# 600 V controller for 3 phase asynchronous motors



## mr2 (Oct 12, 2009)

Hi

I am searching for a special kind of controller for 3 phase motors.
The difference between my request and normal BLDC-controller is that I do not need the PWM and sensing.

I have tried to google a hex-program that do not have the PWM included, but all is using PWM to regulate the speed of motors.

The only variable I need is the frequency that the circuit will operate on.

So if I program the microprosessor that the motor will go at 50 hz, the switching is done accordingly a BLDC, but without PWM and any sensing from motor.

Is there anyone that can help me with this?


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## steven4601 (Nov 11, 2010)

Hi MR2, Welcome to the forum.
What car are you going to convert?

I think I know what you want to do... May I take a guess?
You want to drive an AC motor with a fixed 50Hz frequency out of a square wave voltage?


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## mr2 (Oct 12, 2009)

steven4601 said:


> Hi MR2, Welcome to the forum.
> What car are you going to convert?
> 
> I think I know what you want to do... May I take a guess?
> You want to drive an AC motor with a fixed 50Hz frequency out of a square wave voltage?


The car is not yet decided. I have to first find out if it works on 3 phase motors first. It's a new invention I have. 
On 1 phase not so good motors I have achieved 59 % decrease of energy needed to do the same amount of work. 

Now I need to do a test on 3 phase high voltage asynchronous motors to see if it works there too.

But all BLDC controllers with its ATMEGA controller uses PWM to regulate speed. I am using just the frequency of cycles.

I am making a perfect sinusiodal drive of the motor without EMF.
But PWM destroys the effect.


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## steven4601 (Nov 11, 2010)

OK, you have a budget for the donor & conversion? Designing & building your own motor drive/ inverter soon ads up, possibly even more expensive.


Driving AC induction motors as traction drives requires control of the rotor current. This can today only be done by a concept named Field Oriented Control. This is a fancy word for rotor slip control. 

I do not think the stator & rotor would work together very well with square voltages. The current is likely very difficult to get sinus sodial at low rpm's. At Max power point & up where the torque would start to roll off as the maximum applied voltage is being applied may work with square waves. But I cannot imagen it to work for lower RPM's without PRM.

Since when did PWM go out of fashion? 
What is your background? Have you studied the common existing 3 phase ac drive principles?


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## mr2 (Oct 12, 2009)

steven4601 said:


> OK, you have a budget for the donor & conversion? Designing & building your own motor drive/ inverter soon ads up, possibly even more expensive.
> 
> 
> Driving AC induction motors as traction drives requires control of the rotor current. This can today only be done by a concept named Field Oriented Control. This is a fancy word for rotor slip control.
> ...


 The motor will ”see” a clean AC made without PWM. But not normal 3 phase, but like a BLDC driven motor. I know the motor will not notice any difference from normal PWM. There is no square voltages. Just perfect sinus.

I have only tried my invention on normal BLDC motors. Thats because I haven’t yet been able to find a program without PWM. I could use money on professionals, but if there is a easy way to remove the lines enabling PWM would be the best way. Then I will find out how effective my invention is.


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## steven4601 (Nov 11, 2010)

Quite mystical. 

You are not referring to resonant switched mode supplies/drives are you?
What college/uni background do you have?


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## mr2 (Oct 12, 2009)

steven4601 said:


> Quite mystical.
> 
> You are not referring to resonant switched mode supplies/drives are you?
> What college/uni background do you have?


Nothing like that. Just a new way of using energy.

I have no background. No education in this. But I am tested at Mensa, using 10 minutes to answer the 45 questions and when deliver the formular, asking them if they couldn't do better.. Max score 145.
Envying Sheldon Coopers eidetic memory.. hehe..


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## peggus (Feb 18, 2008)

mr2 said:


> I have only tried my invention on normal BLDC motors. Thats because I haven’t yet been able to find a program without PWM. I could use money on professionals, but if there is a easy way to remove the lines enabling PWM would be the best way. Then I will find out how effective my invention is.


If you've been able to test your scheme on BLDC why can't you test it on induction motor? Both are 3ph machines, there is not much difference in the controls.


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## DavidDymaxion (Dec 1, 2008)

Well, you could run the switches in a linear mode to get perfect sine waves. However they'll get hot and will need to be grossly oversized. Full on (low resistance) and full off (very high resistance) are low heating states for silicon switches, but 1/2 gives resistance that heats them up.

