Brushless dc motor control structure and superiority of
of brushless dc motor control structure brushless dc motor is a kind of synchronous motor, that is to say, the motor rotor speed of the motor speed rotating magnetic field of the stator and rotor pole (P)F/P. In case the number of rotor fixed, change the frequency of the stator rotating magnetic field can change the speed of the rotor. Brushless dc motor is a synchronous motor with electronic control (Drive), control the frequency of the stator rotating magnetic field and the motor rotor speed feedback to the control center of repeated correction, in order to achieve close to the way the characteristics of dc motor. That is to say, brushless dc motor can be within the rated load when the load changes can still maintain control motor rotor speed. Brushless dc drives including power department and control department as shown in figure (1): power supply provides the three-phase power supply to the motor, motor, power frequency conversion input control department is in accordance with the requirements. Position control. This article from: - the microelectronics netElectronic engineer community the original address: http://www. srvee。 com/indu/apply/zlwsdjkzjg_55496。 The HTML brushless dc motor power supply can be directly to dc input (Generally for 24 v)Or in an alternating current input (110V/220 V)Will have to the first, if the input is an alternating current converter (converter)Converted to dc. Both input dc or ac input to turn to motor coil must be before the dc voltage by the inverter (inverter)Into three phase voltage to drive motor. Brushless dc motor inverter (inverter)By six power transistor (commonlyQ1～Q6)Divided into the upper arm (Q1和Q3, Q5)/ lower arm,Q2、Q4、Q6)Connected to the motor as control flows through the motor coil switch. Brushless dc motor control department provides PWM (Pulse width modulation)Decision power transistor switching frequency and the inverter (inverter)The timing of the commutation. Brushless dc motor is generally want to use in the speed can be stable in value when the load changes will not change speed control, so the motor can be induced magnetic field of hall sensor mounted inside (大厅-传感器)As the speed closed loop control, and at the same time as the basis of phase sequence control. But that is only used as a speed control and is not to be used as a set of
the advantages of brushless dc motor dc motor has a rapid response, large starting torque, rotating speed of from zero to rated speed can provide the rated torque performance, but the advantages of the brushless dc motor is also its drawback, because of the brushless dc motor to produce a constant torque under the rated load performance, the armature magnetic field and rotor magnetic field must be constant to maintain 90 & deg; This is about to borrow from the carbon brush and commutator. Carbon brush and commutator motor rotation would produce sparks, carbon powder, so besides can cause damage of components, its usage is restricted. Ac motor without carbon brush and commutator, free maintenance, strong, wide application, but if characteristics to achieve equivalent to the performance of the brushless dc motor must use complex control technology to achieve. Nowadays the rapid development of the semiconductor component switching power frequency to speed up the many, improve the performance of the drive motor. Microprocessor is also more and more fast, which can realize the two ac motor control on a turning shaft in the rectangular coordinates system, appropriate control of ac motor current component in two axis, similar to dc motor control and the performance of the dc motor is quite. Also has a lot of microprocessor control motor required functionality in the chip, and volume smaller and smaller; As analog/digital converter (模拟,-数字转换器ADC)And pulse width modulation (脉宽调制器,PWM)…And so on. Brushless dc motor which is electrically control ac motor commutation and similar institutions brushless dc motor characteristics and without dc motor on the lack of an application.
