1. Operation Principle of Brushless Motor

                  2019-10-11 766

                        Operation Principle of Brushless Motor

                    Motor driven control is to control the rolling or stop of the motor and the rolling speed. Electric speed controller (ESC) is also called electronic speed regulator for short. The motor used in electric regulation is different, which can be divided into brushless regulation and brushless regulation.

                    The permanent magnet of the brush motor is fixed. The coil is wound around the rotor. The magnetic field direction is changed continuously by contacting the commutator with a brush to keep the rotor rolling. Brushless motor, as its name implies, has no so-called brush and commutator, its rotor is permanent magnet, and the coil is fixed, directly connected to the external power supply, the problem arises, how to change the direction of the coil magnetic field? In fact, an electronic governor is needed outside the brushless motor. This governor is a motor drive. It changes the direction of the internal current of the fixed coil at any time to ensure that the force between the brushless motor and the permanent magnet is mutual squeezing and the rolling can continue.

                    Brush motor operation can be operated without electric adjustment, directly supplying electricity to the motor, but it can not control the speed of the motor. It is necessary to adjust the brushless motor, otherwise it can not roll. It is necessary to convert direct current into three-phase communication power through brushless adjusting, and then transfer it to brushless motor to roll.


                    The earliest adjustments are not the same as the current ones. The earliest ones are all brush adjustments. You may ask what is brush adjustments and what is the difference between brushless adjustments and brushless adjustments. In fact, the difference is great. Brushless and brushless adjustments are based on the motor. Now the rotor of the motor is all magnet blocks, and the coil is stator rolling. Because there is no carbon brush in the center, this is the brushless motor. Brush motors, as the name implies, are carbon brushes, so they are brush motors. For example, the motor for a remote control car with a price of 120 yuan, which we usually play with children, is brush motors. Electric tuning is named brushless tuning and brushless tuning based on these two motors. From a professional point of view, the output of BLDC is DC, and the output of BLDC is three-phase communication. Direct current is the electricity stored in our batteries. There are positive and negative poles. The 220V power supply for mobile phone charger or computer is communication power. Communication electricity is with a certain frequency, which is simply a line of positive and negative, positive and negative back and forth exchange; direct current is the positive pole is the positive pole, the negative pole is the negative pole. If the communication and direct current are clear, what is "three-phase electricity"? In theory, three-phase communication power is a transmission mode of electricity, referred to as three-phase power, which is composed of three communication potentials with the same frequency, equal amplitude and 120 degrees of phase difference in turn. Simply speaking, the three kinds of communication electricity in our family are the same except for the different voltage, frequency and driving angle. Now we know about three-phase electricity and direct current.

                    BLDCM, the input is DC, through a filter capacitor to stabilize the voltage. Then it is divided into two routes, one is the use of electric adjustment BEC, the other is the use of red and black lines on the signal line, the other is to intervene in the use of MOS tubes. Here, the electric adjustment is powered up, the microcontroller starts, and drives the MOS tube to make the motor announce the sound of droplets. After startup, some electric adjustments have throttle calibration function. Before entering standby, the position of the throttle will be monitored whether it is high or low or central. When the high telephone enters the calibration of the electric adjustment stroke, the central telephone starts to announce the alarm signal, the motor will drip and drip, and when the low one enters the normal operation condition. When everything is ready, the MCU in the electric regulation will decide the output voltage and frequency concave and convex, and the driving direction and the angle of entry according to the signal on the PWM signal line to drive the speed and steering of the motor. This is the brushless tuning principle. When driving the motor, there are three groups of MOS transistors working in the electric regulation. Each group has two poles, one operates the positive output and one operates the negative output. When the positive output, the negative output does not output, and when the negative output, the positive output does not output. This attitude also forms the communication electricity. Similarly, the three groups work in this way, their frequencies are 8000HZ. Speaking of this, brushless tuning is also equivalent to a frequency converter or perhaps governor used in a factory motor.

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