| Braking is the key problem of large pumped storage motors. With the deve-lopment of large pumped storage power station, the research is more and moreimportant, which is about braking of pumped storage motor. The braking of staticfrequency converter is an effective way, it has a great development prospect.The relationship of loss, which cost kinetic energy of pumped storage machine,and the speed of the rotor is given in the thesis. The simulation software of electricalbraking mode based on MATLAB/GUI is built. The detailed analysis and calculationof braking process which of static frequency converter is done by using the simu-lation software, the curves of speed in the different conditions are also given.The detailed analysis and calculation of the process, which is of stator threeshort circuit braking is also done by using the simulation software. The curves ofspeed in the different conditions are also given. The best scheme is analyzed. Thebraking of static frequency converter and stator three short circuit is compared, inorder to optimize braking scheme.The problem that converter is can’t be directly used for fast starting, brakingand frequently positive and negative control occasions. A kind of energy feedbacksystem of inverter is designed. The mathematical model of inverter energy feedbacksystem is also established. The current control mode, which of triangle wave issimulated and calculated. The change rule, which of feedback current in the processof energy feedback system is analyzed. The influence of band time and lowharmonics for feedback current is also concluded.The conclusion written in this thesis delivers a reference for the design, which isabout braking of static frequency converter of pumped storage machine. It hastheoretical significance and practical value. |
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