# 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.

588 questions
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### Why do BLDC motor (1 kW) controllers have so many MOSFETs?

I have a 1 kW three-phase BLDC motor from China, and I was developing the controller myself. At 48 Vdc, the maximum current should be about 25 Amps and a peak current of 50 Amps for short durations. ...
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### Sensorless speed control and startup of BLDC

Regarding the sensorless speed control of a BLDC, I have some doubt about what may happen in two scenarios when the rotor's position is unknown: 1) the start-up from zero and 2) with an initial ...
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### How to control 4 motors which are conected to a flight controller using Raspberry Pi?

I just started a project to make a drone without a radio controller. I want to control 4 brushless motors connected to a flight controller KK 2.1.5 using Rpi 3 B+. Obviously, the motors are first ...
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### Formula for RPM and its relation with slot stator

I want to clarify a formula regarding RPM. The formula $\mathrm{RPM} = 120f/p$ where $f$= frequency and $p$= # of poles. But what if the motor has different slots, for example, a 24 slot stator ...
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### BLDC Motor Drive control

I am using a 310VDC, 4pole BLDC motor with hall sensor feedback for my application. My objective to run the BLDC motor at 7500 rpm. My motor rated speed is 8500rpm. I am able to run motor at 7500 ...
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### Why does shorting the phases of a BLDC motor cause it to lock?

Normally a motor can be locked by shorting its phases. When the motor is not connected and we short all the the three phase terminals (tie them together) and try to rotate the shaft it offers lot of ...
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### What is causing these switching transients on a 3 phase motor driver?

One time I built a 3 phase motor driver, which works quite well in the original configuration. Recently, I changed the physical layout to this rectangular form factor, and now it has quite large ...
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### Identification of BLDC Motor

I would to know if make sense to obtain the current of the BLDC motor, using the BLDC motor torque measurement. In particular, i'm able to measure the torque of a BLDC motor but not the current that ...
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### SVPWM for BLDC Motors: Switching Losses vs Neutral Point Voltage Swing/fluctuation

I am implementing a SVPWM (Space Vector Pulse Width Modulation) scheme for a 3-phase inverter (3 H-bridges, nothing fancy) to control a BLDC Motor. Since one can choose which zero vectors (000 or 111)...
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### 3 phase Bldc hall sensor problem

I am trying to drive a 350 watt, 3 phase, BLDC motor (DGW07-20j model) with stm32 micro controller. But I have problem with hall sensors because their outputs are not similar to the hall sensors which ...
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### BLDC hall sensor output problem

The Hall sensor output is weird. First, I use 5V power supply connected to the Hall sensor power cable. Then, the outputs give me three high levels. Whatever how I rotate the motor, the output does ...
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### How can I run my e-bike wheel on AC power?

I have an electric wheel designed for an electric bicycle conversion. By my understanding, the wheel is essentially a 48V, 1000w rated brushless DC motor. It comes with a thumb throttle and kill ...
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### DIY rotary inverter technical and economical feasibility

I’m setting up a solar panel system (200W) that’s used to charge batteries that will power small appliances in a converted van. Solid state inverters are expensive and difficult to fix and it seems ...
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### How to determine PWM Frequency of a MOSFET to drive a BLDC motor?

What are the factors determining the PWM Frequency of the MOSFET driver circuit that drives a BLDC motor. Is there any equation for PWM calculation? For eg. I need to control the speed of a BLDC ...
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### Paralleling output of multiple BLDC motors used as generators

First of all, I apologize for anything stupid I say as I am not yet well versed in the proper technical terms and schematics. I wish to use several identical BLDC motors that will be spun at the same ...
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### Magnetic Flux loss in PM Motors

The PM motors specially BLDC or PMSM they get their armature energy from the permanent magnets on their rotors unlike the Induction Motors in which the armature gets its energy from the Stator ...
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### Driving a 4-wire Hard Drive Motor

After reading many contradictory accounts of the "proper" method, I would like to clear it up: what is the correct method for driving a 4-wire, star configuration hard drive motor? What I have ...
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### Measuring inductance of a BLDC motor

I'm trying to drive a BLDC motor typically found in a hoverboard. I don't have much information about the motor since there was no spec sheet that came with it. Only that it is a 350W, 36V motor. I'm ...
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### How to find the optimal speed of a BLDC motor having hall sensors? Can we change the most efficient speed through the controller? [closed]

How do we find the speed of BLDC motor at which it has minimum electrical losses so that we design a gearing system accordingly. And can we change the most efficient speed of a BLDC motor to suit our ...
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### PWM speed control of 24V DC Brushless Pump

I would like to PWM speed control a 24V 2A DC Brushless Pump using an Arduino for my nano-brewery project. I've been searching for a Speed controller on Amazon or Ebay. But, i either find brushed ...
407 views

### Difference between Field Oriented Control and Direct Torque Control

What is the fundamental difference between Field Oriented Control (FOC) and Direct Torque Control (DTC) (say for an induction motor)? Is it really the same as described in https://www.researchgate.net/...
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### BLDC won't start up by itself but with some initial help

As stated in the heading, I'm currently having a problem with driving a BLDC motor with VCC being 30 V. I'm using the DRV8320S motor driver IC from Texas Instruments. It is configured in 1x PWM ...
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### Mosfets heat up in a BLDC controller

I am trying to build a bldc controller. I have the following schematic I should mention that for the gate drivers I used ir2101 ICs. Everything works fine but when I connect the motor (350w ...
75 views

### Slew Rate related EMI: How relevant is it for motor control circuits ?

I am designing a 3-phase inverter board for BLDC Motor control. The H-bridges i use are IFX007 from Infineon. The mentioned IC has the possibility to adjust the slew rate. From what i have read, i've ...
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### Understanding parts of this BLDC driver schematic

I have a couple of question on ST's STSPIN32F0A 3-phase BLDC driver and I was hoping someone can help me figure out some parts of the schematic. The schematic shows the STSPIN32F0A (pg. 1) connected ...
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### Back EMF sensorless BLDC control

I am trying to detect the zero crossing point of back emf in a bldc motor in order to control it sensorless. Do you have any idea what detection circuit should I use. I am thinking about a network ...
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### How to identify phases of BLDC motor without rotating?

