Search found 283 matches

by peters
Feb 01 2020 11:29am
Forum: Motor Technology
Topic: Cheap FOCer 2 (Open-source, Low-cost, VESC 6 based ESC) (Prototyped. Materials have arrived for a test batch)
Replies: 41
Views: 3889

Re: Cheap FOCer 2 (Open-source, Low-cost, VESC 6 based ESC) (Prototyped. Materials have arrived for a test batch)

Very nice waveforms, indeed! The overshoot (spike) at turn-off is absolutely normal, because the current changes from 50A to 0 during that time and the overshoot voltage above the DCbus is L*di/dt. L is the output loop inductance that is an inherent attribute of the circuit. In fact the area under t...
by peters
Jan 11 2020 2:34am
Forum: Motor Technology
Topic: Serious FOCer (84V VESC 6 based controller)
Replies: 233
Views: 25896

Re: Serious FOCer (84V VESC 6 based controller)

I'm pretty sure it's due to the long gate drive traces passing from the control board to the power stage thought the pin headers. That's very likely, I also measured that the gate and output waveforms depend on the connector position and orientation, because there is a coupled feedback from the out...
by peters
Jan 10 2020 10:12am
Forum: Motor Technology
Topic: Serious FOCer (84V VESC 6 based controller)
Replies: 233
Views: 25896

Re: Serious FOCer (84V VESC 6 based controller)

Can you describe the issue in details? Do you think it's the power PCB layout or coupling between the stacked boards? I made a few similar boards for testing in the past few years and I know there are issues with the stacked structure but those are mostly manageable, although basically better to pre...
by peters
Jan 08 2020 2:25am
Forum: Motor Technology
Topic: Why more KV = more power, the Maximum Power Transfer Theorem
Replies: 51
Views: 3432

Re: Why more KV = more power, the Maximum Power Transfer Theorem

Yes for sure we don't want to stall a powerful motor with the battery voltage connected to it, but you can do that with small RC motors. But the theory of operation for only the motors (without controller) is the same. If you add the controller, that will limit the current to the allowed maximum by ...
by peters
Jan 07 2020 5:48pm
Forum: Motor Technology
Topic: Why more KV = more power, the Maximum Power Transfer Theorem
Replies: 51
Views: 3432

Re: Why more KV = more power, the Maximum Power Transfer Theorem

Nope, that’s still not clear. BEMF is not performing shaft work, and it’s not doing electrical work as it’s not driving current. Noooo, BEMF produces the real power with the current component that is in phase with BEMF. In the motor model the BEMF is a voltage source in series with the phase induct...
by peters
Jan 06 2020 6:01am
Forum: Motor Technology
Topic: Winding Question: does STAR make more torque than DELTA, even with adjusted phase current?
Replies: 17
Views: 1205

Re: Winding Question: does STAR make more torque than DELTA, even with adjusted phase current?

No, it doesn’t as the torque per amps drop off on saturation. The calculated current to drive the delta motor is based on that neither of the cores saturate as that stops the (semi) linear relationship between current and torque. I agree that torque per amps drops off, but the torque itself is the ...
by peters
Jan 06 2020 3:39am
Forum: Motor Technology
Topic: Winding Question: does STAR make more torque than DELTA, even with adjusted phase current?
Replies: 17
Views: 1205

Re: Winding Question: does STAR make more torque than DELTA, even with adjusted phase current?

I think it's not a saturation issue because a saturated winding produces more magnetic field and so should produce more torque than the same winding not in saturation regardless of the winding config (wye-delta), if the hall sensor vs. phase current position is adjusted (I mean the 30 degrees differ...
by peters
Dec 31 2019 3:53am
Forum: Motor Technology
Topic: Abyxx280, DIY Sensorless FOC ACIM motor controller.
Replies: 3
Views: 665

Re: Abyxx280, DIY Sensorless FOC ACIM motor controller.

Nice, good to see one more high power diy controller.
Can you tell more about the components? And which software do you use?
by peters
Dec 28 2019 1:08am
Forum: Motor Technology
Topic: PMSM Emrax 188 LV 30kW + Controller?
Replies: 4
Views: 354

Re: PMSM Emrax 188 LV 30kW + Controller?

I don't know this particular motor, but low inductance motors are normally driven from low battery voltage, because the current control needs reasonably low phase current ripple at the pwm frequency (consider U*dt=L*dI). I'd recommend to try it at the lowest controller supply voltage and the highest...
by peters
Nov 22 2019 12:55pm
Forum: EV Business World
Topic: Tesla Cybertruck
Replies: 48
Views: 4454

Re: Tesla Cybertruck

interesting design, gonna build one tomorrow morning 8)
by peters
Nov 12 2019 7:17am
Forum: E-Bike General Discussion
Topic: where can I find a steel front suspension fork?
Replies: 17
Views: 1468

Re: where can I find a steel front suspension fork?

