Title:
3-LEVEL POWER CONVERTER
Document Type and Number:
Japanese Patent JP3386308
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To protect capacitors which are provided on the DC sides of a 3-level power converter which outputs 3 levels of voltages to the respective phases from an overvoltage.
SOLUTION: Terminal voltages V3a and V3b of capacitors 3a and 3b by which DC power supplies 5a and 5b are divided into two respectively are detected by a change value detecting means 7 and the extension value ΔT of a short-circuit avoiding period is obtained in accordance with the difference between the respective voltages. For instance, if V3a>V3b, the change value ΔT is outputted to adding means 13b and 13d through a selecting means 9 and, if V3a<V3b, the change value ΔT is outputted to adding means 13a and 13c through the selecting means 9 and the ON-timings of switching devices are delayed to equalize the voltages of the capacitors.
Inventors:
Yasushi Matsumoto
Chiharu Ohsawa
Chiharu Ohsawa
Application Number:
JP3173196A
Publication Date:
March 17, 2003
Filing Date:
February 20, 1996
Export Citation:
Assignee:
Fuji Electric Co., Ltd.
International Classes:
H02M7/537; H02M7/483; H02M7/5387; (IPC1-7): H02M7/537; H02M7/48; H02M7/5387
Domestic Patent References:
| JP795773A | ||||
| JP5316737A | ||||
| JP775345A |
Attorney, Agent or Firm:
Kiyoshi Matsuzaki