You could also do a scheme with many batteries, and switch the voltage up and down via various combos of batteries. It's going to be a challenge to keep the batteries balanced, but at least you can have your voltage jumps as 2 or 3 Volt steps rather than 0 to full pack voltage.

A typical system has inductance and capacitance, this tends to smooth the PWM waves.

Something you might want to look at is switched reluctance. You just switch them coarsely, not the fine fast switching of typical PWM. The shape of the poles helps give you some sine-like behavior.


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## mr2 (Oct 12, 2009)

peggus said:


> If you've been able to test your scheme on BLDC why can't you test it on induction motor? Both are 3ph machines, there is not much difference in the controls.


No, the motor that has been tested is only 1 phase. http://www.torin-sifan.com/display.asp?product=131


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## mr2 (Oct 12, 2009)

DavidDymaxion said:


> Well, you could run the switches in a linear mode to get perfect sine waves. However they'll get hot and will need to be grossly oversized. Full on (low resistance) and full off (very high resistance) are low heating states for silicon switches, but 1/2 gives resistance that heats them up.
> 
> You could also do a scheme with many batteries, and switch the voltage up and down via various combos of batteries. It's going to be a challenge to keep the batteries balanced, but at least you can have your voltage jumps as 2 or 3 Volt steps rather than 0 to full pack voltage.
> 
> ...



It is not done in any of those ways. I have a power source, my invention, the switching and then the motor. Nothing more, nothing less. The perfect sine is selfachieved. Should not be there, but it sure happens. No spikes at all when switching on-off. No BEMF.

I am just looking for a hex-file for ATMEGA processor without PWM and any normal sensing (Hall or EMF) from typical 3 phase BLDC motors.


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## Qer (May 7, 2008)

mr2 said:


> But I am tested at Mensa, using 10 minutes to answer the 45 questions and when deliver the formular, asking them if they couldn't do better.. Max score 145.





mr2 said:


> No BEMF.


You know, even if you spiked the Mensa-test it doesn't give you the rights to break the laws of physics.


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## Salty9 (Jul 13, 2009)

Assembly programming is tedious but not really difficult.


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## mr2 (Oct 12, 2009)

Qer said:


> You know, even if you spiked the Mensa-test it doesn't give you the rights to break the laws of physics.


No, and I don't.

But it is not the question why and how it works or not, but if anyone know how or can help me out with a hex-file without PWM and trigging by sensing either by Hall or EMF.

Just the switching like BLDC 3 phase motors by a frequency set in a variable.


I made these lines in C

#include<avr/io.h>
#include<util/delay.h>

int main()
{
unsigned char i;
DDRA = 0xFF; // all a-ports as output

while(1)
{
for(i=0;i<6;i++)
{
PORTA=0; // open all outputs that gives break before make

// _delay_ms(1); (optional delay 1 ms before make)

switch(i){
 case 0:
 PORTA=162; // step 1
 break;
 case 1:
 PORTA=97; // step 2
 break;
 case 2:
 PORTA=145; // step 3
 break;
 case 3:
 PORTA=84; // step 4
 break;
 case 4:
 PORTA=140; // step 5
 break;
 case 5:
 PORTA=74; // step 6
 break;
}
_delay_ms(150); // length of pulse
}
}
return(1);
}



Would this work?


Maybe use 1 b port as input for sensing if the motor is running...


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## ElectriCar (Jun 15, 2008)

How's it coming Mr2? Been a few weeks now.


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## alexcrouse (Mar 16, 2009)

mr2 said:


> No, the motor that has been tested is only 1 phase. http://www.torin-sifan.com/display.asp?product=131




That's a DC motor....


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## ElectriCar (Jun 15, 2008)

Are saying single phase is DC? If so you're incorrect. 120V motors are single phase as are 208V and 480V motors that have only TWO WIRES. That's single phase. There also is no such thing as two phase. It's either single phase or three phase and of course there's DC.


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## alexcrouse (Mar 16, 2009)

ElectriCar said:


> Are saying single phase is DC? If so you're incorrect. 120V motors are single phase as are 208V and 480V motors that have only TWO WIRES. That's single phase. There also is no such thing as two phase. It's either single phase or three phase and of course there's DC.


That motor is listed on their website as DC, PWM control.


