Questions tagged [brushless-dc-motor]

A brushless DC electric motor is a DC motor type that uses an electronic inverter/switching circuit to energize the motor coils in a sequence (based on the detected rotor position) in order to rotate the motor.

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241 views

Relationship between brushless coil inductance and back EMF as a function of phase angle

In general, does the inductance across the coils of a brushless motor have the same waveform as the back EMF? That is, if back EMF is sinusoidal, should I expect the inductance to be sinusoidal [with ...
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224 views

BEMF polarity is backwards

Please take a look at this waveform of a 3 phase, BLDC motor: Check out that rising and THEN falling slope...Pretty nice. Now, take a look at what I'm getting on my motors sensorless resistor ...
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1answer
316 views

FOC current control autotuning PI Controller for BLDC Motors

I try to understand, how the guys from odrive tuned the current control PI parameters for Field Oriented Control: https://github.com/madcowswe/ODrive/blob/master/Firmware/MotorControl/low_level.c In ...
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122 views

High side current sensing in BLDC motor?

I want to measure DC current flow through the 48 V battery in bldc motor (through Inverter circuit). Are INA 282, INA 169 work properly or not? Since my battery motor specification is 48 V, 5 Amp, 250 ...
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78 views

Using a 670Kv outrunner motor, how can I calculate a way to get variable low speed and high torque?

I have an E-flite Power 46, 670Kv outrunner motor (Kv is the shorthand for RPM/volts, it has 3.9A idle current, 40A maximum continuous current, 14.4-19.2 voltage range, 925 watt maximum) but I wish to ...
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3answers
441 views

Can an Induction motor be called a BLDC motor if operated from a DC supply?

A BLDC motor is a Permanent Magnet Synchronous Motor which is powered by a DC supply via an inverter stage. Since the motor is externally commutated by the inverter and the supply is DC, it is called "...
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1answer
419 views

Is there possibility to “short” and lock a BLDC motor as on the DC brush motor

As we know, you can mechanically lock a DC brush motor by short the two terminals with relative strength. Now, in my design I wanted to use BLDC for reduced noise, but can I do something similar for ...
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745 views

What is the main reason for using speed feedback in a motor positioning control system?

This question is not to solve a particular problem but rather one of principle to understand the main reason a designer would want to include speed feedback in a motor controlled positioning system. ...
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1answer
332 views

Floppy / Brushless DC motor speed regulation [closed]

I have a non working TEAC FD-235f 161-U, which is a rather rare (nowadays) 3-1/2" Amiga floppy drive. A cap had leaked over the PCB and eaten away at the traces. I jumper wired the broken traces and ...
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116 views

SPACE VECTOR MODULATION(SVM) for BLDC motor

I want to run a 4 pole bldc motor(12V) using SVM in open loop. microcontroller: Infineon IDE: Keil Microvision. I have successfully generated the Space vector which starts rotating as shown in the ...
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2answers
164 views

Designing from low-voltage 3-phase motor driver for more powerfull BLDC motor

I am starting to work on undergraduate project to build electric skateboard. Main thing I will foucus on, will be ESC (electric speed controler) made for a motor 190KV (motor spec.). I got micro-...
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136 views

Overcoming cogging/ripple torque in gimbal motor

So I'm trying to figure out how to spin a camera on a brushless gimbal motor. I am feeding each of the terminals a sinusoidal pwm signal from a via 3 half bridges on the SN754410. Each of the pwm ...
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1answer
111 views

controling bldc motor with atmega32 [closed]

is it possible to control the speed of a bldc motor using a direct connection to ATMEGA32 microcontroller? Or there should be an interface since motors need more voltages than the microcontroller (...
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2answers
88 views

Wire gauge on Drones different?

How is it a 12 volt 40 amp wire in a car has to be approximately 16mm thick but a drone can use 3.5mm thick cable for 12 volt 120 amps. What is the difference? They both have the same amount of power?...
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1answer
138 views

What are the functions of the diodes in this BLDC controller circuit?

