PWM Frequency
jgeidl
run you motors?
Jim, K6JMG
Ralph Gnauck
From: jgeidl <but...@gmail.com>
To: HomeBrew Robotics Club <hbrob...@googlegroups.com>
Sent: Wed, February 17, 2010 3:48:41 PM
Subject: [HBRobotics] PWM Frequency
What PWM frequency are you guys using with your various H-bridges to
run you motors?
Jim, K6JMG
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James M.(Jim) Geidl
Jim, K6JMG
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From: hbrob...@googlegroups.com [mailto:hbrob...@googlegroups.com] On Behalf Of Ralph Gnauck
Sent: Wednesday, February 17, 2010 3:56 PM
To: hbrob...@googlegroups.com
Subject: Re: [HBRobotics] PWM Frequency
Alan Marconett
Specs say max 10KHz. I didn’t see a PDF manual to download.
Alan KM6VV
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giuliano carlini
James M.(Jim) Geidl
James M. (Jim) Geidl,
K6JMG
www.spinochio.com
3528 Liberty Ct.
Antioch, CA 94509
925 778-8958
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From: hbrob...@googlegroups.com [mailto:hbrob...@googlegroups.com] On Behalf Of Alan Marconett
Sent: Wednesday, February 17, 2010 4:29 PM
James M.(Jim) Geidl
Jim, K6JMG
www.spinochio.com
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From: hbrob...@googlegroups.com [mailto:hbrob...@googlegroups.com] On Behalf Of giuliano carlini
Sent: Wednesday, February 17, 2010 4:32 PM
Alan Marconett
Hi Jim,
Thanks for the URLs.
I didn’t see a XTAL on the board, but those things are getting so tiny now…
20KHz is what I try for. I’m playing with a Mark III board, to which I can add a “sensor” board with two SN754410NE dual H-bridge chips on it (adds $30). But right now I’m suffering through getting CCS ‘C’ code translated to HighTech C. Initially I’m going to use modified R/C servos with wheel encoders, later I’ll try the sensor board on D/C motors. I’ll try to figure out what rate they’re running the PWM for the DC motors at. I’m still stuck in nested PID code for the R/C motors!
giuliano carlini
James M.(Jim) Geidl
Jim, K6JMG
www.spinochio.com
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Sent: Wednesday, February 17, 2010 5:02 PM
James M.(Jim) Geidl
Jim, K6JMG
www.spinochio.com
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Sent: Wednesday, February 17, 2010 5:07 PM
Alan Marconett
Hi Jim,
You get easily modified R/C servos with the kit. The sensor board can drive the DC motors. I figured I’d get a chance to play with both one time or another…
The PWM rate is 19,531 KHz!
Alan KM6VV
On Behalf Of James
M.(Jim) Geidl
Steven Nelson
Motor links:
Speed controller links:
| Basic info | Advanced info | |||||||||
| Controller | Channels | Voltage | Continuous current | PWM Frequency | Sources | FET Type | FETs per leg | FET VDSS | FET RDS | FET ID(1) |
| 48330 | 1 | 14.5 V - 58 V | 330 A | 16 kHz | Team Whyachi, The Robot MarketPlace | |||||
| Ampflow (1 channel) | 1 | 12 V - 40 V | 320 A | 16 kHz | AmpFlow.Com, The Robot MarketPlace | 8 | ||||
| Ampflow (2 channel) | 2 | 12 V - 40 V | 160 A | 16 kHz | AmpFlow.Com, The Robot MarketPlace | 4 | ||||
