Measurement of the current of a frequency converter
AssigneeVacon Oyj
InventorsRisto Komulainen, Hannu Saren, Jaakko Ollila
Life of this patent
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Abstract
A method and an apparatus for measuring the output currents of a frequency converter, preferably a vector-controlled frequency converter, which comprises a mains bridge (10) connectable to an alternating-current network and a load bridge (11) connectable to an alternating-current load and between these a direct-voltage intermediate circuit, by using current samples obtained from a current measuring sensor in the intermediate voltage circuit, wherein a sample is taken from the signal of the current measuring sensor substantially simultaneously with a point of change of the output voltage vector and upon the lapse of a predetermined delay after the point of change after the switching effects have settled.
Claims20
A method of measuring the output currents of a vector-controlled frequency converter comprising a mains bridge connectable to an alternating-current network and a load bridge connectable to an alternating-current load and between these a direct-voltage intermediate circuit, by using current samples obtained from a current measuring sensor disposed in the intermediate voltage circuit,
- wherein a sample is taken from a signal of the current measuring sensor substantially simultaneously with a point of change of an output voltage vector and upon the lapse of a predetermined delay after the point of change after switching effects have settled.
An apparatus for measuring the output currents of a frequency converter, preferably a vector-controlled frequency converter comprising a mains bridge connectable to an alternating-current network and a load bridge connectable to an alternating-current load and between these a direct-voltage intermediate circuit, said apparatus comprising a current measuring sensor in the intermediate voltage circuit and a control system for determining output currents by using current samples obtained from the current measuring sensor, and for taking a sample from a signal of the current measuring sensor just before each point of change of an output voltage vector and after each point of change after switching effects have settled.
Dependencies are inferred from the claim text.