Detailed information on the working principle of a vector controlled drive, its response time, controlling techniques and accuracy are needed.

please reply me

 

There are different types of vector control, CV current vector, FAM field acceleration method, IFOC indirect field oriented control, to name a few.

Regardless of the type, the goal is to significantly improve the dynamic response, efficiency and overload behavior over varying load and speed conditions, compared to the simple V/Hz technique. An ideal motor benchmark is the well known dc brush motor with separately excited field.

The flux producing and torque producing circuits are decoupled and directly controllable i.e. field, armature current/voltage control. The
mechanical commutator ensures the electromagnetic vector angle is kept at 90 degrees for optimum torque producing conditions.

An induction motor with V/Hz control is incapable of achieving optimal torque conditions due to poor magnetizing current and slip/angle control.
Some of the limitations: poor efficiency over varying load conditions and speed range; linear torque control not possible; torque control at zero speed not possible; poor dynamic and overload response.

In general, vector control greatly improves induction motor performance by achieving control of the flux producing (magnetizing) current and
electromagnetic vector angle (slip). The above V/Hz limitations are eliminated.

If your interest is from a user/application point of view, don't need to know much more than this. If you give me your fax number, I can fax some
more details about vector control vs. V/Hz. Useful information also from the many suppliers of induction motor drives, as well as the industry magazines: IEEE, Control Engineering, Motion System Design etc.

If your interest is from a highly technical point of view, there are textbooks on the subject. Try the internet, amazon.com etc. with keywords:
vector control, adjustable frequency drives, electrical machines etc.

One tip: the textbooks I've looked at are very math intensive - explaining from a purely theoretical point of view. Tendency to over complicate the basic theory of vector control. Unfortunately, no textbooks seem middle ground i.e. bridging the gap between the drives researcher and practicing motor-drives/motion engineer.

 

If you have any additional information on vector controlled drives please fax at the following no.
My office fax no is 91-422-301515 Please address to B.Srinivasa Rajkumar electrical engineer

 

I would like to know more information about vector flux vs. V/Hz from a user point of view. Thank you.

 

Vector flux helps you to achieve constant load torque even at very low or very high r.p.m. of the motor which V/Hz drive will not be able to provide you. So if speed accuracy under varying load conditions is more important to you select vector drive else select V/Hz drive.

Pradeep Chatterjee
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