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## DavidDymaxion (Dec 1, 2008)

Actually there are 2 phase motors. The second phase is driven by a capacitor, causes a delay for that phase, just to get the motor started. Then it is primarily a single phase motor once running.

You wouldn't do a 2 phase motor in an EV because it would take 8 switches. Doing 3 phases takes just 6, because you can hook the field coils together in a star or delta arrangement. There might be some esoteric math thing with the phases, too, any comments on that Major?


ElectriCar said:


> Are saying single phase is DC? If so you're incorrect. 120V motors are single phase as are 208V and 480V motors that have only TWO WIRES. That's single phase. There also is no such thing as two phase. It's either single phase or three phase and of course there's DC.


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## alexcrouse (Mar 16, 2009)

DavidDymaxion said:


> Actually there are 2 phase motors. The second phase is driven by a capacitor, causes a delay for that phase, just to get the motor started. Then it is primarily a single phase motor once running.
> 
> You wouldn't do a 2 phase motor in an EV because it would take 8 switches. Doing 3 phases takes just 6, because you can hook the field coils together in a star or delta arrangement. There might be some esoteric math thing with the phases, too, any comments on that Major?


Correct.

To All:
But as i said, that motor is a 24v DC according to the manufacturer. I know more about motors than most people, and i am NOT saying that DC = Single Phase, just to clarify. That motor is DC, NOT Single Phase. At least that's what the maker says.


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## Dan Hawkins (Jan 3, 2010)

alexcrouse said:


> Correct.
> 
> To All:
> But as i said, that motor is a 24v DC according to the manufacturer. I know more about motors than most people, and i am NOT saying that DC = Single Phase, just to clarify. That motor is DC, NOT Single Phase. At least that's what the maker says.


Well Yah, but did the maker ace Mensa?


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## alexcrouse (Mar 16, 2009)

Dan Hawkins said:


> Well Yah, but did the maker ace Mensa?


Doubt it. But i got a 134. Not bad at all. 

Also, i can spell to save my life.


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## major (Apr 4, 2008)

DavidDymaxion said:


> Actually there are 2 phase motors. The second phase is driven by a capacitor, causes a delay for that phase, just to get the motor started. Then it is primarily a single phase motor once running.
> 
> You wouldn't do a 2 phase motor in an EV because it would take 8 switches. Doing 3 phases takes just 6, because you can hook the field coils together in a star or delta arrangement. There might be some esoteric math thing with the phases, too, any comments on that Major?


Hi Dav,

Yep, we used 2 phase machines in my power conversion labs in college. Had a 2 phase source. Same theory holds. Machines can be designed for practically any number of phases. 3 phase has the clear advantage, as you point out 

Regards,

major


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## ElectriCar (Jun 15, 2008)

Not to be argumentative but in a three phase system, a motor may have two of the three power legs connected to it but it is still considered single phase power unless all three phases are connected to it. 

In a 240V residential AC unit compressor for example it will have two legs of power connected to it but actually has three legs coming from the motor. The capacitor via phase shift creates an artificial third leg. I don't work with HVAC engineers and never had the need to know if that type motor was technically a three phase but it does have three windings so I'd assume it is, though it is universally known as a single phase compressor motor being it is in a single phase condensing unit.

In American homes you have two hot wires and a neutral/ground leg. If you tell an engineer it has two phase power he may laugh at you but he will know that you're talking about what is universally known in the industry as single phase power. If you look on the application for power for new construction, the form for the local power company will have the option for single phase or three phase, not two phase.


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## jeremyjs (Sep 22, 2010)

I thought 2 phase was basically what your standard 220v outlet is?

120v single phase Hot neutral and ground. 240v 2 phase 2 hot wires reading 220v between them, using each other as neutral, and 110v each to ground and 240 3 phase each reading 240 between any 2 of the legs and 120v to ground. with obvious variations. For example many large industrial connections running 480v 3 phase, 240v per leg to ground and 480 between the legs.

Not an electrician but this is what I've always seen.


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## ElectriCar (Jun 15, 2008)

Look at it this way. With 1 hot and a neutral connection, you can connect an O'scope to the two wires and you will see one sine wave or phase. Same thing with two hots. For three phase systems, you can connect three probes between the three phases and see three sine waves or "phases" that are 120 degrees apart. 

Here's a visual of a three phase generator and the three phase conbinations.

