Search found 940 matches

by rew
23 Dec 2017, 23:48
Forum: Custom Applications
Topic: VESC for VR treadmill
Replies: 4
Views: 669

Re: VESC for VR treadmill

You do NOT want to tell both motors to do the same speed. Any minor error will cause the motors to fight each other. With PWM control, you get a slightly better situation. The effective resistance of the motors will allow them to adjust a bit to small errors. Still it is quite possible that one moto...
by rew
23 Dec 2017, 23:42
Forum: General
Topic: Improve cooling
Replies: 10
Views: 2252

Re: Improve cooling

Looks nice, but read my posting from 15 months ago: You are not effectively cooling the mosfets. any heat generated inside the mosfet has to travel through the 10x higher thermal resistance to the outside of the FET.
by rew
05 Dec 2017, 21:46
Forum: General
Topic: Failsafe shutdown of VESC
Replies: 4
Views: 726

Re: Failsafe shutdown of VESC

I asked TI about providing the PVDD externally. They answered! The response: DO NOT DO THAT! That might be (and probably is) just CYA policy, but that's the official word.... (I use a DCDC converter in an application. The datasheet says: "min load: 10% of max load". In my application the l...
by rew
02 Dec 2017, 20:30
Forum: VESC Projects
Topic: VESC in homemade lathe/drill press
Replies: 11
Views: 1654

Re: VESC in homemade lathe/drill press

Yes. The torque constant is actually the same as the motor constant Kv. Or depending on the units the inverse (*). 245Kv is 245 RPM / Volt = 245 (RPM/V) / 60(sec/min) * 2*pi (rad/rotation) = 25 rad/sec/V That means the torque constant is 1 over that, or 0.04 Nm/a. So for 40A you get: torque = 0.04 N...
by rew
02 Dec 2017, 19:49
Forum: General
Topic: Failsafe shutdown of VESC
Replies: 4
Views: 726

Re: Failsafe shutdown of VESC

I have had my lab powersupply backfed from braking the motor. Once with the powersupply at its max and a few times less agressive with some margin on the powersupply. But yes, the VESC will remain powered even if it cannot drive the fets as long as the motor turns....
by rew
02 Dec 2017, 19:26
Forum: General
Topic: 180 degree commutation with sensors vs standard 120
Replies: 13
Views: 1849

Re: 180 degree commutation with sensors vs standard 120

No, From what I read above, the "180 deg commutation" is simply BLDC but with an extra motor coil powered up. (Y or Delta does not matter). But if we think about what we want to achieve.... We have a permanent magnet in an electromagnetic field. We want to set up that magnetic field that h...
by rew
25 Nov 2017, 11:38
Forum: FOC
Topic: Formulas of Ki, Kp, observer gain
Replies: 3
Views: 652

Re: Formulas of Ki, Kp, observer gain

Nathan wrote:have very high inductivity - 12000mH.

That is VERY high. So if we apply 12V, after about a second the current will have risen to 1A. So more than about 20 - 30 RPM is imposible with this motor. Are you sure?
by rew
20 Nov 2017, 09:15
Forum: General
Topic: Error: read version failed when trying to use OpenOCD 0.7.0 with STM32F407 Discovery Board As Programmer
Replies: 5
Views: 2259

Re: Error: read version failed when trying to use OpenOCD 0.7.0 with STM32F407 Discovery Board As Programmer

The discovery board is a reliable programmer. First try flashing the BLDC firmware into the CPU on the discovery board, then try removing the jumpers and making theconnection to the VESC. So this way you know for sure if it is software you're having trouble with or hardware.
by rew
11 Nov 2017, 09:43
Forum: FOC
Topic: FOC poor efficiency at high speed
Replies: 20
Views: 3621

Re: FOC poor efficiency at high speed

I messed with the switching speed. No real effect. Still craps out around 50% duty cycle. Is there any way to start in FOC and switch to BLDC at a certain RPM?? With the current firmware: Definitively no. Switching from one side to the other in the current setup means that the "other" str...
by rew
11 Nov 2017, 09:38
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 110
Views: 15519

Re: "Peak Efficiency" Control Mode?

[remember in the scenario the customer states his requirements include at least 30mph on flat ground, and greatest range while repeatedly accelerating full throttle in start and stop traffic.] So, your rider is allowed to press full-throttle, but the motor controller will, in the interest of effici...

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