Brushless motor is a synchronous motor that uses DC power supply and realizes commutation function through electronic commutator without carbon brush and commutator, thus avoiding friction loss, spark interference and maintenance costs. Brushless motor has the advantages of high efficiency, high performance, low noise, low vibration, long life and high reliability. This paper introduces the classification of brushless motors.Classification of Brushless DC Motors1. External rotor brushless DC motor: This external rotor BLDC motor is basically the opposite of the type of internal rotor brushless motor. Also known as an external rotor brushless motor, it uses a rotating housing around a fixed internal component. External rotor BLDC motors typically use a higher number of permanent magnet poles on the rotor. This means more torque and smoother operation. The main disadvantage of the external rotor brushless DC motor is its slow speed. As a result, these types of motors are better suited for low-speed, high-torque applications.2. Inductive brushless DC motor:BLDC motor with Hall sensor is a motor that relies on the sensor to provide rotor position data. These types of brushless motors provide reliable performance at lower speeds. At lower rotational speeds, the sensor provides accurate data for smooth rotation. The motor with sensor will have the problem of delayed feedback at higher speeds, and harsh conditions such as magnetic interference or high temperature environment will also affect the sensor work, thus affecting the motor operation.3.  Sensorless brushless DC motor: This type of motor does not use Hall sensors. Instead, the controller relies on the back electromotive force generated in the stator coil to calculate the rotor position. These types of brushless DC motors offer the best performance at high speeds. You can also use them in high temperature environments because they do not use sensors. When the back electromotive force is too low or at rest to be read by the controller, the motor cannot be accurately controlled, so these motor types are suitable for high-speed, low-cost applications.4.  Single-phase brushless DC motor: the rotor used by the single-phase brushless motor is composed of a pair of north and south poles. This type of brushless DC motor design has its advantages and disadvantages. The advantage is that the motor can initially reach a very high rotation speed. On the downside, the performance of unipolar motors decreases significantly at lower speeds, which affects rotational stability and efficiency. Three-phase brushless motors use multiple magnetic poles on the rotor, up to 12 or more. As mentioned earlier, they are placed so that the opposite poles face each other. More magnetic poles provide smoother rotation, but at the expense of speed. Therefore, these types of brushless motors cannot reach high speeds and are suitable for applications with low speeds and high torque.5.  Sine wave drive brushless DC motor: sine wave driver rotates the rotor by continuously changing the voltage of the stator coil in a sinusoidal manner according to the rotation Angle of the rotor. The three phases of the motor "delay" for a specific amount of time, depending on the frequency.6.  Square wave drive brushless DC motor: square wave drive is the simplest way to drive. It switches the ON/OFF state of the electronic components according to the rotation Angle of the rotor, and then changes the direction of the current in the stator coil, thus making the rotor rotate. The rotor rotates once and the current direction changes 6 times.ConclusionSince the invention of the brushless motor, it has been plagued by technology, cost, process and other problems until the beginning of the 21st century. When the technical problems are gradually solved, the brushless motor with its excellent performance and characteristics will gradually be recognized by all walks of life, and the market share of brushless motor and its derivative products will grow rapidly.

Before understanding the working principle of brushless motors, let's first learn the right-hand screw rule two (ampere rule two), as shown in the following figure:When we hold the solenoid with the right hand, the four fingers point to the direction of the current, then the end pointed by the thumb is the N pole of the solenoid, and if the current is in the opposite direction, the north and South Pole are switched positions.As shown in the figure above, we wind the stator around the coil and pass a certain current through the coil to generate a magnetic field. Lorentz's law of force states that as long as a current-carrying conductor is placed in a magnetic field, it will experience a force. Due to the reaction force, the magnet will experience equal and opposite forces. When the coil through the current, will produce a magnetic field, the magnetic field is driven by the stator's magnetic pole, the same pole repel each other, the opposite pole attracts each other, if you continue to change the direction of the coil current, then the rotor induced by the magnetic field of the magnetic pole will continue to change, then the rotor will be rotating under the action of the magnetic field.The switching sequence of the current is mainly realized by the Hall sensor, which is mainly used to determine the conduction Angle of the power transistor in the electronic commutation circuit drive circuit, so as to determine the magnetic state of the armature field. The position of the pole of the rotor permanent magnet relative to the stator armature winding is detected by it so as to determine the switching sequence of the power transistor in the electronic commutation drive circuit.In addition to Hall magnetic sensors, brushless motors can also use other sensors, such as photoelectric and electromagnetic sensors. 

