The Research Of Speed Sensorless Variable-frequency Vector Control System Based On DSP

Speed sensorless variable-frequency vector control system has always been a hot topic inacademic and engineering fields in motor motion control, this paper will be focused on twoaspects of the study:(1) Vector control system based on the BEMF MRAS speed identificationmethod and its implementation, through the analysis of the equivalent circuit of the inductionmotor, equations for back-EMF(BEMF) of induction motor from the stator and rotor sidewere established, through the model reference adaptive principle(MRAS) to estimate thespeed of induction motor.(2) The controller design for the induction motor vector controlsystem. First, establishing the mathematical model of current loop and speed loop, then, giventhe appropriate design methods of the current controller and speed controller.Firstly, in this paper, have a brief review of the history and outlook of the development ofAC drive system, and give a brief introduction to the speed estimation methods for speedsensorless vector control system. Then, in the second chapter, introduces the fundamentalsand principles related to induction motor vector control. The basic equations for inductionmotor, coordinate transformation and mathematical models of induction motor are describedin different coordinates. The basic principles and essence of SVPWM control algorithm ofvector control are detailed described. Taking into account that the modern vector control isrealized by digital control, so the knowledge of digital control is introduced.Nextly, a lot of work is focused on the description of the speed identification methodbased on BEMF MRAS in vector control system, and taking into account of its digitalrealization in the discrete control systems, given Matlab/Simulink simulations andexperimental results. Meanwhile, in order to overcome the traditional drawbacks that rely onengineer’s experience to the PI parameters tuning, adaptive controllers are designed forinduction motor vector control system. We have a detailed description and derivation forcurrent loop PI controller and speed loop PI controller design. Considering the impact ofdigital delay controlling effect in the control system, this paper also discusses the solution,and made the corresponding simulation to verify the effective of the solution. Finally, in the aspect of the software system design, the architecture of system softwaredesign that based on TMS320F28035is given, gives the main program flow and theassociated interrupt program flows and their detailed procedures of induction motor vectorcontrol. The test results are achieved in the relevant test platform, and have a brief descriptionand analysis for the test results observed in Labview.