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        Micro Brushless ESC development

#1 billystiltner Nov 12, 2003 05:35 PM

Brushless ESC development
 
Hey
This is the Brushless ESC development thread.
Post all links and info that would be useful for developing a micro brushless esc.
This will keep from hijacking the micor brushless motor thread.

So far we have
This which uses a 16F877 and some mosfets plus other bits for the controller.
http://www.microchip.com/1000/suppdo...n857/index.htm

Recomended by Steve H(shoutchen)


I'll have to look up the
TC4469's to see what they are. They are supplied 12V
so should be replaced with something that can handle 3.6V or 7.2V for single or dual cell lipoly. also The mosfets should be able to be replaced.


Then Gail(GailInNM) reccomends one of the Cygnal 8051 clones.
http://www.cygnal.com/Products/C8051F300DK.htm
http://ee.cleversoul.com/8051.html

I'll have to skip messing with this unless I can find a DIY programmer and free compiler.


Billy

#2 shoutchen Nov 12, 2003 06:22 PM

tc4469
 
http://www.microchip.com/1010/pline/...4469/index.htm



they are basically just drivers to put between the pic and the highrt curretn mosfets....


Steve H

#3 billystiltner Nov 12, 2003 06:26 PM

So they could probably be excluded with a lower power motor and mosfets.

This is good less weight.

Billy

#4 clipclop Nov 13, 2003 06:30 AM

Billy,
have a look here.
http://www.radetzki.info/html/sbl_micro_e.html

#5 Allan Wright Nov 13, 2003 09:16 AM

interesting subject, but shouldn't it be in a different forum?

#6 billystiltner Nov 13, 2003 09:20 AM

Stewart
Thanks.

Alan
Nope.


Billy

#7 Graham Stabler Nov 13, 2003 09:49 AM

Now that I have changed the thread title this forum is fine.

#8 Dave Wulff Nov 13, 2003 09:49 AM

Allan,

Got to agree with Billy, I think the enthusiasium for developing both the micro brushless motor and controller will only come from within this forum. That said, the theory will come from elsewhere, Yahoo has a great outrunner brushless forum. I don't understand all the info yet, but I can't help but dream of the torque of a geared motor without the gears.

Dave

#9 billystiltner Nov 13, 2003 10:12 AM

Thanks Graham and Dave.

The controller can be used for 2 micro motors being developed /discussd in this forum, Mikes motor and Gordon and Grahams motor. I think Mike allready has a controller but probably would not be available to everyone without some hoop jumping. Gordon and Graham's motor can use existing controlers but could benifit with a lighter weight controller.


On another note the microchip controller has sesored and sensorless code so it can be programmed to work with either kind of motor. would be cool to have both in the pic and have a switch for changing modes.

Billy

#10 mcross Nov 13, 2003 06:15 PM

I don't accually have a working controller yet. I have been testing with an industrial controller where I work. The controler I will be using is based on a Phillips chip #TDA 5145. These chips are extremely hard to get in small quantities. It should work on all small brushless, sensorless DC motors incluing LRKs. I don't know a whole lot about this chip except that I believe it is ideal for micro uses. It took me over a year to get painfully few samples.
Mike

#11 Ron van Sommeren Nov 17, 2003 11:25 AM

Five and half diy brushless ESC designs:
http://www.rcgroups.com/forums/showt...hreadid=140454

Met vriendelijke groet ;) Ron van Sommeren
diy outrunner brushless e-motor discussion.
Electric fly-in & lrk meet, June 27th, 2004, Nijmegen, the Netherlands.

#12 jeffs555 Dec 01, 2003 02:36 PM

I just looked at the Microchip AN857 design, and their sensorless version gets its timing by sensing the back emf on only one phase. All the other designs I have looked at, sense back emf on all three phases. Does anyone have any experience with the microchip design? I am using a different processor, and not a pic, but it would make for a smaller/lighter design to eliminate emf sensing on two of the phases. Anyone have enough experience to know if this would effect performance or efficiency?

Jeff

#13 billystiltner Dec 03, 2003 11:43 PM

Hey

Thanks Ron.
I have not had time to absorb the thread but will soon.

Jeff
I have not the experience with the controllers to answer but maybe try it out on a breadboard.

All

I have drawn up a PCB for a small controller using the TDA5144
20 pin controller. There are a few capacitor values that must be calculated Info is in the data sheets. Mostly the capacitors somehow control the adaptive commutation delay , startup oscillation, and then there is the timing capacitor. I am not well versed in Brushless motor physics to plug in the numbers to calculate the capacitor values so I figure Graham, Gail, and Ron you guys could be of great help here. Anyone else that could maybe help would be great.

I will post the formulas later as well as the PCB. The PCB should be the same regardless of capacitor values. I have to draw the PCB on the computer I have only drawn it up by hand so far.

Maybe the values given in the example circuit might work to control the motors that Graham and Gordon have designed as well as the motor that Mike Cross has designed.

I think that a voltage is what controls the speed of the controller
So I might have to find some way to transform the pulsed output from ESC of RXs to a proportional voltage. To test I might have something as simple as a capacitor or battery and POT but for practical aplication a PIC with analog output might be a better choice as the ripple of the capacitors charging and discharging might prove to be too much.

What would be a good 8 pin PIC with analog output and internal OSC?

I am off to carve a prop now and test some new equipment.

Billy

#14 jeffs555 Dec 04, 2003 04:33 PM

Billy,
Do you have a source for the TDA5144? It has been discontinued, and even the TDA5145 which is still in production would be hard to get. Most of these single chip brushless controllers are used in things like disk drives where they are bought in massive volumes. They are rarely available from distributors in quantities of less than 1000 at a time. Also, if you are planing to drive a small motor directly from the outputs of the TDA5144 be aware that you will waste significant voltage and power. The chip uses bipolar transistors, and the output voltage will be about 2 volts less than the supply voltage. If you power it directly from a 2 cell lipo battery, you will be wasting 25% of the voltage, and close to half of the power. Since most of the voltage loss is from the drop-out voltage, you could use a voltage booster to power the VP pin, so that it is above the motor voltage, but you would probably be better off buffering the outputs with Mosfets.

Jeff

#15 billystiltner Dec 04, 2003 05:17 PM

1 Attachment(s)
Jeff I do not have a source for them but maybe we can find some surplus part that has them in it for cheap or something to toy with.

Here is a PCB layout for the TDA5144AT.
I will update later for 5145 and also add some mosfets.
Not sure how the mosfets will work though since the controllor is sensorless. This is just a start and I have not calculated the values for the capacitors yet but info is in the datasheets.
It is pretty much the same as for the 5145 but 5145 has more pins. Since this chip is discontinued I guess I can rack this up as good experience for drawing a PCB. In order to be a stand alone board I guess this thing needs some way of varying the motor voltage and a Voltage booster if it's used with a single lipoly

Maybe we can find another single chip controller.


Have Fun
Billy


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