dclink, and universal converter to use

crying_baby

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Join Date
Mar 2005
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earth
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hi i m back


i learnt a lot from the thread i statrted and sory as almost entirely stubborn .
appologies for my rudeness n misunderstandings esp to steve bailey,jesper, tom n many many others. also for making most of u end up drinkin beer at the end

personally, i admit that i still have a lot room to improve at.

reading back the whole thread makes me realize.
after searchig in the laboatory, i found some of the drives can help me is the dc link and a universal converter.

with , i can drive the motor using external dc supply, and obtain 3phase ac rotating field. after reading the manual of the universal converter, i realize the converter communicates to another part of the circuiit thru a ribbon cable.

would it posible for me to use my ICU693UL006 to realise a model to control the motor?

i discusses it wif my prof. and he said it possible be done by using logic ;
000 stop motor
001 start motor
010 reverse motor
011 lowers/faster rtation
and so on

by sending proper signals to controlling the igbt's in the universal converter.

pls advise.
if it is possible to implement it .

attached is the universal converter that i r going to use wif me . its on LEFT MIDDLE of the page where it accepts dc in and 3phase ac out.

the problem reduces to how it is possible to send signal from plc discretely to command it.

such as 000=stop, etc.

i think i need to use 3output plm is that an alternative. or otherwise, plz help
 
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Crying Baby.

Do you have such a "universal converter" as the one in the diagram ?
It looks like some kind of laboratory equipment (essentially a VFD).
It is impossible to see in the diagram how the device is supposed to be controlled.
It could be that there is some kind of control electronics built into the device, and that this handles the timing of the IGBTs. If so, you PLC can probably control the VFD by simple start, stop, forward, reverse commands.
If on the other hand you are supposed to control the IGBTs directly, then your PLC cannot be used for that purpose.
 
Do you have such a "universal converter" as the one in the diagram ?
It looks like some kind of laboratory equipment (essentially a VFD).
It is impossible to see in the diagram how the device is supposed to be controlled.
It could be that there is some kind of control electronics built into the device, and that this handles the timing of the IGBTs. If so, you PLC can probably control the VFD by simple start, stop, forward, reverse commands.
If on the other hand you are supposed to control the IGBTs directly, then your PLC cannot be used for that purpose.

yes. the lab equipment is exactly look the same with the 1 in the diagram, even the wiring all r labelled similar as it shown in the picture. the vfd is a separable unit . the picture shows teh complete equipments in the lab for vector control the only 1 i m concerned is the vfd drive.

i try take some snap shots but my fren's camera is only 2MPi hope it helps. i upload it asap.

the problem is how to make my plc to communicate with it. my plc only has 1 output., do i reli has to resort to a multiple output (ie. 3 outputs at least) as the plc unit i meantioned availlable in the lab only .
 
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From your description, it sounds like you have a VFD in your lab. The only difference between what you have and what you might purchase from a supplier of drives is that the one in your lab is a big box of parts that have to be interconnected to turn them into a VFD.

Your first task is to study the subject of AC Variable Frequency Drives (VFDs) to learn enough about how they work. Next, study the documentation on the components you have avaialable to you to find out how they should be wired together. In that documentation you shoul learn about what control signals need to be applied to the system to make the motor start in either direction and how to change the speed. Armed with that knowledge, you compare the required control signals to the types of signals you can generate from the PLC.

You have a lot of reading ahead of you.
 
From your description, it sounds like you have a VFD in your lab. The only difference between what you have and what you might purchase from a supplier of drives is that the one in your lab is a big box of parts that have to be interconnected to turn them into a VFD.
Your first task is to study the subject of AC Variable Frequency Drives (VFDs) to learn enough about how they work. Next, study the documentation on the components you have avaialable to you to find out how they should be wired together. In that documentation you shoul learn about what control signals need to be applied to the system to make the motor start in either direction and how to change the speed. Armed with that knowledge, you compare the required control signals to the types of signals you can generate from the PLC.
You have a lot of reading ahead of you.


thank you steve,

the vfd is readily to be used when the LEFT side dc is applied and the RIGHT side gives 3phase ac.

the bottom part, is somehow, complicates it to recive signal from external parts alien to the set.
 
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The last diagram you posted didnt help much.
There must be some manual that explains in detail how the IGBTs are connected, how the 25 pin plug (number 7 in the diagram) is connected, and how the whole thing is supposed to work.
 
The last diagram you posted didnt help much.
There must be some manual that explains in detail how the IGBTs are connected, how the 25 pin plug (number 7 in the diagram) is connected, and how the whole thing is supposed to work.

thanks jesper,
i understand what to do now.
 
I know for a FACT that the PLC you specified has more than one output. It has ONE solid-state output, capable of a low frequency pulse-train, or simple switching. It also has 11 relay contact outputs.

/sigh.

Anyway, Here's my advice. Completely FORGET ABOUT THE PLC for now. If what you showed, is actually a Variable Frequency DRIVE, then your first step is just to figure out how to make a motor spin.

Do that.

Use switches for start/stop, forward/reverse. Use a potentiometer for a speed reference source.

Connect those simple, discrete devices to your drive, and see if you can make it work. If you can achieve that, then it is a very simple matter to connect those switches to the PLC INPUTS, and just plain mimic them on the PLC OUTPUTS. For the speed reference, you can use a frequency to voltage converter on the PTO output, or even a simple R-2R network on a group of ganged relay outputs.
 
I know for a FACT that the PLC you specified has more than one output. It has ONE solid-state output, capable of a low frequency pulse-train, or simple switching. It also has 11 relay contact outputs.

/sigh.

