Title:
BRAKING METHOD FOR VARIABLE SPEED AC MOTOR
Document Type and Number:
Japanese Patent JPS58127580
Kind Code:
A
Abstract:
PURPOSE:To interrupt zero current which does not shorten the lifetime of the contact of a main circuit breaker by raising a field voltage to equalize the counterelectromotive force of an AC motor to the output voltage of a VVVF (variable voltage variable frequency) inverter, and then opening a main circuit breaker, thereby generatively braking. CONSTITUTION:The phase difference delta between the output voltage VINV of a VVVF inverter 2 and the counterelectromotive voltage Vemf of an AC motor 4 is detected by a phase detector 11, and is inputted to a controller 10. The controller 10 which controls the inverter 2, a field power source 6, a main circuit breaker 3 and a switch 9 outputs a field command to raise the field voltage to become equal to the VINV due to the increase of the voltage Vemf so as to stop the AC motor 4, outputs the interruption command of the main circuit and the open command of the switch 9 after the voltage Vemf is raised to the Vemf= VINV, the rising amplitude of the field voltage is determined on the basis of the delta, and the motor then enters the regenerative braking operation by resistor group 8.
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Inventors:
TOYODA MASARU
KAMIYA HIDEO
KAMIYA HIDEO
Application Number:
JP846182A
Publication Date:
July 29, 1983
Filing Date:
January 21, 1982
Export Citation:
Assignee:
MITSUBISHI ELECTRIC CORP
International Classes:
H02P3/22; (IPC1-7): H02P3/22
Attorney, Agent or Firm:
Shinichi Kusano