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Old Nov 06, 2002, 04:34 AM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
stumax,

>Can you explain your method of rotor position sensing in the controller?

I have translated to English. I hope you could understand by attached file.

>Are you just sensing the zero crossing of the unused phase, or
>the second differential to get the inflection point?

Sorry, I forgot the detail. Read my program.
Probably, my software could find the miss sensing= miss output code and check it again. I could not develop other methods.

>do you pwm the fets on startup to reduce current draw?

Yes, I do. Just reduced duty. Read my program.
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Last edited by Takao Shimizu; Nov 06, 2002 at 04:46 AM.
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Old Nov 06, 2002, 09:15 PM
Grand Poobah of Nothing
Trizza's Avatar
Once Australia, now Finland
Joined Feb 2001
1,022 Posts
Nice.
Did you end up making it with all SMD? How much does your flying version weigh?
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Old Nov 06, 2002, 10:16 PM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
Trizza,

>Did you end up making it with all SMD?

No, I did not.
My lightest SMD is for 2 pole brushless/Sensorless/Slotless motor.

>How much does your flying version weigh?

You can imagine the weigh with attached file. Very heavy.
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Last edited by Takao Shimizu; Nov 08, 2002 at 07:30 AM.
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Old Nov 06, 2002, 10:20 PM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
Flying my motor on last Sunday.

I am developping new only one sheet plywood and no-rib wing. The aircraft is $3 except film as you see. The wheels are plywood, also.
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Last edited by Takao Shimizu; Nov 06, 2002 at 10:32 PM.
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Old Nov 06, 2002, 10:29 PM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
My lightest SMD driver

My lightest SMD board is for 2 pole brushless/Sensorless/Slotless motor.
This is under development to make sensorless 2 pole brushless motor driver circuit.
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Old Nov 07, 2002, 08:54 AM
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ssatoru's Avatar
Chiba, Japan
Joined Jan 2002
1,044 Posts
Re: Flying my motor on last Sunday.

I am developping new only one sheet plywood and no-rib wing. The aircraft is $3 except film as you see. The wheels are plywood, also. [/QUOTE]

It is good to see here, Mr. Diode! Although a bit off subject, there is an interesting carbon wing project is going on.
http://www.rcgroups.com/forums/showt...threadid=61956

I need to visit your field to see them.

ssatoru @ Urayasu
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Old Nov 07, 2002, 07:54 PM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
What a small world!?

Hi, ssatoru@Urayasu,

I was flying near South end of Tokyo Disney Land.
Urayasu is 15 min. drive away!

an interesting carbon wing project
Very interesting. I have another a plan for micro plane carbon pipe truss design as attached file.

>I need to visit your field to see them.
Sure, I hope see you next Sunday.
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Old Nov 11, 2002, 01:11 AM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
Inner magnet rotor slot type Y winding configuration

The attached file shows slot type brushless motor Y winding.
There are six phase in 3 wire connection to speed controller, and each phase has one zero voltage applied wire as switching wave form shows.
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Old Nov 13, 2002, 12:30 PM
X-Era Motors
DavidB.'s Avatar
Newport, NC
Joined Jan 2002
2,225 Posts
WOW,
This is an amazing accomplishment. I along with many others have been waiting for a DIY Brushless controller design for some time. The only problem is that I lack the experience necessary to design the circuit board. Is there any way to obtain more information on the PCB construction and layout (close up pictures/schematics)? Once again, thankyou very much for providing us with this design. I am allready gathering the parts necessary to build my own .

David Bloomfield
http://www4.ncsu.edu/~dsbloomf
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Old Nov 13, 2002, 07:12 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,575 Posts
Quote:
Originally posted by DavidB.
... I along with many others have been waiting for a DIY Brushless controller design for some time....
Here's another one:
http://www.aerodesign.de/peter/2001/...DY-BL_eng.html

Met vriendelijke groet Ron van Sommeren
LRK homebuilt outrunner e-motor discussion group.
Electric fly-in & lrk meet, June 22nd, 2003, Nijmegen, the Netherlands.
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Old Dec 07, 2002, 04:01 AM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
stator construction

radix2,

>do you have any pictures of your stator construction?

