| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and a method for detecting current, capable of obtaining accurate phase current information by eliminating DC components included in the output of a waveform detector including a current transformer. SOLUTION: The waveform detector includes at least a current transformer for detecting a phase-current waveform of a permanent magnet motor supplied with a dummy AC voltage generated by on/off control of a plurality of semiconductor switching devices of which respective reflux diodes are connected in reversely parallel, there is provided with a voltage fluctuation detecting means for detecting voltage fluctuations of the phase of an object subjected to waveform detection; a signal-holding means for holding the detected value of the waveform detector at a voltage fluctuation timing detected by the voltage fluctuation detecting means during on-duration of the semiconductor switching devices, associated with the phase of the object to be subjected to waveform detection; and a signal waveform correcting means for correcting an output signal waveform of the waveform detector by the detected value held by the signal-holding means. |
