Title:
DETECTION METHOD FOR ELEMENT CURRENT ON VOLTAGE-TYPE PULSE WIDTH MODULATION-SYSTEM CONVERSION DEVICE
Document Type and Number:
Japanese Patent JPS56132173
Kind Code:
A
Abstract:
PURPOSE:To make possible use of any element of proper capacity by inputting an AC output current and a voltage command signal to an element current detector consisting of a multiplier and an adder and detecting currents on a thyrister and a diode separately. CONSTITUTION:An output from a converter 12 with plural thyristers and diodes connected in antiparallel and a voltage command signal obtained from a frequency command circuit 32 through a multiplier 26 are input to an element current detector 28. Then the first signal proportional to an output current and the second signal which is a product of a signal proportional to the first signal and a converter output voltage and a signal 3 being a function of a phase difference between an output voltage and an output current are processed by the detector 28 at a prearranged ratio under an addition a subtraction formula. Consequently it is possible to detect electric currents flowing through a thyrister and a diode separately, so that cost can be reduced by properly setting the capacity of each element.
Inventors:
OKUYAMA TOSHIAKI
Application Number:
JP3409980A
Publication Date:
October 16, 1981
Filing Date:
March 19, 1980
Export Citation:
Assignee:
HITACHI LTD
International Classes:
H02P27/08; H02M7/48; H03K7/08; (IPC1-7): H02P7/62; H03K7/08