INVERTER DEVICE

PROBLEM TO BE SOLVED: To obtain an inverter device which raises voltage tolerance by actively raising the temperature of a switching element, thereby shortening a period before an inverter main circuit can be driven with high voltage.SOLUTION: The inverter device comprises a frequency control circuit 15 which increases carrier frequency of switching elements (power transistors 4a to 4f) by taking advantage of the characteristic of the switching elements that the voltage tolerance increases when their temperature goes high, and a current control directive circuit 17 which increases a reactive current sent to an electric motor 5. When the temperature of the switching elements is lower than a reference temperature T, the frequency control circuit 15 increases the carrier frequency while the current control directive circuit 17 increases the reactive current, causing losses of the switching elements to increase, whereby the temperature of the switching elements is actively raised.