Brushless DC Motor

Posted by KBV Research on December 5th, 2019

Brushless DC motors are common throughout the world in industrial applications. Brushed and brushless motors are available at the most basic level, and DC and AC motors are available. As people might understand, brushless DC motors do not contain brushes and use a DC. These motors offer a lot of specific advantages over other types of electrical motors.

What is a brushless DC Motor?

The basic operating principle for the brushed DC motor and the brushless DC motor is the same, i.e. feedback from the internal shaft position. A brushless DC motor (also called as a BLDC motor or BL motor) is a DC motor that has no brushes. Such types of motors are highly efficient over a wide speed range in generating a large amount of torque. Permanent magnets rotate around a fixed armature in brushless motors and solve the problem of binding current to the armature. Electronics commutation has a wide range of functionalities and flexibility. They are known if they are stationary for smooth operation and retaining torque.

How does a brushless motor work?

Even though brushed motors are inexpensive, efficient and have a high torque or inertia ratio, they also have a host of drawbacks. Through time, these components wear out producing dust. To clean or replace the brushes, this type of engine requires regular maintenance. Because of rotor limitations, high rotor inertia, low maximum speed, and electromagnetic interference (EMI) due to arcing on the brushes, they also have low heat dissipation ability.

Brushless DC motor only has two basic components called rotor and stator. The rotor is the rotating part with rotor magnets, while the stator is the stationary part and contains windings of the stator. In brushless DC motors, permanent magnets are mounted in the rotor and the electromagnets are moved to the stator. For shaft turns, the high-power transistors are used to allow electromagnets. The controller uses a solid-state circuit to perform the distribution of power.

What are brushless DC motors used for?

Usually, brushless DC motors are 85-90 percent efficient, whereas brushed motors are typically just 75-80 percent efficient. Eventually, brushes wear out, sometimes triggering dangerous sparking, reducing a brushed motor's lifespan. Brushless DC motors are quiet, lighter and their lifespan is much longer. Because the electrical current is controlled by computers, brushless DC motors can achieve much more accurate motion control.

Due to all these benefits, brushless DC motors are also used in modern devices requiring low noise and low heat, especially in continuously operating devices. Washing machines, air conditioners, and other consumer electronics may be included. They may even be the key source of power for service robots, which for security reasons would require very careful force control. Brushless DC motors offer many distinct advantages over other types of electric motors, which is why they have spread into so many household items and can be a key factor in the growth of service robots within and outside the industrial sector.

Applications of brushless DC motors

1. Transport

Brushless motors are found in electric vehicles, hybrid vehicles, and personal transporters. Most electric bicycles use brushless motors that are often built into the wheel hub itself, with the stator fixed to the axle and the magnets are attached to and rotating with the wheel. In self-balancing scooter wheels, the same principle has been applied. Due to their high performance, most electrically powered RC models use brushless motors.

2. Heating and ventilation

In the heating, ventilation and air conditioning (HVAC) and refrigeration industries, there is a trend towards the use of brushless motors instead of different types of AC motors. The most important reason for switching to a brushless motor is the dramatic reduction in power required to operate against a conventional AC motor. While shaded-pole and permanent split capacitor motors once monopolized as the fan motor, many fans are now running with a brushless motor. In order to improve the overall system efficiency, some fans also use brushless motors.

3. Industrial engineering

In industrial engineering, the application of brushless DC motors mainly focuses on manufacturing engineering or the design of industrial automation. Brushless motors are predominantly used in manufacturing for motion control, positioning, or actuation systems. Due to their high power density, high efficiency, good speed-torque characteristics, wide speed ranges, and low maintenance, brushless motors are better suited for manufacturing applications. Linear motors, actuators for industrial robots, servomotors, extruder drive motors and feed drives for CNC machine tools are the most common applications of brushless DC motors in industrial engineering.

To sum up

The brushless DC motor market is witnessing growing popularity due to a component called electronic commutation that has been able to replace conventional mechanics. In summary, brushless motors are way better than brushed ones. Users will benefit from reduced maintenance, increased efficiency, reduced heat, and noise.

The brushless motors are one or more permanent magnet synchronous units. Power tools are now considered high-end devices with a brushless motor. In the future, they have been expected to see brushless DC motors being used in a wider range of applications. They will likely be widely used, for example, to drive service robots— a small robot delivering services in fields other than manufacturing.

In this type of application, one might think stepper motors would be more suitable, where pulses can be used to control positioning precisely. But BLDC motors are better suited to control force. And with a stepper motor, it would take a relatively large and steady current to hold the position of a device such as a robot arm.

A current proportionate to the external force is all that would be required with a BLDC motor— allowing for more power-efficient control. In golf carts and mobility carts, BLDC motors may also replace simple brushed dc motors. In addition to improving their efficiency, BLDC motors can also provide more accurate control, which in turn can prolong the battery life further. The Global Brushless DC Motor Market size is expected to emerge at a market growth of 6.7% CAGR over the forecast period.