Vector control principle: imitating the control principle of DC motor, according to the dynamic mathematical model of asynchronous motor, the stator current vector is decomposed into excitation component and torque component through a series of coordinate transformation.

The torque current component and excitation component of the motor are controlled separately, and the magnetic field and torque are decoupled after the rotor magnetic field is oriented, so as to control the torque of the asynchronous motor and make the asynchronous motor obtain the control performance close to that of the separately excited DC motor. ?

Extended data

Using vector control, AC induction motors and synchronous motors can be controlled in a manner similar to separately excited DC motors. In separately excited DC motor, the magnetic field current and armature current can be controlled independently. In vector control, the magnetic field and armature current are perpendicular to each other, so they will not affect each other in theory. Therefore, when controlling the torque, the flux linkage of the magnetic field will not be affected, so it can have a fast torque response.

Vector control will generate three-phase PWM voltage to the motor according to the current vector calculated in the program to control the three-phase current of the motor. Among them, physical quantities such as current and voltage will be converted between two systems, one is a three-phase system that changes with speed and time, and the other is a two-axis nonlinear rotating coordinate system. ?

way

The general frequency converter with vector control mode can not only match the DC motor in the speed range, but also control the torque generated by the asynchronous motor. Because the vector control mode is based on the accurate parameters of the controlled asynchronous motor, some general frequency converters need to input the parameters of the asynchronous motor accurately, and some general frequency converters need to use speed sensors and encoders.

In view of the fact that the motor parameters may change, thus affecting the control performance of the inverter to the motor, the relevant parameters in the control algorithm are adjusted according to the identification results, so that the common asynchronous motor can be effectively vector controlled.

Baidu encyclopedia-vector control

Baidu Encyclopedia-Torque Vector Control