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:
May. 26, 1998
Filed:
Jan. 17, 1997
John F Farrow, Plymouth, MI (US);
Medar, Inc., Farmington Hills, MI (US);
Abstract
A method and system for controlling the output current of large, low-voltage, DC power supply which includes at least one transformer primary by controllably switching an AC power line voltage to the primary as a function of actual and desired output currents. SCRs are used to switch, using phase control, the AC primary voltage to the transformer(s) of the power supply in order to control the output current. Given the incoming power line voltage, the current value from the previous power line cycle and the desired current for the present cycle, the function is used to find the SCR firing angle to attain the desired output current in the present power line cycle. Actual measurements of output current and power line voltage are used to modify the function to reflect changes in power line voltage and/or circuit impedance to obtain a modified function. Preferably, instantaneous changes in power line voltage are measured and used to change the input variables to the function in order to provide instantaneous corrections for power line voltage changes. Diagnostic information concerning the operation of the DC power supply is determined from the modified function.