Dissertation > Industrial Technology > Electrotechnical > Motor > General issues > Motor test,run

Load commutation frequency conversion technology in the application of high voltage motor starting

Author ZhangHongLe
Tutor HuTianYouï¼›HouMinJie
School University of Electronic Science and Technology
Course Mechanical Engineering
Keywords Synchronous motor Load commutation Soft Start System
Type Master's thesis
Year 2009
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High-power synchronous motors are widely used in metallurgy, iron and steel, petrochemical and other industries. However, the synchronous motor starter has been a very complex issue, which has long been the starting mode is an important topic of concern. High-power synchronous motor starting mode is usually used: direct full voltage starting, series reactor voltage starting, variable frequency start, etc., which is the best way to start conversion start. The use of high-voltage power unit starts rotating frequency synchronous motor, can effectively reduce the starting current, reducing start-shocks. However, the rotation frequency range of unit equipment, complex structure, stations and vast, noisy, high maintenance costs, so the technology is gradually phased out. With the power electronics, microelectronics, automatic control theory, computer technology and advanced manufacturing technology continues to evolve, the electrical drive technology has undergone a historic revolution that replaces AC variable speed DC drive, computer numerical control technology to replace analog control technology. AC still widely used in high-voltage power inverter start synchronous motor starting fields. Of the unit is simulated altitude aircraft engine test cell large gas source center, which has 10 units 10kV, 12000kW synchronous motor and four 10kV, 5000kW induction motor. Which, 12000kW synchronous motor with rotating frequency conversion unit starts. Rotation frequency unit mainly consists of a synchronous motor, two DC generators, two DC motors and a synchronous generator form; output range is 0.8HZ ~ 50HZ, 200V ~ 10.5kV, 4000kW; excitation by changing the DC generator Synchronous generator output current changes the frequency and voltage. Start 12000kW synchronous motor, the frequency of about 0.8HZ, the starting current is less than 300A (40% of the rated current); single motor from start to synchronize the grid for about 6 minutes. Low degree of automation of the system. Needs of the unit where the new gas source plant consists of three air compressors form (using 10kV, 15000kW synchronous motor drag), so need to design a frequency soft start system, in order, starting three compressors require inrush current is small start time is short, and the Power Grid. Through technical analysis, chose SIMENS company LCI inverter load commutation frequency soft start system constitutes the hope that through the system design, in mastering the load commutation inverter working principle and performance, based on the frequency of future plant operation maintenance accumulated technical experience. Through the project's design research work to improve the current altitude simulation test stand automation level of gas supply systems, and establish a corresponding frequency soft start technology specification for future gas supply system for the further development and providing technical reserves.

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