Simulation Researchs Of Asynchronism Machine Speed-Governing System And UPFC

This paper simulates the asynchronism machine speed-governing system and UPFC.It builds the simulation model based on analyzing mathematics model, and draw the conclusion. This paper introduces the development of AC electric drive technology and UPFC, analyzing the main control methods, ultimate composition and operating principle of electromotor frequency-variable and speed-governing technology. It researches the asynchronous machine frequency-variable and speed-governing system based on SPWM, and asynchronous machine vector control system based on coordinate conversion and magnetic field orientation. It analyses the basic priciple and control strategy, and researching the influence of UPFC improving quality of power supply.This paper analyses mechanical and V/F contral characteristic of asynchronous machine frequency-variable control, and reasarches SPWM. It researches vector control system of asynchronous machine, which bases on coordinate conversion and magnetic field orientation. It conceives the models of above two modulating methods on MATLAB/SIMULINK, and it analyses the result of simulation, then compares the two simulations. The result of simulation indicates that if we adopt SPWM variable frequency and speed regulation, it makes the motor run under sine wave approximately, and the rebound of torque will be smallest, it also has good characteristic of speed regulating. Because the field current is const, controlling the torque current will be the same with controlling electromagnetic torque. The vector control system performers as well as DC machine on speed regulating, and it is excellent control mode. SPWM variable frequency and speed regulation is the popular control method, but the vector control system is the efficient AC control system, it will be the future fashion because of its superiority speed regulating.The paper researchs the influence of UPFC improving quality of power supply. It builds UPFC simulation model useing SIMULINK of Matlab based on UPFC basic principle and contral strategy,analysing the connection of system harmonic and UPFC.The result of simulation indicates that UPFC dynamic model and control system are right,and it can improve the stability of system steady state and transient state, restrain system higher harmonic, and improve steady state quality of power supply.