Title:
DETECTION CIRCUIT OF DC INPUT CURRENT OF INVERTOR
Document Type and Number:
Japanese Patent JPS5583468
Kind Code:
A
Abstract:
PURPOSE:To simplify the constitution and to improve reliability by synthesizing the instantaneous values of detection output of an AC input current detection circuit and a current detection circuit of capacitor. CONSTITUTION:Three-phase AC input is given to the input terminal of a rectifier circuit 10 and further to an invertor 18 via the rectifier circuit 10 and a smoothing circuit 16, then an output frequency and output voltage adjusted to having desired values are given to an electric motor 20. The AC input current of the rectifier 10 is detected by current transformers 22a and 22b and given to one of the input terminal a of a summing amplifier 34 after it has been rectified by a rectifier 24. The charge and discharge current of a capacitor 14 for smoothing voltage is detected by a transformer 30 and given to the other input terminal b of the summing amplifier 34. A semiconductor element which constitutes the invertor 18 can be protected from being charged with excess current by watching the output of the summing amplifier 34.
Inventors:
KURITA SHIGEFUMI
Application Number:
JP15574678A
Publication Date:
June 23, 1980
Filing Date:
December 19, 1978
Export Citation:
Assignee:
FUJI ELECTRIC CO LTD
International Classes:
H02M7/44; H02M7/48; H02M7/537; H02M7/5387; H02P27/06; (IPC1-7): H02M7/44; H02M7/537; H02P13/18