Analysis And Design Of Minitype Brushless DC Motors

With the increasing of people’s awareness of energy saving and environmental protection, people pay more and more attention to permanent magnet motors. There are huge numbers of fans in China which consume a lot of electricity power. People pay more and more attention to the energy-saving of fans, and variable-speed energy-saving plays an important role in the field of fans’s energy-saving. The Permanent magnet brushless DC (BLDC) motor can adjust the speed through changing the duty of the cycle, and the circuit of the motor is relatively simple. Besides, the BLDC has the advantage of de-synchronization. So the BLDC motor is is particularly suitable for driving fans.The BLDC motor has some excellent characteristics such as adjusting the speed stepless, high power density, high efficiency and energy-saving, so it is very suitable for fans driving occasions. In order to improve the performance of BLDC motor, it is necessary to study the inhibition of alveolar pulsating technical measures. In this dissertation, the BLDC motor torque ripple suppression is studied and the solution is given and verified by simulation.This dissertation analyzes the design requirements of BLDC motor which used for driving fans by studying the permanent magnetic materials, magnet structure, magnetizing way, winding distribution and pole arc coefficient. This dissertation outlines the structural characteristics of the permanent magnet BLDC motor and the composition of the permanent magnet BLDC motor system, especially focuses on the body of a permanent magnet BLDC, the position detector and electronic switching circuit. This dissertation analyzes the operating principle of the permanent magnet BLDC motor.This dissertation designs a magnet BLDC motor of nN=1450rpm,PN=150W, UN=240VDC. Electromagnetic simulation is done by using Ansys. This dissertation uses one key to generate a finite element model function to generate the motor model into the Maxwell2D finite element interface to have the accurate calculation. Some performances such an no-load flux density, start with a load, steady-state operation of the motor is simulated in the Maxwell2D finite element interface, which provides a basis for the motor design. At last one prototype is made and the performances are tested, and the test results are very close to the simulation results, which proves the accuracy of the electromagnetic design.