Frequency converter for AC motor
First Claim
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1. A frequency converter for an asynchronous motor comprising:
- a voltage converter including switches provided therein;
a DC bus including a shunt provided therein;
a control circuit; and
a processing circuit;
wherein the switches of the voltage converter are controlled by the control circuit and are powered by the DC bus and the shunt measures DC current passing on the bus; and
wherein the processing circuit calculates, when at least one of two components of an output voltage vector is less than a predetermined value, a first vector having each of two components thereof at least equal to the predetermined value, and calculates a second vector, wherein a vectorial average of the first and second vectors is equal to the output voltage vector.
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Abstract
A frequency converter for an asynchronous motor including a voltage converter (O) equipped with switches (Sa, Sb, Sc) controlled by a control circuit (CC) and powered by a DC bus (B) on which a shunt (Sh) is installed to measure a DC current passing through the bus, wherein, when at least one of two components of an output voltage vector Vs is less than a predetermined value TMIN, the frequency converter includes a device which calculates firstly a vector Vs'"'"' each of two components thereof being at least equal to the predetermined value TMIN, and secondly a vector Vs" such that vectorial average of Vs'"'"' and Vs" is equal to the output vector Vs.
41 Citations
6 Claims
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1. A frequency converter for an asynchronous motor comprising:
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a voltage converter including switches provided therein; a DC bus including a shunt provided therein; a control circuit; and a processing circuit; wherein the switches of the voltage converter are controlled by the control circuit and are powered by the DC bus and the shunt measures DC current passing on the bus; and wherein the processing circuit calculates, when at least one of two components of an output voltage vector is less than a predetermined value, a first vector having each of two components thereof at least equal to the predetermined value, and calculates a second vector, wherein a vectorial average of the first and second vectors is equal to the output voltage vector. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification