What is the difference between a brush motor and a brushless motor?
With the increasing popularity of electric vehicles and the fierce competition in the market, many companies and merchants have made advertisements in addition to the price and appearance of the products, and also advertised in the small details of electric vehicles. The most popular is the brushing and brushless promotion of the motor, and the advertising of the brushless motor is one of the highlights. When you see this noun, you can't help but think that if there is no brush, there must be a brush, so where is the difference between brush and brushless? The following small series will answer you for you.
Definition of brush motor and brushless motor
Brushed motor: A brushed motor is a rotating electrical machine that contains a brush device that converts electrical energy into mechanical energy (electric motor) or converts mechanical energy into electrical energy (generator). The brush motor is the basis of all motors. It has the characteristics of quick start, timely braking, smooth speed regulation in a wide range, and relatively simple control circuit.
Brushless motor: The brushless DC motor is composed of a motor body and a driver, and is a typical mechatronic product. Since the brushless DC motor is operated in a self-controlled manner, the starting winding is not added to the rotor like the synchronous motor with heavy-load starting under the variable frequency speed regulation, and the oscillation and the out-of-step are not generated when the load is abrupt. The permanent magnets of the medium and small capacity brushless DC motors are now mostly made of high magnetic energy product rare earth neodymium iron boron (Nd-Fe-B) materials. Therefore, the volume of the rare earth permanent magnet brushless motor is reduced by one frame number compared with the same capacity three-phase asynchronous motor.
The difference between the two
1. When the brush motor is working, the coil and the commutator rotate, the magnetic steel and the carbon brush do not rotate, and the alternating change of the coil current direction is completed by the commutator and the brush that rotate the motor. In the electric vehicle industry, there are brush motor divided into high speed brush motor and low speed brush motor. There are many differences between brush motor and brushless motor. From the name, it can be seen that the brush motor has a carbon brush, and the brushless motor has no carbon brush.
2. The brushless DC motor is composed of a motor main body and a driver, and is a typical electromechanical integration product. Since the brushless DC motor is operated in a self-controlled manner, it does not add a start winding to the rotor like the synchronous motor that is restarted under variable frequency speed regulation, and does not cause oscillation and out-of-step when the load is abrupt.
3, brush motor is a traditional product, the performance is relatively stable.
Brushless motors are upgraded products that have better life performance than brushed motors. However, its control circuit is more complicated, and the aging screening requirements for components are more stringent. Although the motor has a long life, the control circuit is prone to problems. Therefore, brushless motors are subjected to rigorous reliability tests to ensure quality. However, with the continuous upgrading of technology, the brushless motor technology is quite mature.
4. In the actual production process, since the brushed toothed DC motor is a high-speed motor, the gear teeth are small and easy to wear, but the force is large and the climbing ability is strong. The brushless DC motor eliminates the trouble of replacing the carbon brush for two or three years in the process of use. However, due to the process of controlling the brushless motor, the accuracy is extremely high. Moreover, the price of the brushless motor controller is also higher. In contrast, there is a brushless toothless DC motor. Although it is necessary to replace the carbon brush, it is very easy to replace the carbon brush, and the motor control is relatively simple, the motor runs smoothly, and the safety factor is high.
5. Brushed motor means that the motor is a DC input. The controller that controls it can only adjust the speed by supplying the current. The brushless motor is actually a three-phase AC motor. The controller converts the DC power into three phases. AC power, and commutating according to the sensor Hall element in the motor to make the motor run normally. Directly speaking, a brushless motor has a longer life than a brushed motor, and it has a strong power to start, but the controller is more expensive than a brushed controller. At present, all of them are brushless controllers, and the brush has been basically eliminated. The electric vehicle controller is the core control device used to control the start, run, advance and retreat, speed, stop, and other electronic devices of the electric vehicle. It is like the brain of an electric vehicle and an important component of an electric vehicle.
