## Search found 255 matches

30 Aug 2018, 17:27
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 9
Views: 19412

### Re: FOC vs BLDC Torque Question

This papers shows how FOC performs better than BLDC with some numbers (a bit surprinsigly high to me) http://www.imavs.org/papers/2016/167_IMAV2016_Proceedings.pdf @pf26 I sought to prove or disprove mathematically whether FOC is in fact more efficient than BLDC... here are my findings: -----------...
28 Aug 2018, 16:03
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 9
Views: 19412

### Re: FOC vs BLDC Torque Question

I think I found the formula for calculating FOC torque from RMS motor current at the following site: https://www.motioncontroltips.com/what-is-sinusoidal-commutation-for-dc-motors/ T = 1.5 * Kt * M where M is the RMS motor current per phase command and T is the torque in newton meters. So I then wan...
28 May 2018, 03:50
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 9
Views: 19412

### Re: FOC vs BLDC Torque Question

I seek to calculate for a given BLDC/Block Commutation motor current limit value at full throttle, what peak motor current limit value in FOC mode (3 phase sinusoidal) at full throttle gives identical electrical power consumption, efficiency, torque, losses and mechanical power during acceleration. ...
27 May 2018, 01:11
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 110
Views: 52995

### Re: "Peak Efficiency" Control Mode?

This update calculates battery current, motor current and electrical wattage targets for control loop implementation. Please note there are presently 2 throttle variations of efficiency control - watt control throttle & motor current control throttle (both variations updated here). In BLDC / blo...
25 May 2018, 22:29
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 9
Views: 19412

### Re: FOC vs BLDC Torque Question

for example this chart shows bldc, 8v battery, 100kv, 0.1ohm, 100mm tire, 0.104:1 gearing & accelerating at 50% duty control vs 60% duty control. according to these calculations, I notice while accelerating through 222.33rpm (labeled 25mph ground speed) when i decrease duty control to 50% duty c...
25 May 2018, 17:27
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 9
Views: 19412

### Re: FOC vs BLDC Torque Question

if i have a graph that shows 2 accelerating props (both bldc, one at constant 50% duty control & one at 60% duty control), and the 50% duty prop is accelerating more slowly than the 60% duty prop, wouldn’t the comparison graph show the 50% prop having improved efficiency and lower power consumpt...
25 May 2018, 15:37
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 9
Views: 19412

### Re: FOC vs BLDC Torque Question

^in this paper there are 2 graphs showing power consumption and efficiency of a motor with FOC vs BLDC... in the graphs, foc is shown to have reduced power input and improved efficiency at all rpms... but what isn’t shown is a graph of the mechanical power output of the motor with FOC vs BLDC... If ...
25 May 2018, 01:38
Forum: General
Topic: FOC vs BLDC Torque Question
Replies: 9
Views: 19412

### FOC vs BLDC Torque Question

i have a question about FOC (sinusoidal commutation) vs BLDC (block/trapezoidal commutation). suppose I have a 100kv 0.1ohm lead-to-lead BLDC motor and an 8v battery. according to my calculations the KM size constant for this motor is 0.3019nm/sqrt(w) KT = 60/(2 * pi * 100kv) = 0.0954929658551372014...
24 May 2018, 23:21
Forum: General
Topic: Sensorless tach with brushed motors
Replies: 2
Views: 2231

### Re: Sensorless tach with brushed motors

if you can find a way to observe the back emf voltage then i believe instantaneous back emf voltage * measured kv of the motor should give rpm
08 May 2018, 16:44
Forum: General
Topic: DIFFERENTS CURRENTS
Replies: 3
Views: 3186

### Re: DIFFERENTS CURRENTS

@andre_denzel here is a chart showing the predicted performance of an electric skateboard in bldc mode with 50a motor limit and 50a battery limit software user settings... take a look at the blue and black lines, top left chart (motor amps and battery amps) and the red line, bottom right chart (batt...