Is inserted in output current method of detection in the output current method of detection of three phase circuit

摘要

PROBLEM TO BE SOLVED: To provide a method and a device for detecting the output current of a three-phase PWM inverter, where a current equivalent to three-phases is detected from a DC current which is detected by a current detector of a DC bus line, which is used for controlling or protecting the inverter.;SOLUTION: A three-phase PWM inverter device comprises a current detector 4 inserted in the DC bus line, and outputs a three-phase voltage by PWM driving a switching element of an inverter 1. It also comprises a switching pattern calculating means 6 for calculating a prescribed PWM switching pattern based on a voltage command, and a phase current converting means 8 which performs phase current conversion with the DC bus line current detected with the current detector 4 based on the PWM switching pattern. Thus, the current in each phase of three phases is surely detected with no additional circuit, with even detection errors among three phases.;COPYRIGHT: (C)2005,JPO&NCIPI