New answers tagged brushless-dc-motor
1
Currently, modern technology pushes towards BLDC
That is not exactly true. Reluctance-permanent magnet hybrids are also and perhaps reluctance-only are also being considered.
What are the pro/cons of one compared to the other?
Advantages in efficiency, reliability, physical size, and performance are under consideration. Each of the advantages can be ...
4
You are using a standard 35µm 4-layer stackup, which is fine. Signal/power/power/signal is also quite common. Digital and analog plane on the same layer is fine even without lot of separation.
Now, for the questions: the control board is often separate (plugged in vertical in many design) to better isolate the controller from the switching noise. Also with ...
2
Asynchronous machines (induction motors) are used because of their simplicity and robustness. As soon you add additional circuitry, that advantage diminishes. In difference to a synchronous machine (brushless DC motor),
the torque of an asynchronous machine is a function of slip. For a given motor, demanding more torque means having more slip and that means ...
0
I think that you are wrong to position energized phases after bemf falling. You should energize windings first of descending phase of bem. Provably the detection circuit dont work well , filter capacitance too big and therefore delay
1
Besides the custom controls and the higher rating of the VESC are
there any other differences?
Isn't that enough? Considering the sheer amount of capabilities hidden behind "custom controls" and more than 12 times current available (some VESC controllers go up to 300A continuous).
VESC provides multitude of control protocols, like CAN, USB, UAVCAN ...
3
The E-bike controller appears to have a PWM AC output for closed-loop control of a brushless permanent magnet motor.
The VESC looks like it may have a similar capability.
Looking at just the online sales information, it is difficult to evaluate what is being offered with either product.
The E-bike controller is the type that is suitable for the linked motors,...
0
In the comments you specify a top speed of 20 km/h, all-up weight of 300 kg and ability to climb a 30° slope. I put your figures (plus some estimates for drag and rolling resistance) into the online calculator at Built-For-Fun EVs, and it returned the following:-
Drive train output power required for 20 km/h on flat ground: 1913 watts.
Output power required ...
1
Measure the DC resistance, R, of one of your motors.
Calculate the starting current using \$ I = \frac V R \$ where V is the supply voltage.
Your power supply current rating should be ≥ \$In\$ where \$I\$ is the calculated current above and \$n\$ is the maximum number of motors to be run at any time.
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This is a nontrivial problem. There are a large number of metrics to evaluate across, and to provide a generic answer to this question is impossible. However, there are some tricks to teasing out motor parameters from the wide variety of available brushless DC motors on the market with sparse specifications.
A lower RPM per V motor has a higher torque ...
4
As a motor designer, I am going to give you a dimensional approach to selecting a motor. Torque is proportional to the rotor radius squared. Torque is linearly proportional to length.
\begin{equation}
\tau \propto r^2l
\end{equation}
What does this mean??
It means that you will want a motor that looks more like a pancake than a hotdog. I suggest you look at ...
0
The simple way is to figure out the maximum RPM you need to hit top speed. Then divide by battery voltage. That is the Kv you need (approximately...). Kv * Vbat gives you a rough estimate of how fast your motor will spin.
Then figure out the maximum torque you need for worst case hill-climbing and vehicle loading. Convert torque to Nm. Convert max speed from ...
1
There is a motor efficiency factor and a transmission (gearbox) efficiency factor. You choose the motor and gearbox, so that fulfills the constraints about torque/max. speed and efficiency. There are also many other parameters to consider:
cooling capability
mechanical forces on motor/gearbox. The transmission of type belt/pulley exhibits large radial force ...
0
RPM per volt is a specification that describes the motor in DC commutator motor terms. A motor and controller combination that is designed to emulate DC commutator performance will probably not provide what you need. A system like that will provide constant torque capability over the speed range.
With an engine-driven vehicle, the transmission gear change ...
0
Black wire on the motor to GND on raspi. Pay attention to the length of the black wire on the motor - if you extend it, then voltage drop might be an issue. In which case it may cause the raspi to fail. A raspi isn’t intended to control things in the real world without protection.
1
Torque = current and 150A isn't enough, so...
Gear down to the prop.
Sanity check : a 5HP Seagull Silver Century drives its 11 inch prop at about 1000rpm, which you would reach with only 3V on your motor direct drive. If you're trying to run this thing at 12V that's about 4000rpm, and power required varies as the cube of speed (torque as the square of speed) ...
0
Well,
Either your ESC is not doing it's job well and Iq is not well controlled, either your need more current.
BLDC are rather simple beast, in your case you should be interested in back EMF and torque constant (the two are related with a sqrt(3) factor when in V/s and Nm/A).
The torque constant gives you the relation between torque and current, it's value ...
3
If you can't change anything in the drive, you can't: BLDC motor driver are basically 3-phase inverters, that is the output is AC voltage.
If you can reprogram the MCU in the drive, you could theoretically use only two legs and make some kind of an H-bridge that would be suited for a brushed motor. However, I think this would require a lot of works, and the ...
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I don't need this for my switching scheme, am I right?
Correct. You only need dead time if you are switching the high and low sides of a phase terminal alternately, eg. when doing synchronous PWM or 'active freewheeling'.
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