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Feb 17, 2004, 07:40 AM
Impossible? Hah!
KreAture's Avatar
Discussion

BLDC controller


Well, I wanna be the one to start up the new thread in the DIY forums

To iterate, here's the old thread:
https://www.rcgroups.com/forums/show...hreadid=181247

I won't repost any of the old stuff, let's get new stuff in!

I am planning to make a prototype circuit with a programmer buildt in for easy re-flashing now. It will only be the basic module and not have any motor peripherals. I was thinking of using a pinheader and linking it to the FET-board so that I may do changes on the design more quickly.

I will be experimenting with heavy filtering of the EMF signal with rpm-based table-correction of the signal phase. This should make it possible to design a very high commutation-rate controller without the need for fast ADC.
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Feb 17, 2004, 11:41 PM
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Mr DIY's Avatar
So Kreature, what have you done so far? Have you managed to breadboard any circuitry yet? I am more than a little curious to see how your idea is going to work.

Brian
Feb 18, 2004, 05:35 AM
Impossible? Hah!
KreAture's Avatar
I have simulated the filter to stry and eliminate as much phase delay as possible. The best I got so far was 3 deg predictable phase shift spread over the last 7-10.000 rpm. (Was targeting 10.000 rpm max on 12 magnet motor. = 6000 commutations / second.)
Feb 18, 2004, 05:35 AM
Impossible? Hah!
KreAture's Avatar
Oh, and I don't breadboard. I etch and smt. Faster and neater.
Feb 18, 2004, 06:00 AM
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Mr DIY's Avatar
Quote:
Oh, and I don't breadboard. I etch and smt. Faster and neater.
I do the same... however it was meant more as a figure of speech as in ...have you put anything in hardware yet. You answered anyway
Feb 19, 2004, 03:18 PM
Registered User

Re: BLDC controller


Quote:
Originally posted by KreAture
Well, I wanna be the one to start up the new thread in the DIY forums

To iterate, here's the old thread:
https://www.rcgroups.com/forums/show...hreadid=181247

I won't repost any of the old stuff, let's get new stuff in!

I am planning to make a prototype circuit with a programmer buildt in for easy re-flashing now. It will only be the basic module and not have any motor peripherals. I was thinking of using a pinheader and linking it to the FET-board so that I may do changes on the design more quickly.

I will be experimenting with heavy filtering of the EMF signal with rpm-based table-correction of the signal phase. This should make it possible to design a very high commutation-rate controller without the need for fast ADC.
I have received my BLDC PCBs and will start populating the bord in a few days. I use the Microchip ICD2 for in curcuit programming. This eliminates the need for a programmer on the BLDC and allows debugging in the actual target application. I am starting with AN857 and hope to move to dsPICs when they are available.
Feb 19, 2004, 03:32 PM
Impossible? Hah!
KreAture's Avatar
Cool. I am currently redesigning my regular ESC. Making it more robust. (Removing a bit more noise from the system and getting the LVC working right. It will provide a platform for my brushless version.
Feb 19, 2004, 11:56 PM
Registered User
Mr DIY's Avatar
Well seeing we are giving current status reports, I am currently adding in/testing all that laborious software that does all the start up checks.. like look for correct PWM sequence from Rx, Battery voltage / FET driver voltage checks, Low voltage cut off, arming sequences/user programming ect.
My latest PCB is almost fully populated .. just needs the FET drivers and FPGA device. Still awaiting the FETs I ordered though.

Mr Takao.

I ran some tests on the ADC module and over-clocked it progressively up to 2MHz while watching the stream of samples sent to my PC. Samples where within 1 bit resolution for an 8-bit sample on a RX PWM generated voltage. Not bad for device that is clocked 10 times faster than the specified spec. I am yet to try the 4MHz clock as you have done, but I am more than happy with the 6 odd uS conversion time I am getting. It has allowed me to totally rethink how I am doing some routines.

Brian
Feb 21, 2004, 10:00 AM
Registered User
MAVA's Avatar
Kreature

Here is somthing that may help you with the journey of the DIY Brushless Controller.

Microchip application note AN857

http://www.microchip.com/1010/suppdo...n857/index.htm

Link to all the Motor application notes.

http://www.microchip.com/1010/suppdo...ntes/index.htm

Martin
Feb 21, 2004, 07:55 PM
"Simplify, then add lightness"
I had looked at AN587, and was really curious about the sensorless design they show. Most other designs sense all three phases, but their sensorless design has input from only one phase . If the motor is running at a fairly constant speed, this should be fine and save a few components. I would wonder however, how well it would handle startup or rapid speed changes.

Jeff
Feb 21, 2004, 09:11 PM
Registered User
Quote:
Originally posted by jeffs555
I had looked at AN587, and was really curious about the sensorless design they show. Most other designs sense all three phases, but their sensorless design has input from only one phase . If the motor is running at a fairly constant speed, this should be fine and save a few components. I would wonder however, how well it would handle startup or rapid speed changes.

Jeff
I am in the process of building AN857. I will let you know how it works.
Feb 22, 2004, 09:18 AM
Impossible? Hah!
KreAture's Avatar
MAVA
I've read all their appnotes before, as well as all ST and Motorola notes. The challenge is not to get it to work. I know a lot of how it should and can be done. I am simply trying to get it done with a more elegant solution.
Mar 01, 2004, 12:18 AM
Registered User
Mr DIY's Avatar
Hmm ... all is quiet here. Anybody make progress?

I myself, waiting for last 2 of my outstanding components, the low drop regulator and most importantly, FETs. Should have them this week.
Mar 01, 2004, 05:34 AM
Impossible? Hah!
KreAture's Avatar
I had great success with the new regulator I tested. 1.15v drop 1 Amp. Should suffice. Now to make a new prototype with ICSP header...
Mar 01, 2004, 07:07 AM
Registered User
Mr DIY's Avatar
Takao write - previous thread
Quote:
I had found one interesting chip.

http://www.silabs.com/products/micr...xsig_matrix.asp

The development tool is $99!
Ooh! nice 8051 based micros. Very similar to the Analog Devices ADuc812 range. I have a few of the AD devices left, but found them very expensive when compared to the Mega 8. The thing that they have, as do the devices listed above, are the 12 bit DACs. They come in very usefull. Any clues as to cost Takao?


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