Here's a visual of a single phase generator and the "single" phase signal you get from it.

The point is the motor sees the applied power just as the scope displays it. There is either a connection and a voltage between two "single" points or three points creating three 120 degree phases.


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## major (Apr 4, 2008)

major said:


> Hi Dav,
> 
> Yep, we used 2 phase machines in my power conversion labs in college. Had a 2 phase source. Same theory holds.


Hey guys,

Here is a description of 2 phase. http://en.wikipedia.org/wiki/Two-phase_electric_power It shows the power I used in the lab, way back when. Also, says:


> Three-wire, 120/240 volt single phase power used in the United States and Canada is sometimes incorrectly called "two-phase". The proper term is _split phase_ or _3-wire single-phase_. The two live outputs of a 3-wire single phase transformer secondary winding are properly called "legs".


Regards,

major


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## ElectriCar (Jun 15, 2008)

Unfortunately major nowhere in this thread was anyone referring to that system so that is immaterial. It may exist but I've never seen it in industry, power systems or machinery and I've worked on a lot of equipment and power systems in my day.


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## major (Apr 4, 2008)

ElectriCar said:


> Unfortunately major nowhere in this thread was anyone referring to that system so that is immaterial. It may exist but I've never seen it in industry, power systems or machinery and I've worked on a lot of equipment and power systems in my day.


What about posts #17 & 19?



ElectriCar said:


> Are saying single phase is DC? If so you're incorrect. 120V motors are single phase as are 208V and 480V motors that have only TWO WIRES. That's single phase. *There also is no such thing as two phase.* It's either single phase or three phase and of course there's DC.





DavidDymaxion said:


> Actually there are 2 phase motors. The second phase is driven by a capacitor, causes a delay for that phase, just to get the motor started. Then it is primarily a single phase motor once running.
> 
> You wouldn't do a 2 phase motor in an EV because it would take 8 switches. Doing 3 phases takes just 6, because you can hook the field coils together in a star or delta arrangement. There might be some esoteric math thing with the phases, too, any comments on that Major?


edit: And the motors you sight here are not 3 phase, but 2 phase via the capacitor on the second winding, so you actually have seen them 



ElectriCar said:


> In a 240V residential AC unit compressor for example it will have two legs of power connected to it but actually has three legs coming from the motor. The capacitor via phase shift creates an artificial third leg. I don't work with HVAC engineers and never had the need to know if that type motor was technically a three phase but it does have three windings so I'd assume it is, though it is universally known as a single phase compressor motor being it is in a single phase condensing unit.


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## ElectriCar (Jun 15, 2008)

Dude what is it with you? That system has nothing to do with EV's, is not what the original topic of discussion was and thus is not pertinent to this thread. I made that comment as it was the truth as I knew it from experience and what I was taught. I'm on this board to help and get help when I need it. I don't get off on contradicting others for the sake of argument. I will argue my point if warranted and relevant and I think someone is going down the wrong road. 

But dude, WGAF if somewhere in a lab somewhere in the world there exists such a thing as two phase power??? It's pre WWI technology, so ancient that neither I nor my instructors in the 80's ever saw or heard of, never worked on it and it's not what I nor the people I responded to were talking about. It's not relevant.

You can call a three winding motor a two phase motor with a capacitor if you want. To me it's a three phase motor, it has three windings wired to three phases even if one is created via capacitor.


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## major (Apr 4, 2008)

ElectriCar said:


> Dude what is it with you?


You know? I may be one of the few, possibly the one on this board who has done a 600 V controller for 3 phase asynchronous motors for vehicle propulsion, and a number of them. I was following this thread and commented when David asked. Even though two phase power supplies are obsolete, it was taught at university because it enabled the fundamental understanding of polyphase theory. I'm sorry you don't appreciate history or my attempt at help. I'm sorry I posted on your thread. It won't happen again.

Regards,

major


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## aeroscott (Jan 5, 2008)

I'm with Magor ,when I run my single phase welder or water heater off 2 legs of my 208 v. 3 phase generator , it's 2 phase ( legs are out of phase by 120 d.)


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## rochesterricer (Jan 5, 2011)

Some of you need to develop a much thicker skin on the internet. Because we lack the guidance of facial expressions and tone of voice, it is very easy to misunderstand a person's intentions over text. Please try and give people the benefit of the doubt.


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