Title:
TEMPERATURE RISE DETECTING CIRCUIT FOR INVERTER SWITCHING ELEMENT
Document Type and Number:
Japanese Patent JP3198543
Kind Code:
B2
Abstract:
PURPOSE: To stabilize operation by employing the output from a comparator as a temperature rise detection signal and employing a maximum predicted value of operated temperature as a direct comparison object when an upper limit is set thereby predicting the junction temperature of element accurately.
CONSTITUTION: A VCE loss operating unit 1 receives an average value of inverter output current and operates an average loss against saturated voltage of a switching element (not shown). A switching loss operating unit 2 receives an average value of output current and carrier frequency and operates an average switching loss of element. A temperature difference operating unit 3 divides the sum of both losses by the thermal resistance between the junction cases of the element thus operating the average value of temperature difference between the cases. The operating unit 3 operates a maximum instantaneous value by multiplying the average temperature difference by a predetermined conversion coefficient. A comparator 7 compares the sum of maximum instantaneous temperatures of cooling body, i.e., the junction temperature of the element, with an upper limit thereof and produces a temperature rise detection signal.
Inventors:
Yukio Kato
Application Number:
JP19689991A
Publication Date:
August 13, 2001
Filing Date:
August 07, 1991
Export Citation:
Assignee:
Fuji Electric Co., Ltd.
International Classes:
H02H6/00; H02M1/00; H02M7/48; (IPC1-7): H02M7/48; H02H6/00; H02M1/00
Attorney, Agent or Firm:
Masaharu Shinobe