Patent ID: 7471525
Filing Date: 2008-12-30
Classification: H02M

Abstract:
1. A converter comprising a converter circuit, where the converter circuit comprises a plurality of bridge-connected semiconductor switching devices for converting AC power into DC power, a smoothing condenser connected in parallel to DC side of the converter circuit, a condenser current detector provided in a condenser circuit to detect a condenser current flowing through the smoothing condenser, and a controller for controlling the condenser current to be a set value, wherein said controller comprises a q-axis current controller which controls a q-axis current component of DC output of said converter circuit to reduce a difference between the detected condenser current and the set value, a DC current detector for detecting a DC current of said converter circuit, and wherein said controller for controlling the condenser current includes a calculator which calculates an AC current on input side of said converter circuit on the basis of said DC current and operation states of said plurality of semiconductor switching devices and a compensator which calculates a q-axis current component of said AC current to correct a q-axis current command value on the basis of said calculated q-axis current component.