Main Circuit Design And Harmonics Suppression In High Power DC Drive Control System

With the rapid development of steel pipe industry in recent year, the demand of domestic seamless steel pipe rises from 4189 thousand tons to 13030 thousand tons, rises 2 times from 2000 to 2006. Many pipe plants establish new projects, and some plants renovate and upgrade old production line. In this paper, the design of main circuit and harmonics suppression of tube rolling mill is introduced which is the most important part in seamless steel pipe production line.In this paper, the main circuit is designed in high power DC drive control system of the ASSEL tube rolling mill in the Tianjin Seamless 140 production line. The harmonic effects of ASSEL mill system to grid is introduced, the principle of high power DC drive control system,12-phase pulse rectifier system , and how to select the components of the main circuit and so on is analysed. The results of simulation show that 12-phase pulse rectifier system with equilibrium reactor will markedly improve the harmonic content and has broad prospects and important value.At the beginning of the paper, the general development situation of high power DC drive control system is introduced, the development trends and latest fruits at home and abroad of harmonics suppression in high power DC drive control system, and present the hot points in this field and research contents is generalized. In learning and mastering high-power DC drive control principle counters, based in Tianjin Seamless 140 ASSEL mill as an example,the main circuit of the high-power DC drive control system is designed.Second the article has a detailed study to harmonic analysis and suppression program of the high-power DC drive counters and proposes the suppression plan. The harmonic effect of ASSEL mill system to grid is introduced, and the principle of high power DC drive control system,12-phase pulse rectifier system, equilibrium reactor and how to select the components of the main circuit is analyzed. Also in the paper, the harmonic suppression of process channel,field meters,power capacity expansion in converters and so on is introduced.In addition, by using MATLAB 7.0 Simulink and Simpowersystems Software, the paper first selects motor Z710-500 as a target simulation, then has a simulation to the 12-phase pulse rectifier circuit control system with reactor,simulation results show that the system can reduce the waveform distortion and make the DC output voltage stable,and moreover the equilibrium reactor can keep the loads of two sets of rectifying bridge equilibrium. At last, the paper has a simulation to the system which combines the 12-pulse rectifier circuit and 11,13 times passive filter ,the result shows that the system can suppress 5,7 times harmonic component ,and can effectively reduce the 11,13 times harmonic component.Finally, the shortcomings and requisite amelioration of the high power DC drive control system and proposes the future work is concluded in the thesis.