3phase PWM variable speed motor

D

~Dude17~

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I took apart a DVD-ROM drive for the heck of it and the control LSI is
amazing stuff.

The driver chip has everything to directly drive all the mechanical
parts in a CD-ROM drive from loading tray, focus, tracking, sled and
the spindle motor. I find the spindle motor control the most
fascinating.

http://www.rohm.com/products/databook/optdisc/pdf/bd7902cfs.pdf

The chip controls the spindle motor using three phase PWM and reading
the controller documentation leads me to believe the thing can be
controlled somehow with pin 24.

The range is rather wide 230RPM while playing back audio CD at outer
diameter and about 10,000RPM at 48x CAV mode. The chip can also apply
reverse torque to quickly bring the disc to stop.

Is it difficult to make a variable speed drive using the spindle motor
and the LSI pulled from a DVD-ROm drive to let me run the motor
anywhere from 280 to 10,000RPM outside of the original drive? It
would surely make a cool project part.


If this sophisticated control can be built into a $20 DVD-ROM drive,
how expensive would it be to integrate a similar controller with
beefier drive circuit to drive a motor in few hundred watt to a few
kilowatt range?
 
You are in the 19th century.The germans have used this since 1990.The ICE
train (InterCityExpress) has 13,000 HP, probably 8 traction motors and 2
"locomotives" (see www.db.de if you can read german).The motors are
asynchronous, three-phase squirrel cage and of course they must have
sufficient torque to pull the train at stop and enough rpm to reach the
maximum speed of 200 km/h.The cetenary system is 15 kV 16 2/3 Hz.Of course,
there's such a drive as in the DVD.In normal electric locomotives there's a
motor with brushes and excitation in series (like the one your drill has or
your mixer, the one you make the ice-cream) and a transformer with 18
taps.To start the train, you need high current and low voltage.For maximum
speed, you need high voltage and sufficient current.These motors are
directly coupled on the wheels.

--
Dimitris Tzortzakakis,Iraklion Crete,Greece
major in electrical engineering
freelance electrician
dimtzort AT otenet DOT gr
? "~Dude17~" <dude17@sacbeemail.com> ?????? ??? ??????
news:b959931f.0409102228.5a14eff2@posting.google.com...
X-No-Archive: Yes

I took apart a DVD-ROM drive for the heck of it and the control LSI is
amazing stuff.

The driver chip has everything to directly drive all the mechanical
parts in a CD-ROM drive from loading tray, focus, tracking, sled and
the spindle motor. I find the spindle motor control the most
fascinating.

http://www.rohm.com/products/databook/optdisc/pdf/bd7902cfs.pdf

The chip controls the spindle motor using three phase PWM and reading
the controller documentation leads me to believe the thing can be
controlled somehow with pin 24.

The range is rather wide 230RPM while playing back audio CD at outer
diameter and about 10,000RPM at 48x CAV mode. The chip can also apply
reverse torque to quickly bring the disc to stop.

Is it difficult to make a variable speed drive using the spindle motor
and the LSI pulled from a DVD-ROm drive to let me run the motor
anywhere from 280 to 10,000RPM outside of the original drive? It
would surely make a cool project part.


If this sophisticated control can be built into a $20 DVD-ROM drive,
how expensive would it be to integrate a similar controller with
beefier drive circuit to drive a motor in few hundred watt to a few
kilowatt range?
Click to expand...
 
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