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What is a Brushless DC motor? Controls, Applications & Types

A Brushless DC (BLDC) motor is an electric motor that functions without using brushes and a commutator. In recent times, it has risen in popularity because of the many advantages it provides over conventional motors. For instance, a BLDC motor is more efficient and hence ensures tremendous cost savings. The main reason for a BLDC motor’s efficiency is its mode of operation. Moreover, as it does not rely on brushes that are vulnerable to wear and tear, it lasts for a longer time.

What is a Brushless Motor Exactly?

Brushless DC motor (BLDC) can be comprehended better by looking at its functionality in detail. A BLDC motor uses electronic controllers to perform commutation, which is the process of switching the direction of current in the motor coils with the purpose of generating rotational motion. Therefore, it provides numerous advantages over conventional motors such as greater control and overall enhanced power density.

Since the launch of the first brushless motor in the 1960s, the BLDC motor technology has evolved rapidly. Therefore, BLDC motors have become the preferred motor type in various industries such as automotive, consumer electronics, industrial automation, and robotics.

Popular Applications of BLDC Motors 

Brushless DC motor has become the favourite type of motor in various industries due to the immense cost-savings it offers. Below are some of its mainstream applications in the modern times:

1. Electric Vehicles (EVs)
2. Drones and UAVs
3. Industrial Automation
4. HVAC Systems
5. Computer Peripherals
6. Consumer Electronics
7. Medical Devices
8. Aerospace
9. Electric Power Tools
10. Automotive Systems
11. Pumps and Compressors
12. Renewable Energy Systems

Various Types of Brushless Motors Used in the Modern Times

Below are different types of brushless motors that are used in modern times in various industries

• Outrunner Brushless Motor: This high torque brushless DC motor comes with a rotating outer shell, and is often preferred for applications that need high torque and low RPM.

• Inrunner Brushless Motor: This high rpm high torque motor is a compact motor with the rotor inside the stator. Mostly these types of motors are used for higher RPM applications with limited space.

• Hall Effect Sensor Equipped Motors: These are motors with integrated Hall sensors for accurate rotor position feedback, used in applications requiring precise control.

• Permanent Magnet Synchronous Motors (PMSM): These are high-efficiency motors that use sinusoidal commutation.

• Sensorless Brushless Motors: These motors operate without traditional position sensors, relying on advanced control algorithms and back EMF for position estimation.

• Stepper Motors: These motors offer controlled rotational movement in discrete steps, used in applications like 3D printing and CNC machines.
• Linear Brushless Motor: This high speed and torque DC motor produces linear motion along a track. They are popular in industries like automation and semiconductor manufacturing.

• Multirotor Motors: These are lightweight, high-RPM motors, which are designed for drones and other multirotor aircraft.

Brushless DC motor: Control Methods

Below are some of the control methods for BLDC motors:

Sine wave control

Sine wave control utilizes the SVPWM wave and delivers the output in three-phase sine-wave voltage, and the corresponding current is sinusoidal current. In this control mode, there’s no paradigm of commutation as the square-wave control. Moreover, the system does not think that infinite commutations have taken place within an electric cycle.
Square-wave control

Square-wave control implement Hall sensor or sensor less estimation algorithm to find the position of the motor rotor. After that, it commutates six times in the 360° electrical cycle as per the position of the rotor.

FOC control

Sine wave control directly figures out the control of voltage vector and indirectly realizes the current control. However, it cannot control the current direction. We can think of FOC control as an upgraded sine wave control as it realizes the control of current vector.

Final Thoughts

BLDC motors have been a godsend for companies looking to save money and bring in higher work efficiency in industrial operations. The rapid evolution in BLDC technology has resulted in the creation of different types of motors that use a variety of control methods and deliver top performance in multiple applications. However, if you want to make the most of a BLDC motor, you need to procure it from a brushless DC motor supplier with a proven track record of supplying well-tested motors.

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