltage range can be supplied by each converter…”

Sure seems to me looking at the Porsche patent image schematic
… and reading the Abstract:

“A method for supplying a number of electric charging stations with electricity, wherein AC voltage provided by an electricity source is transformed into a prescribed AC voltage level by at least one transformer via at least one star winding and at least one delta winding and subsequently routed via AC voltage lines to the number of electric charging stations and converted directly to direct current in respective charging stations from the number of electric charging stations locally by at least two rectifiers of the charging stations.”

That the setup is basically same as Tesla Supercharger.


Your link doesn’t work and you don’t say which diagram you mean.

I assure you that Tesla’s AC/DC converters are parallel. They are not isolated, they share a common reference (ground) and thus work together to provide the needed current. Each provides the full voltage.

Porsche proposes a system where the chargers are isolated and thus can reconfigure to provide either the more current or more voltage. This is surely so they can run their 800V-1000V system off regular 440V-ish power.

This is not the same as Tesla’s superchargers.


@unlucky said:
“Your link doesn’t work and you don’t say which diagram you mean.”

Here it is – link


That’s a link to the first page. You mean the first diagram?

That diagram doesn’t show how the output of the chargers are connected to each other. It doesn’t show if they are parallel (like Tesla) or series.

Go to that link and click the “full pages” button on the left and then look at page two, figure 2 on sheet 2 of 6.

It shows the outputs of the AC/DC converters being connected either in series (close the middle horizontal switch) or parallel (close the two vertical switches). Tesla doesn’t reconfigure theirs in this way to connect them in series, theirs are always in parallel.

Also note the diagrams all show the delta/wye secondary windings connected to the inputs of the AC/DC converters. I don’t know if Tesla uses that technique, do you?


Lighting in a bottle!
Almost No wait “lightning strike speed” Super-Duper insta-charging!


What in this is patentable, i.e. not done before? I can’t see how using delta and wye power and rectifying is a patentable idea.


It’s an application. Patentability in the US has not been determined yet. Publication of an application is not patenting.


what about the other manufacturers? Would be nice to make it a real standard.

Mike I.

This patent seems like a solution looking for a problem. Why not design your charger modules with unity power factor so you don’t have to compensate for it in the transformer? Tesla does not have this problem.


I suspect that you have found the right point. It could be a way to build chargers cheaper if you don’t have to worry so much about designing for unity power factor.


SPMS (switch-mode power supplies) inherently won’t a power factor of 1 unless they have power factor correction (PFC). And PFC adds costs.

Bill Howland

While this is a six-phase charging method and Tesla typically uses 3-phase charging methods – the scheme, at least from what has been stated here, isn’t patentable.

(Unless there is such a Snow-Job of the patent office that the gov’t doesn’t know what it is looking at).

Such schemes have powered electric trains and trolley cars ever since decently sized Mercury-Arc rectifiers were developed around 100 years ago.

If its high-efficiency they want, they can do that without any new patents.


Where does it say 6-phase?? It says delta, which is 3-phase.

It says 6-pulse, not 6-phase. It’s not really 6-phase. A 6-pulse rectifier is the 3-phase equivalent of what you call in single phase a full-wave rectifier. With 6 phases and 6 diodes you really do get 6 positive going pulses per cycle. With 6 pulses the minimum voltage from the composite DC waveform is 86% of the peak. This is very high and reduces the amount of smoothing capacitance you need to put in. I’d be surprised if Tesla didn’t use a 6-pulse rectifier also. The key in all this appears to be item 20. ‘[0020] Use of the at least one transformer, provided, with at least one star and/or delta winding each allows, in contrast to a three phase transformer that is usually used, active power factor correction to be dispensed with. As an alternative to active power factor correction by means of an output stage, the presented method provides for the use of two 6-pulse rectifiers per charging station that convert AC voltage transformed by the transformer into direct current locally for the respective charging station.’ I’m not good enough with 3-phase to understand why. But if tapping from both a delta and a wye from the same… Read more »
john Doe

Just look to Apple for many questionable patents, and . . I think this actually brings something to the market. Not just round edges, and slide to unlock..

Bill Howland

You guys don’t understand this stuff. – Doesn’t matter what it says. It is a 12 pulse per cycle method (6 phase).. Its been used for 100 years. Tesla’s system is 2 pulse in north american homes, and 6 pulse at the vast majority of their superchargers.

This is a 12 pulse per cycle method, to reiterate, used for 100 years already. Not much to see here, and less to patent.

Bill Howland

To repeat myself Unlucky: you don’t know what you are looking at. There are 12 rectifiers not 6 – the bottom schema is 60 degrees out of time with the top schema on a 360 degree basis. This makes it a SIX-PHASE , TWELVE-Pulse per cycle system.

Calling ‘delta’ 3-phase in isolation is an irrelevancy.

Bill Howland

Other facts that are true regardless of whether they were mentioned in the Patent application:

Ripple in s a 6 pulse system is 4%. This system is an IMPROVEMENT on 4% since there are 12 pulses per cycle rather than only 6.

Six-phase power apparently is BRAND NEW to others here. In fact it was used to drive the most efficient Synchronous-Converters back in the ORIGINAL IRC subway system in New York City even before the developement of large metal mercury arc rectifiers. It was used since 16% of the power flowed Straight Through the rotory coverter changing directly from AC to DC without any conversion at all. That is why the machine was so small for its size. That was around 115 years ago.

The concept here is almost as old as electricity usage itself, therefore it shouldn’t really be patentable – but VW is probably big enough to pull enough strings to get this “NEWLY DISCOVERED” method undeserved legal protection.

The ripple frequency at the DC output from the rectifier bank (top and bottom schema combined) is 600 HZ in Europe, and 720 HZ in North America.

Bill Howland
I’m glad that Porsche is thinking about efficient charging of their cars. To show how old this concept is, perhaps examining the original IRT (Inter-borough Rapid Transit) Powerhouse, built in 1904 (that’s 113 years ago) would be instructive. The building had multiple coal-fired boilers feeding small reciprocating vertical steam engines (to save space – even though the entire building was a full city block) driving direct drive 44 pole, 25 Hz Alternators running at 68.2 Revolutions per minute. The output was 11 kv 3 phase, to be sent via underground cable to 6 distant DC substations to prop up the 600 volts nominal the entire system required. No large transformers were at the Powerhouse since the output from each alternator was just combined with the others through switching and sent directly out under the streets. At the subway stations multiple 1500 kw Synchronous converters ran on 450 volt 6-phase 25 hz power from a serving 1500 kva 3 phase, 11 kv input transformer – 1 per machine. These efficiently provided the nominal 600 volts DC required by the trains. The output went through typically English Electric brand (some as large as 10,000 amperes) circuit breakers to feeders to the tracks… Read more »
jim stack

PFC Power Factor Correction is more efficient and keeps the heat down too. With high power charging heat can also be a problem. Tesla and others have used a cooled power cable to keep things cooler. It can’t be good for the batteries.
I don’t see why people want super fast charging. the Tesla Super Chargers at 100-150 kW seem very fast and hardly allow time to eat and stretch before you can continue the trip. It;s not good to sit for long periods. Read the book sitting kills. https://www.amazon.com/Sitting-Kills-Moving-Heals-Everyday/dp/1610350189


Apparently Tesla stopped using the cooled cables very quickly after they were noted as being deployed. No idea why.

It is expected that 350kW systems will have cooled cables. So someone will have to deploy it and keep it out there if that’s going to happen.