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Patent Searching and Data


Title:
CURRENT DETECTION METHOD OF AC MOTOR
Document Type and Number:
Japanese Patent JP3130440
Kind Code:
B2
Abstract:

PURPOSE: To reduce the influence of current ripple caused bu a PWM voltage by a method wherein, when inverter output currents are sampled, a first phase current is sampled at a timing about a half of the conversion time of an AD converter before the maximum amplitude of a carrier and the order of the sampling of a plurality of phases is changed every time of sampling.
CONSTITUTION: When the output currents of a PWM inverter are sampled, at a timing about a half of the conversion time TCONV before the peak of a carrier, an interruption signal INT is generated and, by a sample-hold signal, a phase-(a) current ia is sample-held and AD-converted and MPU data are taken in. Then the MPU data of a phase-(b) current ib are taken in the same way. When the next interruption signal INT is generated, the order of the sample-hold is changed from phase-(a) and phase-(b) to phase-(b) and phase-(a) by a multiplexer selection signal. With this constitution, the influence of current ripple caused by a PWM voltage is reduced, so that the current control with high precision can be realized.


Inventors:
Momose, Tetsuo
Application Number:
JP1995000034374
Publication Date:
January 31, 2001
Filing Date:
January 31, 1995
Export Citation:
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Assignee:
SANKYO SEIKI MFG CO LTD
International Classes:
H02M7/48; H02P6/06; H02P6/08; H02P6/18; H02P6/182; H02P6/28; (IPC1-7): H02P6/18; H02M7/48
Attorney, Agent or Firm:
後藤 隆英