Search found 293 matches

by pf26
12 Feb 2018, 17:34
Forum: General
Topic: Strange motor behavior
Replies: 4
Views: 420

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: 356

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: 420

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: 1794

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: 403

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: 245

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: 2656

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: 2104

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: 274

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...
by pf26
29 Dec 2017, 09:00
Forum: Hardware Problems
Topic: VESC DRV8302 Problems MOSFET Swapping Considerations to all!
Replies: 14
Views: 2682

Re: VESC DRV8302 Problems MOSFET Swapping Considerations to all!

Unsoldering the FETs with hot air should be quite easy if you had a hot air station. I think you better leave the FETs in place and add a thick copper bar to the drain of the 3 top FETs, in order to connect them thermally with your aluminum case (it will connect these electrically too, unless you ha...

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