I'm trying to understand the function of the diodes in this snippet of an automotive BLDC controller. I believe that D102 is for over-voltage protection, and reverse polarity protection. Also, I ...
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1answer
173 views

OpAmp for FOC current sensing on a BLDC/PMSM

How critical is this pull-up resistor to Vdd for current sensing in a Field Oriented Control of a BLDC or PMSM? Right now, I don't have that pull up...I'm running the shunt resistor voltage straight ...
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1answer
766 views

Output of Brushless ESC for controlling Brushless Motor

Suppose, I have 40A ESC and Brushless Motor with max current capacity of 30A. I am using Receiver for controlling Motor speed and Arduino as controller. Receiver sends 1ms to 2ms pulse every 20ms. ...
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1answer
326 views

Bldc hub motor starting torque

am designing a BLDC hub motor (48V-500W-15A max) I have designed a three phase inverter and the motor run normally with smooth rotation and as the motor start running and I apply the load the motor ...
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3answers
7k views

Finding number of pole pairs in a BLDC motor

I have a 3phase CDROM BLDC motor for which I don't have any datasheet. How can I find out the number of pole pair in the motor? Hint:-With a magnet, I could check that there are some N and S poles in ...
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1answer
117 views

What's the best starting point for rotor angle estimation for FOC?

I'm driving a BLDC motor with FOC. Right now, I have Space Vector modulation working, where I can give it a magnitude and an angle, and the algorithm will drop the right values into three PWM ...
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294 views

What happens to inverter if running motor controller without load (motor)?

Consider running a 3 phase BLDC motor controller having 20KW inverter fed by 100V whence designed for high amperage. What happens if we turn it on and start gradually increasing duty cycle of the ...
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3answers
626 views

Does the continuous power-to-weight ratio of electric motors decrease with size?

Background: According to the DEP overview section of this NASA paper, aviation companies are interested in distributed electric propulsion (DEP) because the scale-agnostic power-to-weight ratio of ...
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1answer
1k views

How does a hobby ESC drive a BLDC motor? [closed]

Background: I'm an aerospace engineer modeling the electrical systems of a standard quadcopter. I came across a lot of technically-inadequate or incorrect material while researching the humble yet ...
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2answers
1k views

Drive voltage vs phase voltage of a BLDC motor

Background This video on using an oscilloscope to view the line-to-line phase voltages of BLDC motors demonstrates the "virtual" ground necessary for such measurements. I understand this idea: you ...
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1answer
539 views

Total current used by a brushless DC motor

Is it correct to say that 'the current' drawn by a BLDC motor is the same as the current from any single phase at a given time (assuming they are all balanced/equal in magnitude)? I came across this ...
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3answers
2k views

What does changing the throttle to a BLDC ESC actually do?

Background: I understand how the standard 50 Hz PWM protocol for hobby electronics works: varying the on-time from about 0.5 ms to 2.5 ms will throttle an actuator from roughly 0% to 100% thanks to ...
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1answer
74 views

Counting slow to fast in a microcontroller.(Ramp)

I want to make an increment(++) to a variable initially slowly then speed up linearly. For example, using a timer interrupt(every 1 sec) in increase the variable x by 1.so at first variable get ...
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58 views

What to do with PI feedback value

I've been studying and trying to implement a PI feedback controller for a BLDC. Right now, just to unit test the code for the PI controller, I'm driving two phases with a PWM signal on a MOSFET ...
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2answers
484 views

What determines the continous ratings of electric motors?

I've seen variations of this torque-speed curve for brushless DC motor performance, and I'm curious what criteria determine the rated torque and speed of permanent magnet DC motors in general. Does ...
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3answers
445 views

PWM switching in BLDC motors: ratio between switching losses versus conductive

There were some good posts regarding choosing the PWM switching frequencies considering the needs of the motor control. Here I am focusing rather on understanding of how to decrease losses in the ...
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3answers
201 views

Need help regarding power source for a 60V BLDC motor

I'm mostly new to electronics and stack exchange sites. I'm developing a small, lightweight, real life car (2 seater) for my school project. It is going to be run by a motor. I've chosen a brushless ...
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1answer
468 views

FOC Motor Control Algorithm - ADC sampling

I'm working on implementing the FOC motor control algorithm on an STM32F411 microcontroller. My question is about when you need to sample the phase currents in relation to your PWM pulses. If you turn ...
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2answers
270 views

Rectifiers in parallel - mosfet

I see the question has been asked a few times about using rectifiers in parallel to get a higher current rating and this is not advisable however I wanted to ask how this would apply to a active ...
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2answers
2k views

