Scalar inverter for AC motors

I've to build a scalar inverter for an AC asyncronous motor <800W monophase or triphase for velocity and position control.
I dont' want to buy it and don't want to do a vectorial one.
Can someone help me with sample schematics, links or any ideas?

thx
Lollo

I know inverter. But ... what is 'scalar' inverter? What's the different from conventional inverter?

With term "scalar" i intend a regulation made by the simple voltage voltage / Frequency variation without regards motor model which is used in vectorial control to control the flux instead.
I haven't the power of calculation needed for vectorial control. So what I need is in few words a variable frequency/amplitude sine power generator.

Lollo

Well, you do not want vector or field-oriented controlled drive. Then, the following title should suit your application:

AC Induction Motor Control Using Constant V/Hz Principle and Space Vector PWM Technique with TMS320C240
**broken link removed**

Digital Signal Processing Solution for AC Induction Motor
**broken link removed**

Controlling 3-Phase AC Induction Motors Using the PIC18F4431
https://ww1.microchip.com/downloads/en/AppNotes/00900a.pdf

I have thinked a lot about this and i am intending to design one.
i found a lot of important things that u must know and we can co-operate about it:-
1-feed-back technique and its associated controller"PI,PID,...".
2-inverter output filter design.
3-v/f control necessitates a certain value which sould be known from the motor datasheet,and also must be controlled.
4-the "drive" interface,analog or digital!!.
5-the inverter pwm techinque used"SPWM,HEPWM,SAPWM,...etc".
6-single or 3-phase.
7-power rating and its extendablity.
8-the drive circuit analog,digital or micro-controller based
.....u can keep in touch with me on my e-mail
heavystriker@hotmail.com

Dear mostafa0020,
I'm interested in and I will contact you.
However my problem is to build a very basic inverter for single phase async motor.
The drive I think it is better and simple to use a microcontroller with its internal PWM generator(s).
Power max for my application is 1kW.
thx
lollo

U r welcome lollo,and that u said u need-like me- to build a prototype as i understood without,for ease,using MCU's,it is ok,i remember that in my qualification project,i managed to design and implement a symmetrical angle pwm driving circuit for an ac chopper with pll chip 4046 and a feedback frequency divider,with no microcontroller,that its programming may not be so easy. the results were impressive.
the matter of rating is no problem at all,it depends on the power circuit rating,while the drive circuit must have the capability of drivig such high power gate needs,which isn't a great deal,.
the time delay,for each two complementary switchs also must be taken in mind espeacially with high ratings,
i think the application note of microchip AN900 is very useful.
awaiting hearing from u
Mostafa

dear Mostafa,
I'm very interested in your design, but I haven't understood it very well. In particular: how do you generate the sine and v/f functions ?
I think it isn't easy without a microcontroller.
The power section is build with mosfet or igbt?

thx
Lollo

V/F control or constant flux IM control is mainly achecived using MCU's.I didn't decide it fully as this feature is a pure Motor driving need,leads us also to soft-starting.I didn't saerch this matter well , but, i think it is not so hard to do without a MCU.
The power section,i have used previously in my qualification project a MOSFET power switch, here ,MOSFET's are cheaper than the corresponding IGBT's for the same ratings.
I think both are good,but, MOSFET has higher switching frequency cabapility and a faster switching characteristics,but,higher conduction ON-resistance,Rds,
IGBT has a lower conduction ON-resistance,with a bit slower switching c/c's.

Dear Mostafa,
Can you share or send me in a PM your qualification design?
Which kind of mosfet you used?
thx
Lollo