Induction machine parameters?

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seyyah

Joined: 07 Oct 2001
Posts: 578
Helped: 1

31 Oct 2004 20:38 induction machine parameters

How can we obtain or estimate the induction machine parameters of Rotor Resistance(Rr), Mutual Inductance(Lm), and Rotor Self Inductance(Ll'r)?

Especially using a dsp or ucontroller without applying external tests like locked rotor test etc. I mean a controller board will estimate the parameters like in professional motor drivers.

Also a brief information on locked rotor and no-load tests would be nice.

nicleo

Joined: 06 Sep 2004
Posts: 717
Helped: 60

02 Nov 2004 4:03 low speed rotor induction machine calculations

I just did a Google search using these keywords "induction motor parameter estimation". The search returned many useful links. Probably you wish to try first.

seyyah

Joined: 07 Oct 2001
Posts: 578
Helped: 1

02 Nov 2004 6:44 how to measure induction motor parameter

Yes, bu it is returns thousands of links. It has a lot of methods and a lot of sources.
Some of them are useful, some of them are not. Some of them are practical some of them are not. Sometimes it takes too much time to find a useful thing and i get tired of searching. And also you can't find everything through google and if you're a beginner on the subject you can't decide easily which one(method) is better. I asked here, because an experienced people who have studied on the subject or made the search or a research about this can help much more than a google search.

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02 Nov 2004 6:44 Ads

nicleo

Joined: 06 Sep 2004
Posts: 717
Helped: 60

02 Nov 2004 8:10 speed calculation of induction machines

seyyah wrote:

Yes, bu it is returns thousands of links. It has a lot of methods and a lot of sources.
Some of them are useful, some of them are not. Some of them are practical some of them are not.

You get the points. Therefore, sometimes it's not easy to give comment if a question is too general. Smile

Probably you should share (little bit on) your application. For example, is it for sensorless (positionless, encoderless) speed control? Cheer ...

seyyah

Joined: 07 Oct 2001
Posts: 578
Helped: 1

02 Nov 2004 19:41 indirect foc induction motor

Yes you're right. So i'm giving some more information. I mentioned about the needed paramaters. The machine will be drived by a voltage source inverter. It will be an indirect vector control. A dsp will be used. I will sense the stator currents and i'm planning to make speed control. I don't think a sensorless control at the beginning. May be later i can add it. So a speed encoder will be attached to the motor. Do you know any good practical techniques or resources about this subject. (papers etc.)

nicleo

Joined: 06 Sep 2004
Posts: 717
Helped: 60

03 Nov 2004 4:14 vectorial control machine induction

seyyah wrote:

Scalar Control vs Vector Control
Vector Control ≡ Field Oriented Control (FOC)
Vector Control » Direct and Indirect
Induction Motor + Vector Control « - » Control of DC motor

I think the following link might help:

Using the dsPIC30F for Vector Control of an ACIM
http://ww1.microchip.com/downloads/en/AppNotes/00908a.pdf

Last edited by nicleo on 04 Nov 2004 1:32; edited 4 times in total

seyyah

Joined: 07 Oct 2001
Posts: 578
Helped: 1

03 Nov 2004 5:02 induction machine parameters without testing

The links itself have no useful information but may be the references may have. i don't have an access to the IEEE. May be

[8] M.A. Ouhrouche, Design of an Induction Motor
Speed Controller Robust Against Rotor Resistance
Variations, Proceedings of the IASTED-MS’99 International
Conference. Philadelphia, Pennsylvania,
USA, 1999, pp. 445-449.

and this

[12] S. Wade, M.W. Dunnigan and B.W. Williams,
Modeling and simulation of Induction Machine
Vector Control With Rotor Resistance Identification,
IEEE Transactions on Power Electronics, Vol. 121,
No.3, 1997, 495-506.

have some info. Do you know anyway to reach these documents?

nicleo

Joined: 06 Sep 2004
Posts: 717
Helped: 60

03 Nov 2004 6:54 important motor parameters vector control

seyyah wrote:

Yes you're right. So i'm giving some more information. I mentioned about the needed paramaters. The machine will be drived by a voltage source inverter. It will be an indirect vector control.

Techniques to obtain those parameters are dependent on the control strategy, application, etc. As you're working on 'indirect vector control' of IM, we at least know where to start now. Smile

seyyah wrote:

And also you can't find everything through google and if you're a beginner on the subject you can't decide easily which one(method) is better.

