Patent ID: 6693406
Filing Date: 2004-02-17
Classification: B60H,F25B,Y02T

Abstract:
A method of controlling an electric motor by regulating at least a current Iout, a voltage Uout and a frequency fout to an input of said motor, where the number of revolutions for said electric motor is proportional to said frequency fout, comprising the steps of:if an available power Pin from an energy source provided in purpose of driving said electric motor is larger than or equal to the nominal desired power Pnom for said electric motor, the current Iout, the voltage Uout and the frequency fout are set to corresponding nominal values Inom, Unom and fnom respectively, to obtain said desired power Pnom and desired frequency fnom; if said available power Pin is less than said desired power Pnom, Uout and fout are reduced, such that the ratio between Uout and fout is substantially constant during that Iout is kept equal to Inom.