difference between 2-quadrant and 4-quadrant speed controllers
difference between 2-quadrant and 4-quadrant speed controllers
(OP)
What is the difference between 2-quadrant speed controller and 4-quadrant in brushless DC motor controller?
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difference between 2-quadrant and 4-quadrant speed controllers
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RE: difference between 2-quadrant and 4-quadrant speed controllers
The other two quadrants refer to the motor now being driven by something and the the power being returned to the controller for storage or dissipation - the motor acting as a generator.
Keith Cress
kcress - http://www.flaminsystems.com
RE: difference between 2-quadrant and 4-quadrant speed controllers
I have another two question:
1- What about 1-Quadrant motor driver?
2- If I want to control the braking mode for the motor as well as the motor mode, what is the suitable motor driver "1-Q, 2-Q or 4-Q"?
RE: difference between 2-quadrant and 4-quadrant speed controllers
If you want both directions, motor/braking, you'd need a four quadrant controller. If you just want one direction, theoretically, you'd need only a 2 quadrant but I can't say I've ever seen one that is the 'correct' two qudrants.. Normally I see the two quadrants as being only direction 'forward and reverse' not motor and generate.
Keith Cress
kcress - http://www.flaminsystems.com
RE: difference between 2-quadrant and 4-quadrant speed controllers
Braking would require a 2 quadrant drive, but not the two quadrants you get from a reversing type!
Define the quadrants:
1 - forward, motoring
2 - reverse, motoring
3 - reverse, generating
4 - forward, generating
You need a regenerative drive to effect braking, which likely will be a four quadrant drive even if you don't want the reversing feature.
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RE: difference between 2-quadrant and 4-quadrant speed controllers
What do you mean by " Normally I see the two quadrants as being only direction 'forward and reverse' not motor and generate"?
@SottyUK
What do you mean by "Braking would require a 2 quadrant drive, but not the two quadrants you get from a reversing type!"?
I am a little bit confused. Is 2-quadrant drive used to control motor in forward and reverse direction while 4-quadrant used for motor/regenerative drive (motor/generator)?
RE: difference between 2-quadrant and 4-quadrant speed controllers
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RE: difference between 2-quadrant and 4-quadrant speed controllers
There are 4 quadrants:
#1 = Motor CW
#2 = Regen CW
#3 = Motor CCW
#4 = Regen CCW
THEN there are either 1, 2 or 4 quadrant drives.
A drive that is 1Q is #1 only
A drive that is 2Q can be #1 + #3, or it can be #1 + #2. Saying just "2 quadrant" is technically insufficient to differentiate. I have always said "2Q reversing" or "2Q Regen (or Braking)"
A 4Q drive is of course #1, #2, #3 and #4 and so needs no further qualification.
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RE: difference between 2-quadrant and 4-quadrant speed controllers
I have another question regarding to 4-q driver. Could I use 4-Q drive to work as bidirectional amplifier to actuate the motor in Q-1 and Q-3, and recharge a battery in Q-2 and Q-3?
RE: difference between 2-quadrant and 4-quadrant speed controllers
To add to the confusion, VFDs are sometimes called 4Q drives if they have a braking resistor instead of using proper regeneration. The rationale for this is that all VFDs can drive FW and BW, i.e. Q1 and Q3. With the braking resistor, they can also brake in Q2 and Q4.
The marketing people then say that it can do everything that a genuine 4Q drive can - so it is a 4Q drive.
What they do not tell you is that the braking power is limited by the resistor and - more important - you do not regenerate. So all the braking energy, that you planned to 'sell back' to the grid is lost as heat in the resistor.
Gunnar Englund
www.gke.org
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RE: difference between 2-quadrant and 4-quadrant speed controllers