The Experimental Research Of Asynchronous Motor Vector Control System Based On DSP

With the improvement of the manufacturing level of power electronic devices and the continuous improvement of control theory,based on the vector control of asynchronous motors,the AC speed control technology driven by IGBT has gradually replaced the trend of DC speed control technology.However,there are still many technical details that need to be further improved when AC speed control is implemented.There are still many problems to be studied in the application of advanced control theory.In this paper,the special DSP chip for motor control is taken as the control core,and the AC speed regulation experiment is practiced,and some key technologies are studied in depth.In order to achieve accurate vector control,it is necessary to increase the real-time measurement of the three-phase stator side voltage and the DC bus voltage.In this paper,a voltage detection circuit with isolation function is designed based on high-precision linear analog optocoupler and packaged on a 15×32mm PCB.The voltage detection accuracy can reach ±1%.Compared with the traditional Hall element isolation amplifier voltage detection has the advantages of small size,low price,high linearity.During the power-up of the main circuit rectification part,various methods have been studied in this paper for how to cut off the charging resistance.Directly using the hardware in the power-up process to set the delay circuit is currently the main form of use,in this regard there are many patents for inventions.This article independently designed an adjustable delay pre-charging circuit that can accurately complete the short-circuit of the charging resistor when the bus voltage is more than 85% charged.When the traditional PI regulator is used as the vector control system controller,the tracking curve of the speed and flux linkage is over-modulated,and the system performance is easily affected by the motor parameters.Therefore,in order to eliminate the overshoot and improve the robustness and anti-interference of the system,this paper proposes to add variable-speed integral control to the flux linkage regulator and introduce an adaptive integral sliding mode surface variable structure control for the speed regulator.The simulation experiment proves the system.The speed regulation performance has been significantly improved.In addition,on the hardware circuit platform of the vector control system of the asynchronous motor built by ourselves,a large number of experimental studies on different modulation methods such as SPWM,SVPWM,and synchronous modulation and asynchronous modulation are performed.The open-loop VVVF speed regulation experiment is completed on the hardware platform.