Dalan Motor shares the control principle and application range of variable frequency motor

What is a variable frequency motor? Dalan Motor tells you that the variable frequency motor actually uses the principle of motor control to control the motor through a so-called inverter. Common variable frequency motors include: three-phase asynchronous motor, DC brushless motor, AC brushless motor and switched reluctance motor. The control principle of the variable frequency motor mainly includes: constant torque control at the base speed, constant power control above the base speed, and weak magnetic control in the ultra high speed range. 1. The base speed 1 generates a counter electromotive force when the motor is running, and the magnitude of the counter electromotive force is usually proportional to the rotational speed. 2 When the motor runs to a certain speed, since the magnitude of the back electromotive force is the same as the applied voltage, the speed at this time is called the base speed. 2. Constant torque control 1 The motor performs constant torque control at the base speed. At this time, the back electromotive force E of the motor is proportional to the rotational speed of the motor. 2 The output power of the motor is proportional to the product of the torque and speed of the motor. Therefore, the motor power is proportional to the speed. 3. Constant power control 1 When the motor exceeds the base speed, the back electromotive force of the motor is kept constant by adjusting the excitation current of the motor, thereby increasing the rotational speed of the motor. 2 The output power of the motor is basically kept constant, but the motor torque is inversely proportional to the speed. 4, weak magnetic control 1 When the motor speed exceeds a certain value, the excitation current has been quite small, basically can not be adjusted, at this time into the weak magnetic control phase. 2 Motor speed control and control is one of the basic technologies of various types of machinery and office and industrial and electrical equipment. 3 With the amazing development of power electronics technology and microelectronic technology, the AC speed regulation mode adopting “special frequency induction induction motor + inverter” is guiding a replacement in the field of speed regulation with its excellent performance and economy. The transformation of the traditional speed control method. 4 to improve the degree of mechanical automation and production efficiency, save energy, improve product qualification rate and product quality, power system capacity, equipment miniaturization, increase comfort, is replacing traditional mechanical speed control with a rapid speed DC speed control scheme. Due to the special nature of the variable frequency power supply and the system's demand for high speed or low speed operation and dynamic speed response, the demanding motor is a demanding requirement, which brings new problems in the electromagnetic, structural and insulation aspects of the motor. . Frequency conversion speed regulation has become the mainstream speed regulation scheme, which can be widely used in continuously variable transmissions of various industries. Especially with the increasing application of frequency converters in the field of industrial control, the use of variable frequency motors is becoming more and more extensive. It can be said that because of the superiority of inverter motors in frequency conversion control compared with ordinary motors, wherever inverters are used, It is not difficult to see the figure of the inverter motor. ----- Responsible Editor: Dalan Oil Pump Motor 02- Purchasing Consultant Copyright http:/(Dalan Motor) Reprint, please indicate the source http://news.chinawj.com.cn