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:
Oct. 29, 2002
Filed:
Jan. 18, 2001
Michael D. Smith, Jefferson City, MO (US);
Thien Q. Tran, Jefferson City, MO (US);
Christopher Douglas Schock, Springfield, MO (US);
James R. Peterson, Fond duLac, WI (US);
Parimalalagan Ramachandran, Ozark, MO (US);
Fasco Industries, Inc., Cassville, MO (US);
Abstract
An apparatus and method for controlling a motor/blower system to provide a constant fluid flow by iteratively loading revised stator frequency values and stator voltage values to a variable frequency drive. Target DC bus current values corresponding to constant fluid flow rates are predetermined and stored as a function of the desired fluid flow rate, the operating frequency, and system specific constants or calculated by the controller as a function thereof during system operation. Actual DC bus current is measured with a current sensor and compared with the target DC bus current. Operating frequency is estimated using a PI controller based on the difference between measured and target DC bus current values. Operating voltage values corresponding to operating frequencies and system specific constants are predetermined and stored in memory or calculated by the controller during system operation. An updated target DC bus current, operating frequency and operating voltage are determined upon each iteration. The updated operating frequency and operating voltage are loaded as control variables to the variable frequency drive upon each iteration.