| Icon H-Bridge | 1 | 1 V - 40 V | 12 A | 19.2 kHz | Active Robots | IRF8027S | 1 | 75 V | 0.013 Ω | 82 A |
| MC1-HV | 1 | 4 V - 42 V | 400 A | up to 16 kHz (2) | Robot Solutions, The Robot MarketPlace | IRF1407 | 8 | 75 V | 0.0078 Ω | 130 A |
| ML-ESC10 | 1 | 6 V - 50 V | 10 A | 500 Hz | The Robot MarketPlace | |||||
| OSMC | 1 | 14 V - 30 V | 160 A | up to 32 kHz (2) | Robot Power, The Robot MarketPlace | IRF1404 | 4 | 40 V | 0.004 Ω | 202 A |
| OSMC | 1 | 14 V - 50 V | 160 A | up to 32 kHz (2) | Robot Power, The Robot MarketPlace | IRF1405 | 4 | 55 V | 0.0053 Ω | 169 A |
| RDFR 21 | 2 | 4.5 V - 30 V | 14 A | 338 Hz, 21.6 kHz | VANTEC, The Robot MarketPlace | |||||
| RDFR 22 | 2 | 4.5 V - 30 V | 20 A | 338 Hz, 21.6 kHz | VANTEC, The Robot MarketPlace | |||||
| RDFR 23 | 2 | 4.5 V - 30 V | 30 A | 338 Hz, 21.6 kHz | VANTEC, The Robot MarketPlace | IRF1010N | 2 | 55 V | 0.011 Ω | 85 A |
| RDFR 33 | 2 | 9 V - 43 V | 35 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC, The Robot MarketPlace | IRFZ44 | 6 | 60 V | 0.028 Ω | 50 A |
| RDFR 36E | 2 | 9 V - 43 V | 60 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC, The Robot MarketPlace | |||||
| RDFR 38E | 2 | 9 V - 32 V | 80 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC | 6 | ||||
| RDFR 42 | 2 | 32 V - 60 V | 20 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC | |||||
| RDFR 43E | 2 | 32 V - 60 V | 35 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC | |||||
| RDFR 47E | 2 | 9 V - 55 V | 75 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC, The Robot MarketPlace | |||||
| RDFR 61 | 2 | 50 V - 140 V | 10 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC | |||||
| RDFR 61E | 2 | 50 V - 140 V | 15 A | 169 Hz, 338 Hz, 21.6 kHz | VANTEC | |||||
| RoboteQ AX2550 | 2 | 12 V - 40 V | 120 A | 16 kHz | RoboteQ, The Robot MarketPlace, NPC Robotics | 2 | ||||
| RoboteQ AX2550HE | 2 | 140 A | 4 | |||||||
| RoboWars IBC | 2 | 4 V - 36 V | 50 A | RoboWars, The Robot MarketPlace | IRF1405 | 1 | 55 V | 0.0053 Ω | 169 A | |
| RS80D | 2 | 4 V - 42 V | 80 A | Robot Solutions, The Robot MarketPlace | IRF1407 | 2 | 75 V | 0.0078 Ω | 130 A | |
| RSGSS | 2 | Robotic Sporting Goods | IRFZ44V | 3 | 60 V | 0.0165 Ω | 55 A | |||
| RSGTX | 2 | 15 V - 24 V | 60 A | Robotic Sporting Goods | 3 | |||||
| Scorpion | 2 | 4.8 V - 22 V | 2.5 A | Robot Power, The Robot MarketPlace | ||||||
| Sidewinder | 2 | 6 V - 50 V | 80 A | Robot Power | 2 | |||||
| Thor 883 | 1 | 6 V - 30 V | 120 A | 120 Hz | The Robot MarketPlace | ISL9N303AP3 | 3 | 30 V | 0.0026 Ω | 75 A |
| Victor 883 | 1 | 6 V - 30 V | 60 A | 2 kHz | IFI Robotics, The Robot MarketPlace, Team Delta | IRL2203N | 3 | 30 V | 0.007 Ω | 116 A |
| Victor 884 | 1 | 6 V - 15 V | 40 A | 120 Hz | IFI Robotics | IRL3103 | 3 | 30 V | 0.012 Ω | 64 A |
| Victor 885 | 1 | 6 V - 30 V | 120 A | 120 Hz | IFI Robotics, The Robot MarketPlace | 3 | 30 V | 0.0028 Ω | 210 A | |
| Victor-HV 36V | 1 | 12 V - 42 V | 120 A | 120 Hz | IFI Robotics, The Robot MarketPlace | 4 | ||||
| Victor-HV 48V | 1 | 12 V - 60 V | 90 A | 120 Hz | IFI Robotics, The Robot MarketPlace | 4 | ||||
