Study And Implementation Of Speed Sensorless Vecter Control System For Induction Motor

Nowadays, the speed sensorless vector control system of induction motor is one of the hot topics in the field of electric drive system. This paper researched the improved rotor flux identification and the open-loop rotor speed estimation; The algorithm of the motor parameter off-line idetification and the low-speed performance of the system; The algorithm of the S acceleration & deceleration curve and the excitation current adaptive controller.Firstly, the recent development of AC variable speed system and speed control strategy were summarized, the asynchronous multi-variable nonlinear mathematical model and the details of sensorless vector control frequency system principle were introduced, which included the motor mathematical model in different coordinates; The variable frequency vector control theory; the traditional rotor flux model and the improved rotor flux observer; The open-loop speed estimation; SVPWM Algorithm. And then the Matlab simulation of the control system was built to prove this system to be correctness and feasibility.Secondly, the motor parameter off-line identification, the algoruthm of S curve and the design of the excitation current adaptive controller. And then the hardware platform was built and the software system was planned to realized this vector control system. The hardware, which included the design features about DSP, the design and analysis of the main control circuit, fault protection circuit, etc. And the software, which included the software flow chart design of the overall system and the modular program was used in the embedded software development environment CCS to realize each sub-algorithm of the control functions.Finally the static & dynamic performance and the long-term run stability was tested and analysised on the experimental platform to verify the control system which got high torque at low speed, the response of speed and torque in the situation including acceleration & deceleration and different load cases. By adding the exciting current adaptive controller, the static & dynamic performance of the system got more superior and the energy efficiency more evident.