Search found 940 matches

by rew
11 Feb 2018, 15:47
Forum: FOC
Topic: VESC FOC for a flywheel application....
Replies: 14
Views: 1950

Re: VESC FOC for a flywheel application....

Still I've been thinking lately.... Those TRENT1000 motors have 3m diameter turbine-disks running at 14k RPM.....
by rew
11 Feb 2018, 15:40
Forum: General
Topic: current measurement with 2 shunts?
Replies: 3
Views: 501

Re: current measurement with 2 shunts?

I have a clamp ammeter. It is fun to test the new hires here: With the motor current set at say 10A, you put the clamp on one wire. 10A. Next wire: 10A. Now those two wires together... How much do you expect? The answer is: Again 10A! The two sines of 10A RMS add up to a third sine of 10A RMS. And t...
by rew
11 Feb 2018, 15:20
Forum: General
Topic: Parallel FETs
Replies: 3
Views: 399

Re: Parallel FETs

Even with a half-h-bridge-power-board with the fet-driver on the board, a guy claiming to know about power electronics said: "your fet driver is too far from the FET". And that is with me doing my very best to get it as close as possible.... So simply taking an existing VESC and connecting...
by rew
28 Jan 2018, 11:47
Forum: FOC
Topic: VESC FOC for a flywheel application....
Replies: 14
Views: 1950

Re: VESC FOC for a flywheel application....

rew, that's interesting: can you elaborate a bit on that? I.e. what has been fixed in newer firmware that enables higher ERPM? My belief was that it was the three shunts of VESC6 that enabled it to run at higher ERPM, but my understanding of this is fuzzy at best. :oops: I just remember Benjamin sa...
by rew
28 Jan 2018, 11:44
Forum: General
Topic: raspberry pi electric skateboard
Replies: 3
Views: 501

Re: raspberry pi electric skateboard

From your description I get the impression that you are setting the dutycycle from some sort of throttle. Many people have found out before you that this does not result in a comfortable ride.

The idea is that the throttle controls the current through the motor and therefore the acceleration.
by rew
22 Jan 2018, 09:43
Forum: FOC
Topic: VESC FOC for a flywheel application....
Replies: 14
Views: 1950

Re: VESC FOC for a flywheel application....

You can even run the latest firmware on older hardware to increase the achievable ERPM limit. (It's a software issue, so a software fix will fix even old hardware).
by rew
13 Jan 2018, 11:17
Forum: FOC
Topic: DRV8302 faults with FOC
Replies: 27
Views: 13213

Re: DRV8302 faults with FOC

The "low ESR" is a secondary property of the capacitor. There WAS an issue with a capacitor being "marginal" on it's primary property: capacitance. When that happens, you simply need the bigger (in capacitance) capacitor!
by rew
06 Jan 2018, 18:13
Forum: Hardware Problems
Topic: DRV fault code on FOC detection
Replies: 9
Views: 2200

Re: DRV fault code on FOC detection

That pulldown resistor is connected like that due to layout issues. Where it is connected now is connected to the "normal" place through one or two 0.001 ohm resistors. So the resistor still does its work, but at 0.002 ohms more resistance. With the DRV, you can DISABLE the FET outputs. In...
by rew
06 Jan 2018, 18:04
Forum: FOC
Topic: Technological choice alternatives
Replies: 1
Views: 362

Re: Technological choice alternatives

- As you don't use the built in current sense from the DRV8302, do you think it is a mistake to deal with regular mosfet driver ? Yes, my variant of the VESC uses just normal LM5109 or IR2xxx FET drivers. The VESC started out with "guidelines" from TI which said: you need only two current...
by rew
23 Dec 2017, 23:52
Forum: Custom Applications
Topic: VESC4X
Replies: 3
Views: 529

Re: VESC4X

The STM32F412 does not have the 3 ADC modules that the VESC uses.

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