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by pf26
18 Mar 2018, 19:22
Forum: General
Topic: Low speed high torque
Replies: 3
Views: 739

Re: Low speed high torque

Did you try to play with the Speed Tracker Kp and Ki parameters in BLDC tools, so as to improve the motor speed estimation, and in turn, the speed control ? In FOC mode, the speed estimation is made by the pll_run function in mcpwm_foc.c If this doesn't work I fear you need to add some sort of index...
by pf26
12 Feb 2018, 17:34
Forum: General
Topic: Strange motor behavior
Replies: 4
Views: 595

Re: Strange motor behavior

Why not use FOC + current_control ?
by pf26
10 Feb 2018, 16:17
Forum: General
Topic: Parallel FETs
Replies: 3
Views: 503

Re: Parallel FETs

Driving FET gates requires a lot of current spikes to be quickly charged/discharged to switch. The DRV is used near its max gate driving capacity. Also be aware that the pcb layout of the power section impacts a lot the performances (as you can see in the thread and many iterations of the minivesc f...
by pf26
10 Feb 2018, 15:56
Forum: General
Topic: Strange motor behavior
Replies: 4
Views: 595

Re: Strange motor behavior

I assume you use FOC (I could not convert your .7z file now). You should open the mcpwm_foc.c and look how "duty_cycle" mode is implemented. I think you better use current control mode, and send current (ie torque) requests to the VESC. And better still would be to implement your control i...
by pf26
08 Feb 2018, 15:50
Forum: FOC
Topic: VESC FOC for a flywheel application....
Replies: 14
Views: 2280

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

@seandepagnier: 100kERPM is not 100kRPM. For large pole pair numbers, extreme ERPM are easily achieved.
by pf26
08 Feb 2018, 15:46
Forum: General
Topic: Calculating motor heating?
Replies: 4
Views: 592

Re: Calculating motor heating?

I think your calculation is correct: Rxi² = 0.1 * 20² = 40W joule losses. As for the iron/friction losses, you can estimate them with a constant drag torque of 1-2% of the max motor torque, depending on motor quality obviously. You could also measure your motor no-load power consumption vs RPM, and ...
by pf26
14 Jan 2018, 09:52
Forum: General
Topic: Disabling all "ramping features"
Replies: 1
Views: 327

Re: Disabling all "ramping features"

Possibly you could review your chain by: Arduino DUE => CAN => VESC => Motor with Encoder (also used as Position Sensor if you implement multiturn detection in a VESC custom application) => Apparatus => extra position Sensor (if needed) => Feedback to Arduino Then you could use the VESC internal pos...
by pf26
13 Jan 2018, 16:16
Forum: Feature Requests
Topic: Out of the box support for AS5048
Replies: 9
Views: 3066

Re: Out of the box support for AS5048

I think the AS5047 support uses a software SPI, in encoder.c : The MISO ReadPad is done after the SCK SetPad, when it probably should only occur after the SCK ClearPad static void spi_transfer(uint16_t *in_buf, const uint16_t *out_buf, int length) { for (int i = 0;i < length;i++) { uint16_t send = o...
by pf26
31 Dec 2017, 10:45
Forum: Custom Applications
Topic: CAN-BUS Forwarding
Replies: 5
Views: 2456

Re: CAN-BUS Forwarding

In datatypes.h, you can see the enumaration of all communication commands, and COMM_FORWARD_CAN is the 33rd in the list, hence the constant COMM_FORWARD_CAN=33.
by pf26
29 Dec 2017, 19:19
Forum: Custom Applications
Topic: Brake at special position? is this possible ?
Replies: 1
Views: 397

Re: Brake at special position? is this possible ?

If you constantly send the same reference position, the motor will always try to move to that position. If you turn the motor axis away from this position, it will give a torque (depending on the maximum motor current you set) so as to return to this position. I think you better use rotary encoder w...

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