Look for the dirt jump category, those are normally made for extra strength. Suntour Duro DJ-D 20QLC was a good and inexpensive choice with steel steerer and stanchions and 20mm thru-axle, but not sure you can still find one. There were variants for the usual 9mm axle, too.
by peters
Nov 01 2019 5:26am
Forum: Motor Technology
Topic: Sensorless From Standstill (SFS) explained
Replies: 24
Views: 2494

Re: Sensorless From Standstill (SFS) explained

Couldn't the LNAs be removed and the filter implemented in the firmware? At the expense of more noise I suppose, but is it a too strong restriction? Then the existing circuits would be compatible. In my case 10-15 ADC pins are quickly used up, because I measure all power supplies, 2 temperature sens...
by peters
Oct 30 2019 5:48am
Forum: Motor Technology
Topic: Sensorless From Standstill (SFS) explained
Replies: 24
Views: 2494

Re: Sensorless From Standstill (SFS) explained

This is magic.
I always thought the straightforward method would be to modulate the voltage amplitude (i.e. duty cycle) from PWM cycle to cycle and obtain the position from the changing currents, but your algorithm is very different.
by peters
Oct 22 2019 12:47am
Forum: EV Business World
Topic: Do you know this man ?
Replies: 14
Views: 1143

Re: Do you know this man ?

yeah, Chuck Norris.
by peters
Oct 10 2019 12:34am
Forum: Motor Technology
Topic: DIY Motor Dyno/load?
Replies: 24
Views: 1672

Re: DIY Motor Dyno/load?

Thecoco974: yeah, in this setup the direction is the same physically, but it is all about the 4 quadrants of the drives: https://en.wikipedia.org/wiki/Variable-frequency_drive#Drive_operation https://upload.wikimedia.org/wikipedia/en/8/83/Four_quadrant_motion_control_of_a_motor.jpg The driving motor...
by peters
Oct 09 2019 4:04am
Forum: Motor Technology
Topic: DIY Motor Dyno/load?
Replies: 24
Views: 1672

Re: DIY Motor Dyno/load?

You could use 2 identical motors and controllers, one in drive and the other in regen mode, or the second one also in drive mode with lower torque, that would rotate backwards, and powered from the same battery. Then most of the energy would be dumped back onto the battery, if the rpm is not close t...
by peters
Sep 23 2019 12:19am
Forum: Motor Technology
Topic: DIY 6FET Controller help
Replies: 299
Views: 34154

Re: DIY 6FET Controller help

added to my wishlist...
by peters
Aug 19 2019 6:27am
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 577
Views: 101574

Re: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15

Or, Lebowski, don't you want to write your algorithm in C and add to VESC or Axiom? One advantage is that the FPU in the ST uC-s makes the calculations easier. Another possible advantage is the nonlinear BEMF (flux) observer in the VESC, that is very effective. I didn't dig much into the VESC code, ...
by peters
Aug 13 2019 8:14am
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 142
Views: 20473

Re: BESC - beefed up VESC motor controller for high power ebikes

Thanks HighHopes but I know the tricks of these measurements. Only a small portion of the amplitude came from the limited common mode rejection of the probe and another small portion was the coupled inductive noise from di/dt.
by peters
Aug 11 2019 12:04pm
Forum: E-Bike General Discussion
Topic: Hub motor industry dying?
Replies: 270
Views: 14648

Re: Hub motor industry dying?

I think the current hub motors are far from the max. feasible torque/mass ratio, there are chances for improvement and optimization. Large diameter hollow axle, design for uniform strength with FEA, etc. The manufacturers should work on it, but maybe they are not interested in.
by peters
Aug 11 2019 11:32am
Forum: E-Bike General Discussion
Topic: Help me develop the perfect throttle
Replies: 75
Views: 5131

Re: Help me develop the perfect throttle

Sliding grip? That would turn (slide around) after a reasonably high force to prevent breaking the internals of the throttle. I'm thinking of this since mine was broken.
by peters
Aug 07 2019 10:38am
Forum: Motor Technology
Topic: Serious FOCer (84V VESC 6 based controller)
Replies: 233
Views: 25896

Re: Serious FOCer (84V VESC 6 based controller)

That's also interesting, but I just looked at the datasheet of DRV8353RS and interested in how you apply it. It requires max. 75V on the VM input, but your battery max is 84V, has an internal DC/DC converter that you probably use to supply the uC, but there is no inductor on your 3D view. Things lik...
by peters
Aug 07 2019 7:36am
Forum: Motor Technology
Topic: Serious FOCer (84V VESC 6 based controller)
Replies: 233
Views: 25896

Re: Serious FOCer (84V VESC 6 based controller)

Will you publish your schematics? I'm wondering how you connect your gate driver and power supplies.
by peters
Aug 02 2019 1:57am
Forum: Motor Technology
Topic: MOSFET gate driver ringing causes
Replies: 5
Views: 694

Re: MOSFET gate driver ringing causes

yes, additional capacitors on the DC bus rarely help. The PCB must originally be designed to accommodate all caps with low inductance. My observation was that the new low frequency (660kHz) is the oscillation between the big DC bus cap and the new 1uF, and the high freq (10MHz) is between the 1uF an...