Hi all,
Currently I am working on to design the motor controller for a 3 phase Induction motor.Rating of the motor is 310V, 400A, 172Kw and input frequency 230Hz. It's a AC three phase motor supplied with a battery for automotive application. So first I have to design the three Phase invereter to convert the DC to AC supply and secondly I have to supply 230Hz input frequency for that I have to design VFD.
I have a douth, In the inverter design only VFD can be designed or the VFD should be designed separately whose input will be from the Inverter?

As I am new to the design of inverter and VFD please guide me through the process of designing the circuit for the same?

Thanks in advance..

 

You are virtually committed to design with a micro processor, Picmicro has application sheets on AC motor and VFD design.
http://www.microchip.com/design-centers/motor-control-and-drive/motor-types/acim
Max.

 

No inverter needed. Use a VFD and feed it DC.

 

No inverter needed. Use a VFD and feed it DC.

Does VFD also converts DC to AC. As the motor I am using is a 3 phase AC induction motor

 

Most VFD's have a large capacitor bank fed by a 3ph bridge rectifier on the supply input, this also allows the option of 1ph or 3ph supply.
As stated, if you already have the DC available use this direct.
Depends on the level of DC and the rating of the 3ph motor.
Max.

 

What automotive battery are you using for this 172kW load?

 

Hi all,
Currently I am working on to design the motor controller for a 3 phase Induction motor.Rating of the motor is 310V, 400A, 172Kw and input frequency 230Hz. It's a AC three phase motor supplied with a battery for automotive application. So first I have to design the three Phase invereter to convert the DC to AC supply and secondly I have to supply 230Hz input frequency for that I have to design VFD.
I have a douth, In the inverter design only VFD can be designed or the VFD should be designed separately whose input will be from the Inverter?

As I am new to the design of inverter and VFD please guide me through the process of designing the circuit for the same?

Thanks in advance..

No need to design anything. There are large VFD units that already handle such operation and more.

They are most commonly called 'Spindle Motor Drives' and are use in machining center systems.

Does VFD also converts DC to AC. As the motor I am using is a 3 phase AC induction motor

To be honest if you have to ask that question this whole concept is way over your head and well beyond your ability to ever build yourself.

For us who work with such systems you having to ask how a VFD works is like saying you want to build a nuclear power station then asking what radiation is.

 

No need to design anything. There are large VFD units that already handle such operation and more.

They are most commonly called 'Spindle Motor Drives' and are use in machining center systems.


To be honest if you have to ask that question this whole concept is way over your head and well beyond your ability to ever build yourself.

For us who work with such systems you having to ask how a VFD works is like saying you want to build a nuclear power station then asking what radiation is.

Thankyou sir for your reply.
what I know is that for VFD the input should be AC. for my application that is a EV, 3 phase AC induction motor is to be used whose input power will be from DC battery.
Can this DC from the battery can be given directly to the VFD or I have to invert it first to AC with the help of inverter.
Please correct me if I m wrong anywhere, Help me in understanding this .

Thankyou..

 

Virtually all VFD's immediately convert the incoming AC to DC via a 1ph/3ph rectifier, so initially you do need a DC supply, but is the level of DC sufficient for a 3ph motor drive?
Max.

 

Virtually all VFD's immediately convert the incoming AC to DC via a 1ph/3ph rectifier, so initially you do need a DC supply, but is the level of DC sufficient for a 3ph motor drive?
Max.

THank you sir for your reply,
Its a battery powered EV, where the power to the 3 phase Ac motor will be provided by the DC battery,as we cannot give DC power to the Ac motor we have to convert it to AC with the help of inverter and the AC power out of the inverter can be fed to the VFD for getting 233hz.

CAn VFD alone can do both the work of DC to Ac convertion and frequency control ?

 

I'm concerned for your safety and the safety of anyone around if you're having to ask these questions. A 172 kilowatt motor is not a toy, and failure to control it properly could be disastrous.

Can VFD alone can do both the work of DC to Ac convertion and frequency control ?

Yes, if designed right. Have you researched how VFDs work?
What battery will you use to drive this motor?
Is this a college project/assignment?

 

While holding bare copper in your bare hands.

Insert the conductors into the power socket.

Stand back and admire Darwin in all his extinction level event predictions.

Woo who. What did I win?

 

I'm concerned for your safety and the safety of anyone around if you're having to ask these questions. A 172 kilowatt motor is not a toy, and failure to control it properly could be disastrous.

Yes, if designed right. Have you researched how VFDs work?
What battery will you use to drive this motor?
Is this a college project/assignment?

Thankyou for your reply,
Yes this is a college project, where I have to suggest the whole system and try to simulate the same, I am struggling in deciding the workflow,plz help me in that.

 

Here is a pdf outline of a system using a VFD, DC bus and industrial induction motor.

 

VFD's of the size and power you require will not work with battery packs of lower voltage like 48, 72 or 96 volts.
You will need 500 to 600 volts DC to operate the VFD that motor needs.

 

Thankyou for your reply,
Yes this is a college project, where I have to suggest the whole system and try to simulate the same, I am struggling in deciding the workflow,plz help me in that.

Ok then you need to focus on the forest, not the trees.
Abandon all ideas about designing an inverter and designing a VFD.
These are silly notions, unnecessary. There is a myriad of products commercially available that meet your requirements.
If you are to design your own inverter and/or VFD, then you may as well design your own 215/70-15 tires to go onto it.

 

Since this is a college assignment you need to show us your best effort so far at a solution. We can give hints, but don't do the design for you.
Have you decided what is plausible in the way of battery supply, which are the critical parts etc you need help with?

 

You may get some insight as to what it entails from such as this: http://www.microchip.com/design-centers/motor-control-and-drive/motor-types/acim
Max.

 

In your case buying an off the shelf unit would be far more practical.

http://www.southlandautomation.com/vfd/f510-4250-c3-u

250 HP. ~$8700

Would need a ~575 - 725 volt DC power source though.