Speed and Torque control of a BLDC

First off, I have very little knowledge in electrical engineering and my last official contact with the subject was when I was in high school so go easy on me. I am trying to understand if it's ...
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1answer
1k views

Measure time between two GPIO events in STM32 [duplicate]

I want to measure the RPM of a motor that I am controlling using a STM32 and some driver chip.. My understanding is that I have to measure the time between 2 hall signal and calculate the speed (RPM). ...
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1answer
261 views

PWM commutation strategy for Sensorless BLDC

For brushless DC motor, we use 6 step commutation. For voltage control, in each phase, PWM is used to drive the Bridge MOSFETs. And for the sensorless algorithm, Back EMF of non-energised phase is ...
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1answer
636 views

problem with BLDC motor drive using PWM

We are trying to speed control a BLDC 48V 500W hub motor using hall sensors we are using IRF540N mosfets with IR2112 gate drivers and arduino as MCU we implemented the 3 phase inverter and in testing ...
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3answers
65 views

brushless for outboard of a 4 meter boat

SK3 - 6364-190kv Brushless Outrunner Motor ... this motor has a nominal voltage of 37 V with a maximum current of 65 A, Can I supply this motor with a voltage of 24 V, with a current of 30 A? how much ...
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3answers
3k views

Electric BLDC motor voltage and power limit factors

Preliminary: I know basic model of DC motor which depends of two electric parameters such as voltage/rpm and current/torque. There are two models electrical - resistance, back EMF, and optional ...
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3answers
1k views

Dynamic Braking MOSFET Control Circuit [duplicate]

I am dealing with a regenerative power situation with BLDC motor and servo drive controller.The power supply is 48V regulated DC but during deceleration due to regeneration, the voltage at drive ...
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1answer
101 views

BLDC Commutation and output states of half bridges

I am trying to run a BLDC motor using TI DRV832. In the datasheet, there is the following truth-table, where I do not know what are GLx, GHx and SHx. Also, what does Hi-Z do? I want to control the ...
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2answers
403 views

Permanent magnet in ac motor

Is Magnet in pmac motor degrade while they are in use because in tesla model 3 they uses pmac motor so we have to replace magnet frequently ?
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4answers
1k views

How any one achieve sinusoidal back emf in PMSM and Trapezoidal back EMF in BLDC ? What is the winding differences?

How any one can achieve sinusoidal back emf and trapezoidal back emf in the motor. What is the winding differences in those motors. I have take an In-wheel BLDC exterior motor which is used in e-bike....
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2answers
2k views

Selection of PWM switching frequency in BLDC motor

Is there any method or formula for selecting PWM switching frequency based on measured motor parameters for controlling BLDC motor?
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1answer
928 views

Problems in design of a BLDC motor driver

I have been building a driver circuit for a RS2205 BLDC motor and have gotten decent results so far using back EMF feedback for commutation control. The motor is driven by a PWM wave from a Arduino ...
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1answer
1k views

is there a calculation for no load current on BLDC motor?

I am calculating various values for a range of motors. However, I need to find the no load current of a motor or io to allow me to calculate other values, based on the information I have below for a ...
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1answer
127 views

Compact small electricity generator using induction coil

Traditional brushless motors use wound induction coils surrounded by permanent magnets. Would it be possible to create a less efficient version generator by rearranging the orientation of the coils to ...
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313 views

Relationship between offset in electrical angle and BLDC motor performance

I am controlling a BLDC motor using Field Oriented Control (FOC). I use a 14-bit absolute encoder to read the rotor's position \$\theta_{m} \$, and use it to reconstruct the electrical angle \$\theta_{...
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1answer
1k views

BLDC Calculation for Back EMF

I have a brushless DC Motor that i am considering buying from hobbyking.com with 2100Kv (RPM/v) i am trying to follow the equation on Wikipedia's motor constants page i have included the equation here ...
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1answer
455 views

Changing current limit on a cheap BLDC motor controller

These are my options: 250 W, 12 - 24 V, no A information, assuming 250/12≃20 A 500 W, 12 - 36 V, 15 A If used with a BLDC motor of lower power with lower maximum allowed current, what are the ...