The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 28, 2000
Filed:
Mar. 09, 1998
Fuji Electric Co., Ltd., , JP;
Abstract
A variable speed driving apparatus drives a plurality of induction machines that facilitates reducing the deviations of the primary magnetic fluxes of the induction machines from the reference and preventing the torque and rotating speed of each induction machine from lowering in the low speed range or when the loads on the respective induction machines are unbalanced. The variable speed driving apparatus includes an inverter 1, induction machines 2, current detectors 3, speed detectors 4, a reference angular frequency operating device 6 for operating the rotating angular frequency of the induction machine bearing the heaviest load based on the output signals of the speed detectors 4, a first phase difference operating device 7.sub.1, for operating the first phase difference between the secondary side component of a reference current and a primary reference magnetic flux, a first reference slip angular frequency operating device 8.sub.1 , to which the first phase difference is inputted, an adder 12.sub.1, for adding the output of the operating device 8.sub.1, and the output of the operating device 6, an integrator 13 for integrating the output of the adder 12.sub.1, a detected current vector rotating device 5 for converting the output of the current detectors 3 to a q-axis component and a d-axis component based on the output of the integrator 13, a q-axis current regulator 10, a d-axis current regulator 11, and a reference voltage vector rotating device 15.sub.1 for converting the reference d-axis current value and reference q-axis current value to reference three-phase voltage values based on the output of the integrator 13.