Research On DC Bus Voltage Stability Control Technology Of AC Drive System

AC drive system has been widely used in many fields such as rail transportation,aerospace and ship power propulsion, as a typical system of modern industry and transportation. With the promotion and implementation of the "13th Five-year Plan", the AC drive system will be more widely used. In this paper, a typical AC transmission system is regarded as the research object, analysis of various causes of transmission system of DC side voltage fluctuation.First of all, this paper introduces the development status of the AC drive system and the main study. The vector control based on field orientation is used in this paper, the mathematical model of induction motor in different coordinate system is obtained and the parameter design method of the double closed loop controller of the control system is given.Secondly, the typical AC drive system is taken as research object in this paper. From the analysis of the typical cascade system of power electronic converter angle, using the modeling method of small signal. The specific impedance expressions of the output impedance and the input impedance of the converter are established by this method, the influence of AC drive system of constant power characteristics on the stability of the system has been analyzed; the root cause of the transmission system of DC side voltage oscillation has been studied. The stability of AC drive system is analyzed by the ESAC criterion, which is simple and effective.Finally, the control strategy of the DC side voltage of the stable AC drive system is studied. The effects of electrical, control and operation parameters of the system on the stability of the DC side voltage stability of the drive system are analyzed, the compensation mechanism for the stability of the DC side voltage is clearly promoted, control strategies based on virtual capacitor and virtual resistance are put forward. The sensitivity function is used to analyze the influence of the control strategy on the dynamic performance of the original system. A large number of stability analyses prove that the control strategies are accurate and effective.In addition, the MATLAB / Simulink simulation is used to build the simulation model of AC drive system. By observing the fluctuation of the system parameters and the changing trend, confirm the correctness of the theoretical analysis and the proposed control strategy is feasible.