Title:
MOTOR DRIVING METHOD AND ELECTRIC APPARATUS
Document Type and Number:
Japanese Patent JP3419157
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To slowly reduce the current in a first phase driving coil and thus reduce noise by, even after the first transistor in a second half-bridge circuit is made to form its current path, making the first transistor in a first half-bridge circuit interrupt, form and re-interrupt its current path.
SOLUTION: When the energized phase of a three-phase bridge circuit is switched, an upper arm switching element 25 in phase V that switches from the unenergized phase to the energized phase, for example, is kept energized, and further an upper arm switching element 23 in phase U that switches from the energized phase to the unenergized phase is turned on and off according to any duration of energization. Meanwhile, a lower arm switching element 28 in phase W is PWM-controlled. Thus phases U, V and W are sequentially subjected to sustained energization, PWM control and energization duration control, and soft switching is thereby accomplished to make gentle the rise and fall of the phase currents when the energized phase is switched. This makes it possible to reduce noises from a sensorless brushless motor.
Inventors:
Masatoshi Morikawa
Kunio Seki
Yasuhiko Kougami
Kunio Seki
Yasuhiko Kougami
Application Number:
JP18382495A
Publication Date:
June 23, 2003
Filing Date:
July 20, 1995
Export Citation:
Assignee:
株式会社日立製作所
International Classes:
H02P6/06; H02P6/08; H02P6/17; H02P6/182; H02P6/28; (IPC1-7): H02P6/06
Domestic Patent References:
| JP5316784A | ||||
| JP4368491A |
Attorney, Agent or Firm:
Yasuo Sakuta
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