SYSTEM variable speed drive, SYSTEM CONTROL METHOD variable speed drive and a method of cooling the hydrocarbon stream

摘要

1. A method for controlling a drive system with variable speed, comprising an electric motor and a frequency converter disposed between the AC power source and an electric motor, comprising the steps kotoryhpreobrazuyut AC power obtained from the AC power source with a frequency source, the converted power from variable drive frequency which is not equal to said frequency source, the converted power comprises intergarmonicheskie currents having a surcharge nye frequency components intergarmonicheskih frequencies which are not multiples of the frequency source by a factor equal to an integer, is fed to the electric motor converted power, is driven by an electric motor mechanical assembly comprising at least a drive shaft and mechanical strain; cause fluctuations intergarmonicheskih frequency independent the excitation of torsional oscillations in the mechanical assembly and the power source AC toka.2. A method according to Claim. 1, wherein said vibrations applied in accordance with the predetermined configuration kolebaniy.3. A method according to Claim. 1 or 2, wherein said intergarmonicheskih frequency vibrations cause by repeated and periodic changes intergarmonicheskih chastot.4. A method according to Claim. 1, wherein the oscillation frequency of the selected intergarmonicheskoy limit within a maximum deviation of between 3% to 15% of the selected frequency intergarmonicheskoy frequency in the case where said vibrations otsutstvuyut.5. A method according to Claim. 1, wherein said intergarmonicheskih frequency vibrations cause by changing the frequency