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. 

The inventors of the brushless motor are the German theoretical physicist Ian Kolander Rayor (Ernstwerner Siemens) and the doctor Angel Delfuri (Angel of austodori). As early as the 1860s, the German physicist Rayor began to study the working principle of the motor.In 1886, the first practical DC motor that could operate at a constant speed at a variable weight was introduced. FrankJulianSprague was its inventor, and it was this motor that provided the catalyst for the widespread use of electric motors in industry.In 1949, Slovak engineer Emil Petrash invented the first brushless DC motor, which used the principle of reversing alternating current to achieve uninterrupted rotation. This marked the beginning of the era of brushless motors.The practical motor adopts brushless form, that is, ac-flow squirrel cage asynchronous motor, which not only eliminates the spark and voltage loss at both ends of the winding, but also can transmit power at a constant speed. However, the asynchronous motor has many insurmountable defects, so that the development of motor technology is slow.By the 1960s, the American electrical engineer Terry Laikin invented a three-phase brushless motor with strong magnetic force and efficient performance (the phase of the three-phase motor refers to the coil winding in the motor, three phases and three windings. Specifically, it includes three phases, that is, phase A, phase B and phase C. The three-phase motor uses the three-phase power supply as energy, and generates a rotating magnetic field through three independent coils to drive the motor to rotate). This innovation broke the working principle of the traditional motor and was hailed as a revolutionary breakthrough in the history of the motor, and Terry Laikin became the father of the brushless motor. Since its invention, compared with the brushless motor, the brushless motor has low noise, lower maintenance cost, more reliable performance, lower failure rate, better external characteristics, small no-load current, wide speed range and other characteristics, since the 1960s, Europe, Japan, South Korea and other countries and regions have carried out research on brushless motors. And in aerospace, robotics, consumer electronics and other fields of application. At present, China has also become one of the major countries in the production and application of brushless motors in the world. 

The factory has newly purchased state-of-the-art automated equipment for upgrading.Welcome both new and existing customers to visit our factory.

Adjusting the speed of the brushless DC motor can be achieved in the following ways: 1. Regulating voltage:The input voltage of the motor is adjusted by changing the output voltage of the driver, thus changing the speed of the motor.2.PWM speed regulation:Using pulse width modulation (PWM) technology, the constant DC supply voltage is modulated into a pulse voltage sequence with fixed frequency and variable width.By changing the duty cycle of the PWM (that is, the time ratio of the high level to the low level), the average output voltage can be adjusted to change the speed of the motor. 3. Series resistance speed control:A potentiometer is connected in series in the motor circuit to adjust the speed of the motor by changing the size of the resistance.This method is suitable for low power motors, but is less cost-effective for high power motors due to the need to find a high power resistor with the right resistance value.4. Change the power-on sequence:For the case that the steering needs to be changed, it can be achieved by changing the order of the power-on of the phases.For example, the running direction of the motor can be controlled by connecting terminal dir and terminal com.