DC cooling fans are very common in our lives. So what is a variable frequency motor? Is it closely related to the cooling fan
The frequency conversion motor has the characteristics of a DC motor, but uses an AC motor structure. That is to say, although the external power is direct current, but DC AC frequency conversion control technology is purchased, the motor body works completely according to the principle of AC. Therefore, the variable frequency motor is also called "self-controlled variable frequency synchronous motor". The speed n of the motor depends on the set frequency f of the controller.
The drive circuit of the variable frequency motor consists of two parts: the main circuit and the control circuit. Now these two parts have been integrated into the same chip, so that all control functions of the variable frequency motor can be implemented with only one device, simplifying the circuit structure. As the industry pays more attention to energy saving and noise suppression, many industrial products tend to use brushless motors, which places higher requirements on motor microcontrollers. As a new generation of motor control digital signal processor chip, the cost-effective TMS320C240 is very suitable for this task.
The three-phase star connection of the DC cooling fan is connected with a frequency conversion motor control circuit. The DC power supply supplies power to the three windings of the motor in a time-sharing manner through a three-phase frequency conversion circuit composed of a metal oxide semiconductor tube. At each moment, only one of the three pairs of windings passes current to generate a magnetic field, and then stops supplying power to the pair of windings and powers the adjacent pair of windings, so that the magnetic field axis in the stator rotates 120 degrees in space Under the effect of magnetic force, the rotor rotates 120 degrees following the stator magnetic field. When a voltage is sequentially applied to A, A, C, B, C, B, A, C, A, C, B-, a rotating magnetic field is formed in the stator, so the motor continuously rotates.
Cooling fan experts know that as long as we disassemble the DC cooling fan
motor, we can see that the DC cooling fan uses a variable frequency motor, which can be identified from the position of the coil. Frequency conversion motor control circuit board, control chip will integrate digital signal processor function and drive instrument, simplify circuit structure. The speed of the motor can be changed by programming the control chip.
Shenzhen Jiangshanlai Electronics Technology Co., Ltd. was established in 2005. Located in Shenzhen, China, is a professional manufacturer of DC brushless motors, DC cooling fans, DC brushless fans, DC bracket fans, booster cooling fans, mini cooling fans, DC cooling fans, DC fans, non-standard fans, R & D and manufacturing , Sales, and service.