Title:
POWER-SUPPLY FOR INDUCTION WELDING
Document Type and Number:
Japanese Patent JP3052979
Kind Code:
B2
Abstract:
PURPOSE: To obtain a stable and sure control characteristic which corresponds to a change in the circuit constant of a work coil or the like due to a temperature change, a load change or the like by a method wherein, while the driving current of an inverter is being controlled, the carrier frequency of the driving signal of the inverter is changed so as to follow a change in a resonant frequency including the work coil.
CONSTITUTION: The high-frequency output of a full-wave inverter 14 is supplied to a resonant circuit 16 via a transformer 16. The resonant circuit 18 includes a resonant capacitor 21 and a work coil 22, and the work coil 22 guides a high-frequency current to a heater 24 for welding. The current of the resonant circuit 18 is detected by a CT 26, it is input to a microcomputer 30 via a current/voltage conversion circuit 28, and it is fed back to a PLL 32. The output of the PLL 32 is given to one input of an AND gate 40 as an inverter carrier signal, a PWM control signal from the microcomputer 30 is given to the other input of the AND gate 40, and the output of the AND gate 40 is given to an inverter drive circuit 12.
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Inventors:
Hideki Double
Taku Tago
Shigeyoshi Nagamatsu
Kozo Nishikawa
Masayuki Kanda
Taku Tago
Shigeyoshi Nagamatsu
Kozo Nishikawa
Masayuki Kanda
Application Number:
JP7365693A
Publication Date:
June 19, 2000
Filing Date:
March 31, 1993
Export Citation:
Assignee:
Kubota Corporation
International Classes:
B29C65/32; H02M7/48; (IPC1-7): H02M7/48; B29C65/32
Attorney, Agent or Firm:
Yoshito Yamada