Semiconductor device and power conversion device

A semiconductor device comprising:

• a power semiconductor element;
• a collector substrate electrically connected to the power semiconductor element;
• a collector main terminal electrically connected to the collector substrate;
• an emitter main terminal connected to an emitter electrode surface of the power semiconductor element by a plurality of first bonding wires;
• an emitter reference terminal connected to the emitter electrode surface of the power semiconductor element by a second bonding wire;
• a first voltage measuring circuit to measure a first voltage that is a difference between a potential at the collector main terminal and a potential at the emitter main terminal;
• a second voltage measuring circuit to measure a second voltage that is a difference between a potential at the emitter reference terminal and a potential at the emitter main terminal;
• and
• a deteriorated section identifier to refer to correspondence information that defines a deteriorated section of a plurality of bonding sections to the emitter electrode surface to which the first bonding wires are connected, for a combination of temporal change of the first voltage and temporal change of the second voltage, and to identify the deteriorated section corresponding to a combination of temporal change of the first voltage measured by the first voltage measuring circuit and temporal change of the second voltage measured by the second voltage measuring circuit.