Research On The Intelligent Starter And Stoper System Of Asynchronous Motor In Large Pump Station

Although tradictional starters,such as star delta starter， step-down starter ofseries connection with resistance or frequency sensitive rheostat， has reduced theimpact of starter current to some extent,these starting methods can be directly madeinto implement solely relay on contactor switch, which is susceptical to lead tofrequency change of voltage and current.This means that the influence to grid oftraditional starting methods can not be absolutely eliminated,and it can also contributeto secondary impact on equipment. Therefore,the traditional start.stop methods ofasynchronous motor cannot satisfy the new demand for the development ofagriculture,and it is particularly important to improve the traditional startingtechnology.New intelligent soft starter can not only contribute to reduce the startingcurrent of motor and the impact to the grid,but aslo effectively eliminate thephenomenon of "water hammer"of the pump,reduce the torque ripple and energyconsumption, improve the quality of power grid, make the pumping station intointeligent,informatization and digitization.The adoption of new intelligent soft star.stop technology in the upgrading of largepumping stations has become a trend.This paper is connected with the project ofpumping station renovation, discusses appliction of the intelligent soft starter inpumping station renovation and its advantages.This paper mainly introduces theelectronic soft starter based on pump load and hierarchical variable frequency soft starttechnology principle, starting mode, operation mode and control methods andimplementation.Firstly,the paper expounds present situation of the engineering application of motorstart.stop technology in pump station, the electronic soft starter and grading applicationsituation and the development trend of hierarchical frequency softstarter;secondly,analysis and discussion associated to the electronic soft start principle has been thorough carried on,modeling simulation comparison and analysis betweendirectly starting and slope voltage electronic soft starting has been carried.Thirdly,theprinciple of variable frequency soft start modeling and simulation has beensystematically expounded, and the methods comparion between the electronic slopesoft start andvariable frequency soft start have been carried on, based on which thecauses of the torque ripple has been disscussed, and a control method based on thepower factor Angle closed.loop control was proposed for ripple suppression;Thenharmonic analysis of electronic soft starter and hierarchical variable frequency softstart with the Fourier transform is presented.Finally,the control method based on adaptive fuzzy PID is proposed, and thestability and robustness of fuzzy control is verified by the experiment.What is more,the intelligent design of hardware and software of the control system is completed, andanalysis is given combining with experiment.