Our quad escs are now supporting 128K pwm when controlled with an STM F4 or equiv... also have "by RPM" pwm control supporting up to 16K - 128K pwm automatically varying based on motor rpm via DSHOT telemetry. Awesome!!
😁 I did a pwm controller for final project in college over 20yrs ago. High transient voltage spikes was my nemesis. Kept burning up mosfets under load. Learned later how capacitors on the output could have fixed that. I did get a passing grade 😄 Cheers
We have quadcopter ESCs that can go up to 96k. Higher pwm seems to be smoother and more efficient in real world testing. Lower pwm seems to give us more control. It is believed that comes from more braking power on lower pwm. I wonder if it would be possible for you can test ramp up time, braking, or something similar to see how pwm affects motor control? I understand that you might be limited by your equipment.
Hey Marty, thanks for the comment. I'd have to think about how to test the ramp up and braking vs PWM selection. What would you suggest to be a good motor/prop/cell count combo to be most similar to the average race drone? I think I would be limited on burst current, which would also be triggered upon braking current going in the reverse direction.
Totally off topic of this video. But I have a ? I am running a max 5 combo with a 800kv motor with 30/39 gearing in my K8 exb. I ran this setup a few day ago with 2of my 4s 6500 60c youme lipo batteries. With great temps and run time. Since then I got 2 4s 8000 100c power hobby batteries. I ran them threw the xmaxx one time. Stored them correctly. I charged them up today and threw them in the exb. It ran half the time than my smaller batteries do. My temps on Esc motor and all wires were 109° at most. I was ripping it threw a low cut field. When Lvc kicked in the batteries them selfs were around 140° And they were discharged all the way down to 3.30. Lvc Usually kicks in on all my other batteries at 3.6 or 3.5. Any ideas? And sorry for the long post hope you read this
@@RCexplained I will have to take them to my brothers house tomorrow and have them checked on his charger. The charger I use currently is a venom duo Pro and unfortunately I do not have that function on this charger. I will get back with you as soon as possible. I really appreciate you taking time to reply to my Question. Again thank you
I'm driving a motor with pwm modulation too. But I can't find how much efficiency is when pwm modulation. How do you calculate the power for PWM modulation? Do you have a documentation or a website for this?
I see the sensor specs on the side and it shows 14 pole which is a typical quad copter motor. Don't most rc cars run 4 pole? If quad copter they are running up to 96khz and use variable pwm. What motor were you testing?
So, does the pwm rate limit the top rim possible from a high pole count motor? Say 8khz and a 12 pole motor, does that imply a max switching rate to match 40000 rpm? What happens when the motor will turn faster than the max switching rate? Or is the ability to switch more so a limit of the hardware in the esc?
The pwm rate would limit the top speed, but it’s not a hard limit, just that after a certain speed the signal would not match what the motor needs. The other factor is the update rate, which may be slower, and would have the same limiting effect by being inaccurate.
@@brodymiller9299 I think you hit it perfectly. The motors and esc I was running seemed to miss sync at high rpm and high load. I ended up changing esc to a much faster pwm capable system and they run fine now.
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Our quad escs are now supporting 128K pwm when controlled with an STM F4 or equiv... also have "by RPM" pwm control supporting up to 16K - 128K pwm automatically varying based on motor rpm via DSHOT telemetry. Awesome!!
😁
I did a pwm controller for final project in college over 20yrs ago. High transient voltage spikes was my nemesis. Kept burning up mosfets under load. Learned later how capacitors on the output could have fixed that. I did get a passing grade 😄
Cheers
That is a great story Patrick! Glad to hear you got the passing grade! Just getting the circuit to function correctly is majority of the battle.
So higher pwm will be smoother and more efficient. Nice 👍
Great explanation video! What software do you use to plot the real-time data?
Very clear explanation about PWM !!
Thanks for the comment nelissuh !
We have quadcopter ESCs that can go up to 96k. Higher pwm seems to be smoother and more efficient in real world testing. Lower pwm seems to give us more control. It is believed that comes from more braking power on lower pwm. I wonder if it would be possible for you can test ramp up time, braking, or something similar to see how pwm affects motor control? I understand that you might be limited by your equipment.
Hey Marty, thanks for the comment. I'd have to think about how to test the ramp up and braking vs PWM selection. What would you suggest to be a good motor/prop/cell count combo to be most similar to the average race drone? I think I would be limited on burst current, which would also be triggered upon braking current going in the reverse direction.
Good video, excuse me while I fire up my synthesizer.
Totally off topic of this video. But I have a ? I am running a max 5 combo with a 800kv motor with 30/39 gearing in my K8 exb. I ran this setup a few day ago with 2of my 4s 6500 60c youme lipo batteries. With great temps and run time. Since then I got 2 4s 8000 100c power hobby batteries. I ran them threw the xmaxx one time. Stored them correctly. I charged them up today and threw them in the exb. It ran half the time than my smaller batteries do. My temps on Esc motor and all wires were 109° at most. I was ripping it threw a low cut field. When Lvc kicked in the batteries them selfs were around 140° And they were discharged all the way down to 3.30. Lvc Usually kicks in on all my other batteries at 3.6 or 3.5. Any ideas? And sorry for the long post hope you read this
What are the internal resistances of all your packs. -Average per cell.
@@RCexplained I will have to take them to my brothers house tomorrow and have them checked on his charger. The charger I use currently is a venom duo Pro and unfortunately I do not have that function on this charger. I will get back with you as soon as possible. I really appreciate you taking time to reply to my Question. Again thank you
I'm driving a motor with pwm modulation too. But I can't find how much efficiency is when pwm modulation. How do you calculate the power for PWM modulation? Do you have a documentation or a website for this?
No, sorry don't have any resources for this.
Great info sir 👍
So nice of you
Good info 👍🏻👍🏻
Thanks 👍
I see the sensor specs on the side and it shows 14 pole which is a typical quad copter motor. Don't most rc cars run 4 pole? If quad copter they are running up to 96khz and use variable pwm. What motor were you testing?
This was an airplane motor
So, does the pwm rate limit the top rim possible from a high pole count motor? Say 8khz and a 12 pole motor, does that imply a max switching rate to match 40000 rpm? What happens when the motor will turn faster than the max switching rate? Or is the ability to switch more so a limit of the hardware in the esc?
The pwm rate would limit the top speed, but it’s not a hard limit, just that after a certain speed the signal would not match what the motor needs. The other factor is the update rate, which may be slower, and would have the same limiting effect by being inaccurate.
@@brodymiller9299 I think you hit it perfectly. The motors and esc I was running seemed to miss sync at high rpm and high load. I ended up changing esc to a much faster pwm capable system and they run fine now.
Do more expensive esc have higher pwm?
It's possible!
Does this apply to brushed system as well...?
I would expect, yes
@@RCexplained thank you for your answer
I have to increase my frequency on my jetboard because I need more power