| 摘要 |
PROBLEM TO BE SOLVED: To provide a three-level inverter that implements a compact and thin device with long term stability by suppressing a turnoff surge voltage without employing a snubber circuit, and suppressing an operational difference between parallel circuits.SOLUTION: Longitudinally cascaded element packages 11a-12b are arranged so as to be positioned nearer to a centerline CL than diode packages 13a, 13b, so that the first element packages 11a, 11b and the second element packages 12a, 12b have the same arrangement distance from the centerline and thus a minor difference in wiring inductance, and the first and second element packages have a similar condition of occurrence of surge voltage and loss. Negative terminals of first to fourth IGBTs 1a-4b of groups a, b are directly connected together by means of conductors, so that potentials of the negative terminals of the groups a, b of the first to fourth IGBTs are the same to cause a minor fluctuation in a voltage between a control electrode and the negative terminal. |
