7kW charger for automotive use (230VAC mains three phase input)?

[treez]

Thankyou, here is corrected 3 phase rectifier as per your correction.
I believe PF of 0.96 not sufficient with such high power level?

Not only that, but how do you do an active pfc for such a bizarre current shape? (ie the current wave shape that one gets with a resistive load at the output of a 3 phase rectifier)

 

[Orson Cart]

Above 16A per phase PFC is not mandatory....

 

[FvM]

The tread is inconsistent in this regard, but most posts suggest a 230/400 V supply. If so, we have about 10 A phase current with 7 kW and IEC 1010-3-2 power quality requirements apply.

 

[treez]

Above 16A per phase PFC is not mandatory....

Thanks, do you know, you confirm my suspicion there......but I think this will change when car chargers get very popular, because there will be millions of them in each country, and PFC will surely be brought in for 16A plus car chargers......this would have to happen...I mean , if you've got PFC for 75W Plus, and everybody has a 16A charger, then they just have to bring in PFC for 16A plus.

Also, thanks to FvM (we posted simultaneously), I believe all car chargers of whatever power will be slammed with a 0.99 plus PFC requirement.

 

[Warpspeed]

I am not sure if these requirements actually fully apply world wide at this stage.
But any company serious about export needs to at least be aware of the harshest international standards, even when they may not yet apply in equipment in country of origin.

 

[treez]

yes, for any company to start making non-PFC'd car chargers for the mass market, this would be suicidal...even if they complied with current regulations......it is obvious, that if car chargers become a mass market item, they will all, regardless of power level, become liable to requirements for PFC of 0.99+

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I believe we agree that the three phase rectifier will not be used for car chargers since it can't be used with PFC. But if it were used, which one would it be, the one with star input (580V output), or delta input (330V output)?

LTspice simulation attached of these types

..incidentally you can see that with a resistive load, the delta input one has better pfc.

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Anyway, I believe we have agreement.......because its more than 10 amps, it will be a three phase input.....and because these will be very common, we will need full PFC in each phase.....that cuts the solution space right down.

What we are left with is two interleaved CCM PFC stages per phase ([7/3] KW) , feeding two interleaved phase shift full bridge converters which are output current regulated......they will each be programmed to supply a third of the total charging current, because there are the three phases.

 

[treez]

**broken link removed**

do you know how the above web page offers a 32A , 7KW charger for "domestic" use?....I mean, no domestic house has three phase supply, and 3 phase is needed for anything above 13A?
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**broken link removed**

..Also, why does this 7kw charger (just above) weigh 60kg?...is it because it contains all the 50Hz iron based magnetics as kindly discussed by Dan Mills?

 

[Warpspeed]

Many domestic premises in Australia have all three phase, particularly if the load is high. My own home has all three phases, and its excellent for motors and rectifiers.

If I was building a 7Kw battery charger (for myself) I would just use a honking great iron cored three phase transformer and a six pulse phase controlled SCR rectifier.

But a modern professional electronics design for a large scale commercial project is an entirely different thing to how I would build a simple one off for myself at home.

 

[Mr.Cool]

even for yourself in your own home, you might appreciate PFC

sunny, your post is the correct one. especially for a job interview Q&A

 

[Warpspeed]

even for yourself in your own home, you might appreciate PFC

Why ?
We are only charged for true resistive in phase watts.

 

[Orson Cart]

@FvM does IEC 1010-3-2 apply to 3 phase equipment with no neutral? I assume there is no requirement in the USA, and I know there isn't in NZ or Australia.

 

[FvM]

does IEC 1010-3-2 apply to 3 phase equipment with no neutral?

There's no reservation in the standard.

Previously. PFC is rarely applied in the field of industrial power conversion, except for a few large systems where the input power rating matters. So nearly all AC/DC and AC/AC converters are using simple three-phase bridges. Despite of IEC 1010-3-2, this also the case for < 16 A/phase input current. Power utility companies are just disinterested.

Electromobility is a new field which might enforce different practice. If you design a mobile vehicle charger, you should be at least prepared for PFC requirements.

 

[Mr.Cool]

Why ?
We are only charged for true resistive in phase watts.

agreed with that, and also energy is cheap at 10c/kWh
but there is also power factor is so bad due to such high harmonics that it starts to mess with your laptop, TV, playstation etc. PFC can help with this by making the current less harmonic and more sinusoidal so other things connected to your local household network are no influenced too much

 

[Dan Mills]

At least in the UK there is no problem getting more then 16A single phase, there is no standard domestic connector for the purpose, but there are sane industrial plug options for 16,32, 63 & 125A single phase that can be used.

Most domestic supplies are 100A single phase (Usually no domestic aircon load over here), and 32A for a charger is not going to be a big deal.

Regards, Dan.