Help in 3 phase motor driver 1

[gaber26111]

Hi engineers and colleuges here,
Well, i am working on project related electric bikes, in other words i am working on the driving part,and i am alittle bit confused about some stuff.

We already specified a 380 acv , 7.5kw, 10 hp driver motor.
Also decided to use battery bank from chloride manufacturer, there are different values of rated volts and amps, i am thinking of 12v, 200ah battery, and use 3 or 4 of them in parallel or series depend on the design requirements of volts and amps. The power needed.

I am planning to use inverter between the battery bank and the motor,

Other way of design, to use 12dcv to 220acv inverter with the battery bank and then use 220acv to 380acv VFD to drive the motor with the suitable power needed.

What i need help and advise about is, is it possible to use inverter from battery bank to the motor?, in a direct way?, if so please suggest
Regards

 

[davidbeach]

I'm going to guess that going from 12VDC to 380VAC will be vastly more efficient and certainly far lighter than going from to 12VDC to 220VAC to 540VDC to 380VAC.

Somehow, though, I'm thinking that 12VDC and 380VAC may not have been the most compatible choices of voltages.

 

[ScottyUK]

Put your batteries in series to get the highest DC voltage possible. This will keep current down, allowing use of cheaper and lighter switching components, and will make more efficient use of the stored energy. DC-DC converter to get to about 600V DC, then find an off-the-shelf drive which can accept a raw DC input.

 

[itsmoked]

Read up on everything you can about Zero Motorcycles. They started in my town so I've heard about them. I actually walk my dog thru their parking facility once in a while. LOL

[URL unfurl="true"]https://www.zeromotorcycles.com/[/url]

They've done it really well. They don't waste the weight or the energy shifting voltages.

Here's some specs I stumbled over. I know at one time they were or were contemplating selling drive-train kits.

My understanding is that their battery packs are da'bomb and that a lot of their sales are their power pack technology.
http://www.zeromotorcycles.com/powertrains/powertrains-sales-sheets.pdf]powertrains-sales-sheets.pdf[/url]

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jraef]

Yes, forget the 12V to 220V inverter to feed a VFD, total waste. That inverter uses what's called a "boost converter" front end, and you can just have one made to take your 12VDC up to 600VDC to feed into your VFD. For a 380V motor, the DC bus needs to be at least 545VDC, so taking it a little higher to 600VDC allows you to run at full capacity for a little longer. The VFD will only put out the correct motor voltage necessary for the speed, but cannot itself "boost" voltage beyond what is fed into it. So as your batteries discharge and voltage begins to drop, having started out higher gives you a tad more head room.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[gaber26111]

Ok. Thanks all

The battery i am planning to use is 12v 200ah, ok. Good idea to use dc-dc conveter and raise the voltage to 600 dcv, then to 380acv to drive the motor.

One more question i am worrying about, the battery ampere won't be too much to operate the dc-dc converter?, in other words not too much for electronic components?

 

[davidbeach]

It won't be a problem if you pick a converter with the necessary capacity. Will be though if you don't.

 

[Compositepro]

You should not have to convert 600 vdc to 380 vac. The VFD has a front end to convert 380 vac to 600 vdc to charge the capacitors in its dc bus. Select a VFD that allows you to connect directly to its dc bus.

 

[gaber26111]

Compositepro , thanks for your opinion and help, can you send me link from aliexpress or alibaba for vfd with the specifications you talking about?

All the VFD i saw were to be feeded by 220acv, can yoi show me any source for dc input?

David beach. Thanks

 

[BrianPetersen]

https://www.youtube.com/watch?v=8Sw7rMdt8NI

 

[BrianPetersen]

Don't do any DC voltage conversion shenanigans. Arrange for your battery pack to be in a compatible voltage range to the DC bus voltage and do NOT do any DC voltage conversion. If your battery voltage isn't high enough, you need a different battery. If your motor required voltage doesn't match the VFD output at that DC voltage, you need a different motor.

 

[gaber26111]

Brian, the moto we have is ac motor, and the power source is batteries, so we must do the convert from dc to ac voltage.

 

[davidbeach]

That motor wasn’t the best choice to go with those batteries. You might be better off making different choices.

 

[BrianPetersen]

I know that. Hence the VFD.

A VFD is a device for converting DC into variable frequency and voltage AC. It so happens that they generally produce that DC by rectifying AC to begin with ... but you don't have to use that. You can access the DC bus directly, bypassing the rectifier. See the video that I linked to.

So DO that. It will require selecting the correct battery pack (with much higher voltage than the one you have). It will require selecting the correct motor that will work with the VFD of choice (which might not be the one you have).

You have to select the components correctly so that they match and will work together. That might not be the bits and pieces that you have on hand.

Bear in mind that electric vehicles also include many safety-related parts to minimize the chances of killing people or setting things on fire. High voltage DC is not a plaything.

 

[waross]

The motor wants Amp turns. It doesn't care where it gets them.
Many 380 Volt motors are star connected and can be reconnected in delta for 220 Volt use. The phase windings will see the same current and voltage and the same Amp Turns.
Due to the delta connection the line current will be higher, but the windings will see the lessor current.
So the motor may be suitable for use at 220 Volts,
The next thing to consider is reconnecting the coil groups.
Each phase winding is often built with a series of coil groups generally connected in series.
It may be possible to split the coil groups and reconnect in series parallel for motor use at 110 Volts or 73 Volts.
A motor shop may be able to verify whether this is possible with your motor.
You want the DC voltage to be about 1.414 times the needed AC voltage.
I suggest that you aim first for the highest possible battery voltage and then investigate the possibility of converting your motor to run on 0.707 of the DC voltage.
Two things to aim for:
1. Thee highest possible DC voltage.
2. Reconnecting or rewinding the motor to match the available battery voltage.
Feed the Dc onto the DC bus of the VFD.
The DC bus may be a connection point or terminal rather than an actual recognizable bus bar.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[gaber26111]

hello all ,

i decided to use 220 acv motor, instead of that 380v, as i rethought about it and discovered that it will be very danger for such a project, if happen any mistake during operation or for the maintenance technician while maintaining or repairing the bike

and it can be straightforward issue, battery then inverter then t the motor

the problem now that can i find 220v motor for 10 hp power?