Method and apparatus for operating a converter fed rotating field machine
AssigneeSiemens Aktiengesellschaft
InventorManfred Weibelzahl
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Abstract
An improved method and apparatus for operating a converter fed rotating field machine to obtain better utilization of the converter rectifiers in which the stator windings of the machine are fed with non-sinusoidal phase currents with one phase current always limited to a maximum value and the other phase currents increased by the difference between that maximum value and a typical sinusoidal wave current. This is accomplished in such a manner that the power and torque of the rotating field machine are not affected.
Claims9
A method of operating a converter feeding a three phase rotating field machine having a neutral return line, which machine is normally fed with symmetrical sinusoidal phase currents, the converter being controlled by means of current controls having associated reference value transmitters which form a three phase reference value system, such as to reduce the peak current to which the rectifiers in the converter are subjected comprising generating current reference values which consist of the sinusoidal fundamental of each current with a harmonic superimposed thereon such that one phase current is always reduced to a predetermined maximum value in the central region of a half wave and that at the same time the other two phase currents are increased by a predetermined amount in the outer portion of their half waves.
Apparatus for operating a converter fed three phase rotating field machine having a neutral return line, said rotating field machine being supplied with phase currents generated by converters which are controlled by means of current controls having associated reference value transmitters which form a three phase reference value system, which machine is normally fed with symmetrical sinusoidal phase currents, comprising means for generating current reference values having a waveform with a shape corresponding to the superposition of a sinusoidal fundamental and a harmonic for each phase current such that one phase current is reduced in the central region of the half wave to a predetermined maximum amount and the other two phase currents are increased by a certain amount in the outer parts of their half waves.
Dependencies are inferred from the claim text.