The key to the application of vector control technology mainly includes accurate motor parameter determination, appropriate coordinate transformation, accurate current control, high-performance speed detection and advanced control algorithm, etc., the following is a specific introduction: Accurate motor parameter measurement of parameters such as stator resistance and rotor resistance, inductance, inductance, mutual inductance and rotor stator logarithmic, etc., are the basis of vector control algorithm. The accuracy of these parameters directly affects the control effect. Generally, the motor parameters can be accurately determined by no-load test, short circuit test and other methods, and the automatic parameter identification function of the inverter can be used to automatically detect and calculate the relevant parameters before the motor is run. Appropriate coordinate transformation of vector control needs to be under the three-phase static coordinate system of physical quantity into two phase rotating coordinate system analysis and control, commonly used coordinate transformation have Clarke transform (Clarke transform) and parker transform (Park transformation). Through appropriate coordinatetransformation, the complex model of AC motor can be simplified to a model similar to DC motor, so as to achieve independent control of motor flux and torque. In practical application, it is necessary to choose the appropriate coordinate transformation mode according to the type of motor, control requirements and system characteristics, and ensure the accuracy and stability of the transformation process.

Precision of current control in vector control, the stator current is decomposed into excitation current and torque current, need precise control

on the two current component. The current closed-loop control strategy is usually adopted. By comparing the given current and the actual detected current, the PI regulator and other control algorithms are used to generate control signals to adjust the output voltage of the inverter, so that the actual current tracks the given current. The precision of current control directly affects the torque control precision and dynamic performance of motor, so it is necessary to use high-performance current detection circuit and fast control algorithm to achieve accurate current tracking and regulation. High speed detection in order to achieve the good effect of vector control, especially in need of precise speed control applications, the accurate speed detection is very important. The commonly used speed detection methods include photoelectric encoder, rotary transformer and other hardware detection methods, and speed sensorless detection methods based on motor models. The hardware detection method has high precision, but the cost is high and the installation and maintenance is relatively complicated. The speed sensorless detection method has low cost and high reliability, but the algorithm is complex and the accuracy is affected by the motor parameter change and noise. Selecting a suitable speed detection method and ensuring the accuracy and real-time performance of the speed detection is one of the keys to apply vector control technology. Advanced control algorithm of advanced control algorithm is the core of the high performance vector control. In addition to the traditional PI control algorithm, intelligent control algorithms such as predictive control, fuzzy control and neural network control can also be used. These algorithms can better deal with the nonlinear, time-varying and uncertain problems of the motor, and improve the robustness and dynamic performance of the system. For example, predictive control can predict the future output based on the model and current state of the motor and adjust the control strategy in advance to achieve faster and more accurate control.