Research On High Voltage Power-saving Control Technology Of 900 KW Dust-removing Fan

In order to achieve the purpose of saving energy and reducing consumption,high voltage power-saving devices with frequency converter have been used in 8 units of 900 kw high voltage fans of Fushun aluminium co.,LTD.Although the converter improves industrial energy-saving efficiency,a large number of harmonics and reactive power are injected into the grid,especially high-power high-voltage inverter.At present,the main methods to solve the problem of power pollution is PWM control technology which is widely introduced into rectifier of high energy-saving equipment,so that unity power factor operation can be finally achieved.In a word,the research on modeling and control of high voltage power-saving rectifier has important application value and theoretical significance.This thesis builds the model of high voltage energy-saving inverter under certain approximate derivation,based on the principle of analyzing the four-quadrant operation of PWM rectifier and the idea of switching function,obtaining the mathematical model in the three-phase stationary coordinate system.In order to solve the problem that there is coupling among neutral current and three phase current in the model of three-phase stationary coordinate system,the paper has introduced the idea of coordinate transformation to transform the model from three-phase stationary coordinate system to two-phase rotating coordinate system which reduces the order of the system,according to the principles of grid voltage vector orientation.For designing the controller by the engineering approach of univariate linear system,the model in two-phase rotating coordinate system has been treated approximately under certain conditions,and ultimately we get the compact four-order linear model,which is prepared for designing the controller.Based on strategy analysis of the control of high voltage energy-saving inverter,we have made the solution that design the structure of the rectifier system into the double closed-loop which is consist of voltage loop and current loop,in order to realize the purpose that the power factor of network side keeps 1 and the voltage of dc side keeps stability,according to the control objectives of both the network and DC sides.Completing the decoupling of the state feedback of current,we design the inner current controller and the outer voltage controller respectively,as well as verifiy the approximate equivalent condition,according to the engineering design methods of making the atypical system typical.Finally,by analyzing the results of Matlab simulation,we have proved that the dynamic indicators of the designed system coincide with the expected targets.For dealing with the problems of DC bus voltage caused by the disturbance of load current,we have introduced the feed-forward compensator to improve the anti-jamming performance of the system,and finally verify the anti-jamming performance by simulating the feed-forward and feedback complex control system.