Temperature inference device and converter system

Abstract

A temperature inference device according to the present invention calculates a junction temperature inference value of a power semiconductor device that is provided in a converter which performs power conversion between AC power of a three-phase AC power source side and DC power of a DC side. The temperature inference device includes an electric current detection unit that detects the value of an electric current flowing through the power semiconductor device; and a junction temperature inference unit that calculates a junction temperature inference value of the power semiconductor device on the basis of the unbalance rate of a three-phase AC power source which is connected to the converter and a provisional junction temperature value which has been calculated on the basis of at least the electric current value detected by the electric current detection unit.

Dependencies are inferred from the claim text.