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:
Feb. 02, 1982
Filed:
Apr. 22, 1980
Loren H Walker, Salem, VA (US);
John H Cutler, Roanoke, VA (US);
General Electric Company, Salem, VA (US);
Abstract
A controlled current inverter system forms the basis of an AC motor drive system for furnishing the motor load 18 with a variable frequency, variable magnitude AC current from an inverter 14 which is supplied from a variable DC current source such as a converter 12 by way of a DC link including an inductor 17. Motor speed and torque are controlled through the control of motor current I.sub.M and angle .theta., which is the angle formed between vectors designating motor current and flux through first and second control signal channels 39 and 59 coupled to the DC source 12 and the inverter 14, respectively. A control function of this angle, defined in terms of both method and apparatus, is implemented by means 61 and 63 which limits this angle to predetermined values for relatively low levels of motor current, for example, values of current corresponding to the current required for maintaining a minimum amount of motor flux. Thus, if actual motor current becomes lower than the anticipated motor current, the angle .theta. will be limited in a manner which maintains a minimum motor flux.