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:
Sep. 05, 1995
Filed:
Mar. 18, 1994
North Carolina State University, Raleigh, NC (US);
Abstract
The present invention relates to a method and apparatus for controlling the speed of an electronically commutated motor. Such motors typically include a rotor, a stator coil, and an electronic commutator for controlling electrical power flow from an electrical power source of predetermined frequency to the stator coil. The invention includes the steps of generating a switch control signal responsive to a position of the rotor; generating a phase gating signal from the electrical power source of predetermined frequency, the phase gating signal having twice the predetermined frequency and having transitions in timed relation to the zero crossings of the electrical power source; varying the timed relation of the phase gating signal in accordance with an operational parameter desired for the electronically commutated motor; generating a phase controlled switch signal which is responsive to the phase gating signal and the switch control signals; and applying the phase controlled switch signal to the electronic commutator to control the electronic commutator, thereby controlling the speed of the electronically commutated motor.