Probably my assumption that you're a beginner in this topic is not correct since the beginning. My apologize... Smile

seyyah wrote:

The links itself have no useful information but may be the references may have.

"The links itself have no useful information"... really? Sad

I thought the first one was helpful, as it shows you how to implement vector controller in DSP (practical, as you asked for).

seyyah wrote:

[12] S. Wade, M.W. Dunnigan and B.W. Williams,
Modeling and simulation of Induction Machine
Vector Control With Rotor Resistance Identification,
IEEE Transactions on Power Electronics, Vol. 121,
No.3, 1997, 495-506.

***Only [12] was found in IEEE Xplore. Pls find reference [12] in the attachment.

My understandings on Direct Vector Field Control (DVFC) and Indirect Vector Field Control (IVFC) are as follows:

1) DVFC - the position/angle of the rotor flux space vector is obtained by direct airgap flux measurement (e.g. using search coil or Hall-effect devices)

2) IVFC - the position/angle of the rotor flux space vector is obtained analytically (e.g. from slip-speed)

For very low-speed operations and for position type control, DVFC strategy is not good as the integrator associated with the search coil has a tendency to drift at low speed. IVFC strategy, which does not rely on the measurement of the airgap flux,
does not have such problem. According to literature review, IVFC is much more easier to be implemented than DFOC. However, the slip-speed calculation requires motor parameters (e.g. rotor resistance and magnetizing inductance, and hence rotor time-constant), which are known to be varied and dependent on frequency and temperature. For accurate control using IVFC strategy, on-line parameter adaptive techniques are often employed to tune the value of these parameters used in IVFC controller to ensure proper operation. After Google Search, I think the following two papers should provide you some info on parameters identification of induction motor:

(for seyyah 3) Deleted ... think it's for beginner only
(for seyyah 4) Deleted ... think it's for beginner only
(for seyyah 5) Implementation of a DSP Based Real-Time Estimator of Induction Motors Rotor Time Constant

Sorry, but you need login in to view this attachment

Last edited by nicleo on 04 Nov 2004 1:46; edited 2 times in total

seyyah

Joined: 07 Oct 2001
Posts: 578
Helped: 1

03 Nov 2004 20:31 identification of induction machine parameters

I said that they are not useful because they give the basic principle. I think that i passed that step. I can do something if i know the parameters. The second step will be the parameter identification and may be the compensation. Because i can't know every motor's parameters. I appreciate your efforts. I'll look at the documents which you've sent ASAP. Thanks.

seyyah

Joined: 07 Oct 2001
Posts: 578
Helped: 1

03 Nov 2004 20:47 acim foc control

Quote:

My understandings on Direct Vector Field Control (DVFC) and Indirect Vector Field Control (IVFC) are as follows:

1) DVFC - the position/angle of the rotor flux space vector is obtained by direct airgap flux measurement (e.g. using search coil or Hall-effect devices)

2) IVFC - the position/angle of the rotor flux space vector is obtained analytically (e.g. from slip-speed)

For very low-speed operations and for position type control, DVFC strategy is not good as the integrator associated with the search coil has a tendency to drift at low speed. IVFC strategy, which does not rely on the measurement of the airgap flux,
does not have such problem. According to literature review, IVFC is much more easier to be implemented than DFOC. However, the slip-speed calculation requires motor parameters (e.g. rotor resistance and magnetizing inductance, and hence rotor time-constant), which are known to be varied and dependent on frequency and temperature. For accurate control using IVFC strategy, on-line parameter adaptive techniques are often employed to tune the value of these parameters used in IVFC controller to ensure proper operation.

According to my knowledge, the difference between the two strategies is basically comes from the obtaining of unit vector sin(Teta_e), cos(Teta_e). In DVC, unit vector is obtained from the flux model. It's not important to measure or estimate it. There are two estimation methods basically. One of them is voltage model estimation which is better in high speeds and current model estimation which is better at low speeds. So in a wide range speed control a hybrid model can be used.
In IVC, unit vector is obtained from the integration of the sum of slip speed and rotor electrical speed. Again you can measure or estimate them. As you said, IVC is easier to implement and used widely. But it has a drawback of parameter identification and compensation especially rotor resistance may have important effect.

bunalmis

Joined: 03 Jan 2003
Posts: 254
Helped: 5
Location: Turkey

03 Jul 2009 22:16 induction motor parameters

I am looking FOC principles. All books discuss this method on the star connected motor.

Can we use FOC for delta connected motor? Why all books interest by star connected motor?