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:
Jun. 22, 1999
Filed:
Dec. 17, 1997
Yoriyuki Takekawa, Konan-machi, JP;
Nobukazu Takagi, Konan-machi, JP;
Zexel Corporation, Tokyo, JP;
Abstract
A motor driving apparatus PWM-controls a DC voltage from a rectifying unit according to a rotation speed setting information, and drives a motor by voltage pulse chooped by PWM. The rectifying unit is controlled so that a full-wave rectification is performed when the motor runs at a rotation speed below a prescribed rotation speed and a voltage-doubler rectification is performed when the motor runs at a rotation speed above the prescribed rotation speed. On the other hand, in case a motor drives a compressor of an air-conditioning system, the rectifying unit is controlled so that the full-wave rectification is performed when the air-conditioning system is a cooling operation and the voltage-doubler rectification is performed when the air-conditioning system is a heating operation. When the rectifying unit is controlled for the full-wave rectification, even if a width of voltage pulse given to the motor is decreased, a voltage value of the voltage pulse is half as compared with the voltage-doubler rectification. Hence, since a motor current is small and its current variation is also small, a hysteresis loop due to a variation in magnetic flux becomes small and an iron loss is reduced. When the rectifying unit is controlled for the voltage-doubler rectification, since a DC voltage which is the double of that of the full-wave rictification is supplied, the motor capacity can be increased.