INVERTER DEVICE

PROBLEM TO BE SOLVED: To provide an inverter device capable of restricting a lowering amount of a carrier frequency to stably control an electric motor when the carrier frequency is lowered by a fact that temperature of switching elements exceeds reference temperature.SOLUTION: A temperature detection circuit 27 detects temperatures of power transistors 23a-23f which are the switching elements. A temperature comparison circuit 28 compares the detected temperature with reference temperatures T1 and T2 (T1>T2). When the detected temperature exceeds the reference temperature T1, a frequency control circuit 29 lowers the carrier frequency for an amount to be calculated according to the detected current of a current detection circuit 25 and the detected temperature of the temperature detection circuit 27. When the temperature of the power transistors 23a-23f becomes lower than the reference temperature T2 thereafter, the frequency control circuit 29 returns the carrier frequency to the carrier frequency of a preset initial value.