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by pf26
15 Jul 2018, 16:06
Forum: Related Hardware
Topic: Battery overvoltage protection - dump load
Replies: 8
Views: 103

Re: Battery overvoltage protection - dumb load

Did you have a look at this one: http://vedder.se/forums/viewtopic.php?f=15&t=586 ? (dump, not dumb..)
by pf26
12 Jul 2018, 14:38
Forum: Related Hardware
Topic: Battery overvoltage protection - dump load
Replies: 8
Views: 103

Re: Battery overvoltage protection - dumb load

I doubt you scheme will work. When the dump load is switched on, the internal resistance of the battery will cause the main voltage to drop, and depending upon the hysteresis of your comparator, will switch off the load or not. Anyway, you need some capacitance somewhere to have your dump load switc...
by pf26
21 Jun 2018, 16:49
Forum: Custom Applications
Topic: Dual motor setup over CAN with UART
Replies: 2
Views: 135

Re: Dual motor setup over CAN with UART

To send commands to the master VESC (ID=1), I think you better send the command directly, and not use the Forward command : i.e. remove these 2 lines when ID=1 payload[index++] = COMM_FORWARD_CAN ; payload[index++] = address ; I checked your CRC calculation. and it seems correct. Maybe you should ma...
by pf26
14 Jun 2018, 09:25
Forum: General
Topic: Freezing during PID Positional Control (with encoder)
Replies: 2
Views: 180

Re: Freezing during PID Positional Control (with encoder)

Possibly the motor startup currents interfere with your hardware. You could try to improve your routing (wiring away from power cables), or lower the motor max current, or use separate power sources for VESC and your hardware (if not already the case). You should be able to transmit position referen...
by pf26
04 Jun 2018, 09:04
Forum: FOC
Topic: FOC on eBike - cuts in acceleration
Replies: 5
Views: 528

Re: FOC on eBike - cuts in acceleration

You could try to reduce the FOC current controller parameters (Ki and Kp), say by 20%, and see if it helps.
It is also possible to adjust manually the R and L of the motor, but I do not know in which direction to go.
by pf26
02 Jun 2018, 06:03
Forum: FOC
Topic: FOC on eBike - cuts in acceleration
Replies: 5
Views: 528

Re: FOC on eBike - cuts in acceleration

In BLDCTOOLS, motor configuration/Motor/Current limits, you could set a higher "Absolute Max" parameter. This will reduce your "ABS_OVER_CURR" faults, at the expense of a greater risk to blow your VESC. Reason is the current control is not perfect, and setting too little margin b...
by pf26
01 Jun 2018, 08:26
Forum: General
Topic: Vesc constant speed control in code?
Replies: 1
Views: 168

Re: Vesc constant speed control in code?

You don't need to change the code. You can add a little application to the firmware. You can create a file like this: // Settings #define SpeedReference 3000 #include "ch.h" // ChibiOS #include "hal.h" // ChibiOS HAL #include "mc_interface.h" // Motor control functions ...
by pf26
25 May 2018, 17:03
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 7
Views: 353

Re: FOC vs BLDC Torque Question

For a given RPM, the motor (mechanical power) output is determined by the load, namely the propeller, and they keep the same one during all the experiment.
You can check the powers seem to vary approx as a cube law of RPM, which makes sense.
by pf26
25 May 2018, 12:43
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 7
Views: 353

Re: FOC vs BLDC Torque Question

If you assume the VESC efficiency is 100%, and the motor efficiency does not vary much between BLDC and FOC, then you get the same torque when running at a certain speed with a given power input from the battery. But in your case, with high coil resistance and large input current, the motor Joule lo...
by pf26
29 Apr 2018, 18:51
Forum: FOC
Topic: FOC braking?
Replies: 21
Views: 6257

Re: FOC braking?

I imagine you use "brake mode" and set a brake current using BLDCTools. Did you try to use "current mode", and set a negative current ? I suspect the issue is related to this in mcpwm_foc.c : // When the filtered duty cycle in sensorless mode becomes low in brake mode, the // obs...

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