Asynchronous Motor Speed Sensorless Vector Control System Research And Design

Asynchronous motor speed sensorless vector control system due to simple structure, low cost of frequency conversion and speed regulation performance of vector control adjustable-speed technology combines is one of the hot topics in electrical systems.This research of main goal is to improve the rotor flux linkage identification methods, accurately estimate the rotor flux, improve the stability of the system under the condition of low speed and the motor under the condition of low speed identification speed; Based on model reference adaptive (MRAS) method to estimate the rotor speed.This paper on the research background, the development of modern AC speed regulation system and speed regulating control strategy is induced and summarized, then analyzing the mathematical model of asynchronous motor, and the principle of coordinate transformation, and detailed discusses the mathematical model of the motor under different coordinate systems; Then the vector control principle, space voltage vector (SVPWM) control algorithm. Subsequently detailed described the improved rotor flux estimation method principle, through the Matlab simulation shows that the improved flux identification method, the simulation model under given low, medium and high speed simulation speed, the flux linkage identification results are comparative analysis, prove that to improve the feasibility and effectiveness of flux linkage model; Based on MRAS method based on the Popov super stability theory making the system asymptotically stable adaptive law is derived, building asynchronous motor speed sensorless vector control system simulation through using Simulink to estimate the rotor speed.Secondly through the Matlab simulation results verify the validity and feasibility of control system. Followed in the construction of the vector control system hardware platform and software system design, this system uses TMS320F2812and Mitsubishi intelligent power module (IPM) PS21867as the control core and inverter at the core of the hardware circuit design, hardware aspects including DSP peripheral circuit, main control circuit, power devices, circuits and DC bus voltage, current sampling circuit design and analysis. Software mainly involves the fixed-point DSP data of Q format and data mark per-unit value processing as well as the overall flow chart of system design, and draw lessons from TI modular programming idea is realized in embedded software development environment of CCS control system, which achieves the function of each module of algorithm.At last, an experimental platform of motor’s static and dynamic performance are tested and analysed in the process of long-term stable operation, debugging the system experimental step by step to validate each module, the module after the validation, starting system debugging, in view of the low speed cases of motor speed identification, the results proved that the identification accuracy and system response quickly, stable, which proves the reliability and feasibility of the system design.