Here is my new winding construction.
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Old Dec 11, 2002, 07:44 AM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
Details

*System Outline
This explanation is for Brushless and Sensorless DC motor driver with power control of RC radio Rx interface schematic.

The brushless motor has no-brush contact resistance, thus it has good power efficiency and long life, also, more input power capability is available by no brush melt down trouble.
"Sensorless" means that there are no-magnetic sensors as hall device to detect magnet rotation position in the motor. Only 3 power (thick) wire cords are needed to interface the 3-phase brushless motor.

When someone sees my hand made plywood case looking very cheap Brushless/Sensorless/Slotless motor, they have asked me (and e-mailed me after wrote here,) "Does this turn?" every time. And I have to explain the details with over 5 minutes and never understand (without configures). That is why I am writing this to cut waste of my lifetime.

*Free run to sense the rotator position
"Sensorless" is not correct term. The sensing circuit exists on the schematic by OP amps and the sensors are drive coils.
While rotate the motor, the rotating magnet generates the voltage into the drive coil as electric power generator. This is why power current is reduced while motor is running. And this means the generated (phase) waveform should be applied as drive power voltage waveform. To control like this digitally, the drive timing and sensing timing is separated by time-share control as sampling control.

The sensing circuit details and formula was shown in this forum before. 3 of OPamps as comparators generate adequate 3phase drive signal phase pattern code while motor free rotating by CPU free run sampling control.
As the sensing comparator circuit detects the motor magnate rotate position after sampling all FET off sampling timing (min. about 35uS at full power) edge while motor free runs (through 3 drive wires), also the motor power controlled by (every) duty cycle according to Rx signal output pulse width.
The (un-synchronized) free run (sampling) time is needed even full power condition to sense the rotor position every time.

There is all-power FET switched off timer function in the main program.
---------------------------------------------
free_run_tim:
set_off_timer: rcall P_FET_off_fast ;adjust opt. Coupler device delay timing
mov duty_time,on_time ;timer0 setting data setting
out TCNT0,duty_time ;Do not confuse. off-timing is on_time data, until timer0 over flow!

tim_set: clr timset ;Clear timer0 timeover flag
off_phase: sbrs timset,0 ;Skip if timer0 overflow is occurred
rjmp off_phase ;wait loop until timer0 overflow

get_sense: in r_sense,PIND ;PortD bit0,1,2 are connected OPamps.
andi r_sense,0b00000111 ;get rotate data from sensor circuit
ret ;return from sub routine

TO BE CONTINUED.

Attached the sampling oputput data and one of motor terminal waveform.
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Old Dec 11, 2002, 08:20 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,575 Posts
Re: Details

Quote:
Originally posted by Takao Shimizu
*... When someone sees my hand made plywood case looking very cheap Brushless/Sensorless/Slotless motor, they have asked me (and e-mailed me after wrote here,) "Does this turn?" every time. And I have to explain the details with over 5 minutes and never understand (without configures). That is why I am writing this to cut waste of my lifetime ...[/img]
Make a short movie of your motor running and put it on your site. E.g. http://groups.yahoo.com/group/lrk-to.../files/lrk.wmv
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Old Dec 14, 2002, 05:28 AM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
Re: Re: Details

Thanks Ron,
>Make a short movie of your motor running and put it on your site.

It is good idea.
I tried put on the movie in here(no charge place for big files).

http://www.geocities.co.jp/Technopolis/6767/
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Old Dec 15, 2002, 11:52 AM
Registered User
Tokyo, Japan
Joined Nov 2002
858 Posts
Sensor-less sampling technique.

There is the inductive kick high voltage power from the drive coil energy when switching OFF the MOSFETs at the sart of sampling timing. Decrease the turning off speed to avoid this noise interference and protect the FETs and speed up the sampling. To do this, I just put a resister on the power FET gate pin which may have a few thousand pF input capacitance to make low pass filter.
Another problem is gResonanceh of driver coils. RC brushless motor coil is a few turned only to get power from low voltage battery. This small winding generates a few MHz resonance, which is measured when I run this motor. Also, This makes common noise to input of OP amp. This is why I put the capacitors at Op ampsf inputs to GND, not on +- inputs.

You must check these noise by oscilloscope before decide the sampling gate timing.

TO BE CONTINUED.
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Last edited by Takao Shimizu; Dec 20, 2002 at 06:44 PM.
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