I picked up a Wye-wound brushless DC motor with three leads, three wires coming out of it via a flex PCB. Unfortunately, this flex PCB has no color indication. How can I figure out which lead is ...
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### Three phase motor driver DC link, DC bus capacitor values

I am designing a motor driver for a three phase brushless motor and have been looking for a capacitor value for the DC bus of this circuit (C1). Most of what I have found when researching deals with ...
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### BLDC Motor rotor vibrates with audible high pitch beep, but does not spin. Controlled by custom motor controller

The circuit I have built (taken from the HIP4086A gate driver data sheet found at https://www.intersil.com/content/dam/intersil/documents/hip4/hip4086-a.pdf) is: The only difference between this ...
222 views

### How to drive 4-pin fan

I've been attempting to get this 4-pin brushless dc pc fan working for some time now. It has a red (+) black (-) blue (PWM in) and yellow (tachometer out). I only want this fan running at maximum ...
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### Issue with driving Brushless Motor with a MOSFET Driver

So I have been given a circuit which supposedly works. The circuit was the the one shown but with a 10k resistor where the scribbles are. Q17 is an IRLM6344TRPbF N-chanel MOSFET and Q16 is a ...
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### Is this basic schema of a brushless driver correct?

So you have the "logic" part that runs at 0-5V. The controller is a microprocessor that can read out the current monitors and respond to them by changing the voltages by changing the connection of the ...
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### BLDC (Brushless DC Motor) vs PMSM (Permanent Magnet Synchornous Motor)

The differences between BLDC and PMSM are very small and for what I have seen while reading about it, is not clear to many of us. Most of the articles I have read say that the main difference is that ...
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### hard drive BLDC motor

I can't work out what the issue with my setup to control a 2.5" hard drive BLDC motor is. I have a 3 pole 2.5" hard drive connected to the following drive circuit, but the motor isn't spinning. ...
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### What PWM inputs are needed to drive a 3 phase BLDC using the HIP4086 IC driver chip?

I am building a motor controller for a BLDC (w/ Hall sensors) using a Teensy. My circuit looks like the typical application diagram in the datasheet (https://www.intersil.com/content/dam/Intersil/...
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### Dc motor as torque transducer for BLDC motor

I bought a cheap BLDC motor on some Chinese website and could not find its characteristics. However, I have A28-400 24V amp flow Dc motor with its characteristics. If I'm able to build a test rig to ...
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### Brushless motor esc and voltage [closed]

If brushless motor work in 22.2 volt , if I provide the ESC with 24 volt Is there a problem ? Thanks
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### BLDC Motor Performance at high altitude?

How does a BLDC motor performance change at high altitude where the air density is really low? For example, say I have a given BLDC motor with given torque-RPM performance curves. Now, I assume these ...
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### Pull-up scheme for Hall effect sensors on a BLDC

I looked around on here, and used google, and couldn't find a direct answer to this question. Please forgive me if I overlooked something. I am working on a board to control a BLDC motor (BLWS231D-...
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### How can I get/calculate simulink bldc parameters

I tried to get the parameters for a bldc simulation https://de.mathworks.com/help/physmod/sps/ref/brushlessdcmotor.html I tried to find a similar motor to the I need (500 W, 20-25 Nm, geared bldc) ...
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### Simulating 3 phase mosfet bridge with LEDs

I have a commercial 3 phase BLDC motor driver board (TI DRV8323 BoostXL) and I want to write a firmware from scratch. For testing, I want to make sure I open/close the mosfets in correct order. I am ...
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### BLDC Motor Constants: Why is my Kt and Ke different?

I'm new to working with motors. Reading up on BLDC theory, it is repeatedly said that in SI units, the Ke and Kt will be numerically equal. I downloaded the motor spec excel sheet of the T1101 motor ...
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### FOC speed limit motor?

I have here an FOC controller with encoder and a 2200kv, 40A, 324W motor. I can run the motor just fine and I limited the current to 4A and the motor spins up to around 1400rmp. When I now increase ...
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### FET Switching Loss in BLDC Inverter

I'm designing an inverter for trapezoidal control of a 500W BLDC motor, using DRV8301 for the gate driver. My switching frequency is 10Khz, Vdd is 48V, and Imax=20A. I've been trying to calculate the ...
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### How to calculate voltage ripple in a BLDC filter module?

Hi I need some calculation for my thesis. A found this picture on the internet. My project is almost the same. It's a pi filter for a 3 phase BLDC. The peak current is 60A. It runs from 12V car ...
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### BLDC Transfer Function Inductance Value

I realize a very similar question has been asked here, but I'm slightly confused about the derivation, specifically the quantities Lq and Rq which refer to the armature inductance and resistance. I'm ...
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### Difference between lower and higher current rated ESCs and electric skateboard questions

I am starting a project and would like to build an electric skateboard. Here are the specs for the parts that I have gathered so far: a. Two 90mm wheels that each contain a built-in BLDC motor. The ...
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### Can 3 phase AC current be applied to a BLDC and vise versa?

I am just wondering because the designs of a synchronous motor and BLDC are the same. Could you please explain the downsides of not using the designated current?