Structural AspectBrushless DC Motor: consists of a motor body and a driver, including a rotor, a stator, a sensor and an electronic controller. There is no brush and commutator, relying on the electronic controller to control the direction and size of the current in the stator winding according to the rotor position information detected by the sensor to realize the rotation of the rotor.Brush DC Motor: mainly composed of a stator (usually a permanent magnet), a rotor (composed of winding), a brush and a commutator. The brush and commutator change the direction of the current through mechanical contact, so that the rotor continues to rotate.Performance AspectBrushless DC Motor: higher efficiency, generally 85%-90%, more stable operation, low noise, almost no electrical spark, electromagnetic interference is small, due to the reduction of mechanical wear parts, long service life.Brush DC Motor: the starting speed is fast, the torque is large, but the mechanical friction between the brush and the commutator will lead to greater noise and heat during high-speed operation, and will also produce electrical sparks, which may cause electromagnetic interference to other equipment, and the efficiency is generally 75%-80%.Control AspectBrushless DC Motor: requires a complex electronic control unit to achieve accurate commutation control, usually using digital control technology, according to the rotor position sensor feedback information, precisely control the current in the stator winding on and off and order.Brush DC Motor: The control is relatively simple, by adjusting the size and direction of the DC voltage applied to both ends of the brush, you can control the speed and steering of the motor, which can be controlled by traditional analog circuits such as thyristor.Application AspectBrushless DC Motor: suitable for applications requiring high efficiency, noise, life and control accuracy, such as drones, electric vehicles, industrial automation equipment, high-end home appliances, etc. Brush DC Motor: Often used in cost-sensitive, precision requirements are not high, the need for large starting torque occasions, such as electric toys, some traditional power tools, small appliances, etc. Cost AspectBrushless DC Motor: Due to the need for components such as electronic controllers and position sensors, and high manufacturing process and material requirements, manufacturing costs are high.Brush DC Motor: simple structure, mature production process, low manufacturing cost. 

BLDC (brushless DC) and AC (alternating current) motors differ in their power source, internal construction, and control methods.While both Brushless DC (BLDC) motors and AC motors are ubiquitous in modern appliances and industry, they operate on fundamentally different principles. The core distinction lies in their power source, control method, and internal construction.1. Power Source and Current Type:As their names imply, a BLDC motor runs on direct current (DC), while an AC motor operates on alternating current (AC). This is the most fundamental difference. However, a BLDC motor often incorporates an internal inverter to convert DC into a controlled three-phase AC supply, which can cause confusion.2. Commutation Method:This is the most significant technical difference. Commutation is the process of switching the current in the motor's windings to create rotational motion.AC Motors (Induction): The most common type, the induction motor, relies on a rotating magnetic field generated by the AC power in the stator. This field induces a current in the rotor, creating motion without any physical electrical connection to it—a phenomenon called electromagnetic induction.BLDC Motors: These are electronically commutated. They require an external controller or driver. This controller uses sensors (or sensorless techniques) to determine the rotor's position and precisely switches the DC power to the stator windings at the correct moment to keep the motor turning.3. Construction and Performance:Construction: A standard AC induction motor has a simple, rugged design with a squirrel-cage rotor, making it robust and low-cost. A BLDC motor has permanent magnets on its rotor and fixed windings on its stator, eliminating the brushes found in traditional DC motors.Control and Efficiency: BLDC motors excel in controllability. Their electronic commutation allows for precise speed and torque control, high efficiency, and a high power-to-size ratio. AC induction motors are simpler to operate (often just plug into AC power) but are generally less efficient and harder to control precisely without a variable frequency drive (VFD).In summary, choose an AC induction motor for simple, robust, and cost-effective applications like compressors or conveyor belts. Opt for a BLDC motor when you need high efficiency, compact size, and precise electronic control, as seen in drones, computer fans etc.开启新对话

Wenzhou Tuoke Drive Technology Co., Ltd. and Zhejiang Zhengke Electromotor Co., Ltd. Establish Strategic Partnership!Click to visit → https://www.zhengke-motor.com/This announcement is jointly provided by Wenzhou Tuoke Drive Technology Co., Ltd. and Zhejiang Zhengke Electromotor Co., Ltd. For further resources and information, please visit the official website of our partner.

When choosing between a BLDC (Brushless DC) motor and a traditional DC motor, the best option depends on your needs. Here’s a comparison to help you decide: 1. Efficiency & PerformanceBLDC motors are more efficient (80-90%) because they don’t have brushes, reducing energy loss. They also provide smoother operation and higher speed control.DC motors are less efficient (70-80%) due to brush friction, which causes wear and energy waste. 2. Lifespan & Maintenancemotors last longer because they have no brushes to replace. They are ideal for applications requiring long-term use, like electric vehicles and drones.DC motors need regular maintenance since brushes wear out over time, making them better for short-term or low-cost projects.3. Cost & ComplexityDC motors are cheaper and simpler, making them good for basic tasks like toys or small appliances.BLDC motors are more expensive due to their electronic controller, but they save money in the long run with lower energy bills.4. Best UsesBLDC motors → High-performance needs (e.g.,industrial machines).DC motors → Simple, budget-friendly tasks ConclusionIf you need efficiency, durability, and precision, choose a BLDC motor. BLDC motors exhibit higher efficiency since they do not lose energy through friction and heat generation associated with brushes. Reduced maintenance is a significant upside; without brushes, there is no need for replacements or cleaning associated with brush degradation.