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. 30, 1995
Filed:
Jan. 14, 1993
Pradeep K Sood, St. Louis, MO (US);
james L Skinner, Florissant, MO (US);
Douglas M Petty, Clayton, MO (US);
Emerson Electric Co., St. Louis, MO (US);
Abstract
A dynamoelectric machine, for example, a brushless permanent magnet motor (M) has a plurality of stator windings (S) and a rotor (T) which rotates with respect to the windings. Apparatus (10) is provided for controlling winding commutation with respect to the rotor. A DC bus (14) supplies current to the windings. The current waveshape has characteristics which are a function of the commutation angle with respect to the windings. Current magnitude and waveshape are sensed by a sensing unit (22) and the sensed waveshape is sampled to obtain commutation information. An inverter (20) successively energizes and de-energizes the respective stator windings. A controller (26) obtains samples of the waveshape, and processes the information obtained by the sampling to control winding commutation. The controller controls the inverter operation to provide a commutation angle which optimizes motor performance and efficiency for a particular set of motor operating conditions. To do this, the processor evaluates slope and amplitude information from the sampled DC bus current waveshape, determines if the waveshape corresponds to a desired waveshape representing a desired commutation angle, and adjusts the commutation frequency produced by the inverter, if necessary, to obtain the desired waveshape.