A power converting apparatus and method includes a converter for converting AC power from a commercial power supply into DC power, a smoothing unit for smoothing the DC power from the converter, an inverter for converting an output of the smoothing unit into another AC power, a control unit for controlling the inverter, and a current detector for detecting an output current of the inverter and providing a detection signal indicative thereof. A cooling device for cooling at least one of the converter or the inverter. The detection signal of the current detector is inputted into the control unit so that the control unit estimates a temperature of the inverter or the converter based on the detection signal and controls a cooling device for cooling based on the estimated temperature.