1. Typically the FET case's ability to dissipate heat limits this number to around 40 A per FET.
2. The PWM frequency for this controller is determined by one of the following interfaces:
MOB: 2 kHz, 4 kHz, 16 kHz, 32 kHz
uMOB: 3 kHz
uRRC 2.0:
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James M.(Jim) Geidl
Jim, K6JMG
www.spinochio.com
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From: hbrob...@googlegroups.com [mailto:hbrob...@googlegroups.com] On Behalf Of Steven Nelson
Sent: Wednesday, February 17, 2010 5:48 PM
giuliano carlini
Peter Nau
Anyway, this is just one factor. It applies because a large rotating mass smooths out the PWM impulse vibrations better than a small mass does. The mass acts just like a low-pass filter, where the bigger the mass, the lower the filter cut-off frequency. The other factors y'all have mentioned apply, too: electronics, audio, resonance, noise, motor specs, etc.
Ignoring those other factors, if the system is smooth enough when you run it at the low end of speed, then the PWM frequency is probably high enough. If it's jerky, then higher frequency might help.
As an interesting (to some people, anyway :-) aside, a "Class D" audio amplifier is actually a PWM amp with a low-pass filter on the output. I read that they work well and are very efficient. Same general principal.
Cheers,
~Peter
James M.(Jim) Geidl
Jim, K6JMG
www.spinochio.com
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From: hbrob...@googlegroups.com [mailto:hbrob...@googlegroups.com] On Behalf Of Peter Nau
Sent: Wednesday, February 17, 2010 6:57 PM
Nathaniel Lewis
80 KHz if you use 8 bit pwm. Don't go pumping either of those into one
of Pololu's drivers, they freak out at anything over 10 KHz. My big
driver that I got at Pololu almost fried with a little radioshack motor
on 20 KHz pwm.
Nathaniel
James M.(Jim) Geidl
Jim, K6JMG
www.spinochio.com
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> -----Original Message-----
> From: hbrob...@googlegroups.com
> [mailto:hbrob...@googlegroups.com] On Behalf Of Nathaniel Lewis
> Sent: Wednesday, February 17, 2010 8:34 PM
> To: hbrob...@googlegroups.com
> Subject: Re: [HBRobotics] PWM Frequency
>
Jack Buffington
understanding of why you would pick one PWM frequency over another is
as follows, at least for a solenoid or motor where you are alternating
the direction of the power through the motor on every PWM cycle. For
example, if you were driving it with a 50% duty cycle, then your motor
would be stopped. 100% duty cycle would get you full speed one way.
0% duty cycle would get you full speed the other way.
If you go too high in frequency, you will spend a lot of time with
your MOSFETs half on. Your efficiency goes down and you risk burning
up your MOSFETs.
If you go too low in frequency, your MOSFETs will be fine but you will
end up saturating your motor's coils which won't give you any
additional magnetic force out of them but will put the maximum
possible power through the motor. Your motor will end up getting
hot. Efficiency goes down.
Of course, some motors like coreless motors have very low inductance
so the technically proper frequency would be very high. Higher than a
lot of H-bridges can handle. You can correct for that by adding an
inductor in series with it. This will bring the ideal frequency
down.
Of course, unless you are working with a really big motor where lots
of heat could be an issue or have efficiency issues that you need to
attend to, I would just pick something out of the audible range and
call it a day if your H-bridge can handle that frequency.
-Jack
Nathaniel Lewis
they were put under stress(like driving up a hill). It used power wheels
motors. They are big and beefy with a 30 Amp stall current but lugged
around the 60 pound robot with ease.
-----Original Message-----
From: hbrob...@googlegroups.com [mailto:hbrob...@googlegroups.com] On
-Jack
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