Anyway, Here's my advice. Completely FORGET ABOUT THE PLC for now. If what you showed, is actually a Variable Frequency DRIVE, then your first step is just to figure out how to make a motor spin.

Do that.

Use switches for start/stop, forward/reverse. Use a potentiometer for a speed reference source.

Connect those simple, discrete devices to your drive, and see if you can make it work. If you can achieve that, then it is a very simple matter to connect those switches to the PLC INPUTS, and just plain mimic them on the PLC OUTPUTS. For the speed reference, you can use a frequency to voltage converter on the PTO output, or even a simple R-2R network on a group of ganged relay outputs.

ok rdrash

i'll do study first. sry for the careless -.-"
 
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the manuals r brief. it had 0 examples for external control of the IGBTs

yes, the universal converter do support manual control of the transistors,

i will run the motor this sunday, using the ribbon and the converter i/0.
however, the lab assistant promised to run it using the ribbon , not the external control i/o




the converter's i/o which is another piece of equipment as attached, could provide RIBBON / EXTERNAL control ph1/1,PH1/2,PH2/1,PH2/2, PH3/1, PH3/2 which in other words, signals of the 6 power igbt transistors of the universal converter.

it uses bridging plugs,

additional control s INH : switches all power transistors to high ohmic,
CHOP1: control signal of the chopper transistor
CLR: ctrl signal of the main relay

logic is active low.


---------added info;
the actual inverter with 6IGBTs, fast acting inverting diodes, gate drives and protective logic circuitry, as been integrated into so-called "intelligent power module"

limiting data of the bridge, MAX collecter EMITER voltage U_CES=600v
max collector current, I_C=15A

typical switching times,
t_on=0.6microseconds
t_off= 2.0microseconds

max pwm frequency, 20khz

forward char IGBT and diode, saturation voltage for I_c= 30A
U_CE(sat)= typical 1.8v(max 2.5v)
threshold voltage for diode, with IC=15A
-U_CE=typical 2.5V(max 3.5V)

when we have a peak value of the collector current of I_C=30A, the mathemathecal result in the case of a sinusoidal current is max rms value of 21A. Due to the super imposed current harmonics and the limited current of the feeding 1phase mains 16A, the maxx continuous olutput current must be restricted to 8A

----------------------------------
pleaase advise,
 
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Crying Baby,
the photo that you attached has made me understand what you have to work with.
It appears to be complete laboratory equipment for learning and experimenting with VFD control of AC motors, complete with control electronics, DC-link, VFD prower stage, AC motor to be driven by the VFD, AC motor to represent a load on the driving motor, instrumentation etc. etc.

I cannot make it out from the picture, but obviously there is a control unit that connects to the IGBTs.

We cannot give you instructions how to connect or control this system.
You have to look into general textbooks about AC motors and VFDs, and the documentation for the lab unit. There must be a complete and comprehensive documentation for this unit. If you cannot locate it, then get a new set from the manufacturer.

(there is something really worrying about this thread, but I am too polite to spell it out openly).
 
the photo that you attached has made me understand what you have to work with.
It appears to be complete laboratory equipment for learning and experimenting with VFD control of AC motors, complete with control electronics, DC-link, VFD prower stage, AC motor to be driven by the VFD, AC motor to represent a load on the driving motor, instrumentation etc. etc.

I cannot make it out from the picture, but obviously there is a control unit that connects to the IGBTs - like you are allready to talk about.

We cannot give you instructions how to connect or control this system.
You have to look into general textbooks about AC motors and VFDs, and the documentation for the lab unit. There must be a complete and comprehensive documentation for this unit. If you cannot locate it, then get a new set from the manufacturer.

okie dokie. but i will need your expertise in this field. can i asks for advices when i get stuck in somewhere in teh lab..i.e. connection of the PLC to the control i/o n stuff not explained int eh manual
 
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I know for a FACT that the PLC you specified has more than one output. It has ONE solid-state output, capable of a low frequency pulse-train, or simple switching. It also has 11 relay contact outputs.

/sigh.

Anyway, Here's my advice. Completely FORGET ABOUT THE PLC for now. If what you showed, is actually a Variable Frequency DRIVE, then your first step is just to figure out how to make a motor spin.

Do that.

Use switches for start/stop, forward/reverse. Use a potentiometer for a speed reference source.

Connect those simple, discrete devices to your drive, and see if you can make it work. If you can achieve that, then it is a very simple matter to connect those switches to the PLC INPUTS, and just plain mimic them on the PLC OUTPUTS. For the speed reference, you can use a frequency to voltage converter on the PTO output, or even a simple R-2R network on a group of ganged relay outputs.

rdrast,

could you explain me the various ways to do the external connection of the pwm solid state output as well as the relays, of the PLC module. i read the manual all it state is connect the pwm to exteral resistor, is this what physically done







the photo that you attached has made me understand what you have to work with.
It appears to be complete laboratory equipment for learning and experimenting with VFD control of AC motors, complete with control electronics, DC-link, VFD prower stage, AC motor to be driven by the VFD, AC motor to represent a load on the driving motor, instrumentation etc. etc.

I cannot make it out from the picture, but obviously there is a control unit that connects to the IGBTs.

We cannot give you instructions how to connect or control this system.
You have to look into general textbooks about AC motors and VFDs, and the documentation for the lab unit. There must be a complete and comprehensive documentation for this unit. If you cannot locate it, then get a new set from the manufacturer.


jesper, thanks,

i will not be working with the entire equipment, only the converter control i/o and the universal converter aka vfd. the control i/o need external control signals into the unit. i reli nid some guides n your expertise, on this part as i had never done any such in depth practicals on PLCs and how, this can be realized using PLC as input,

plz enlighten me.
 
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