Power device temperature estimation device for inverter

A power device temperature estimation device that is attached to an inverter and is configured to estimate a temperature of a power device using a temperature of a freewheel diode, the inverter being installed with the power device including a switching element and the freewheel diode connected in anti-parallel with the switching element, the power device temperature estimation device comprising:

• a voltage divider section having a voltage divider circuit that includes a first element and a second element connected in series with each other and is connected in parallel with the freewheel diode;
• a diode voltage detection section that is connected in parallel with the second element to detect a forward voltage of the freewheel diode on the basis of a divided voltage of the second element;
• a diode current detection section that is configured to detect a forward current of the freewheel diode;
• and
• a diode temperature estimation section that has characteristic data on a voltage, a current, and a temperature of the freewheel diode and is configured to estimate the temperature of the freewheel diode on the basis of the detected forward voltage, the detected forward current, and the characteristic data, wherein
• the first element is a diode arranged in forward parallel with the freewheel diode, and the second element is a resistor.