Electric compressor controller

An electric compressor controller includes a compressor (11) that compresses refrigerant of an air conditioning system; a motor (12) that drives the compressor; an inverter (13) that selectively control switching elements (TR1-TR6) based on PWM pulse signals to supply drive power to the motor (12) and heats the refrigerant by heat generated due to switching of the switching elements (TR1-TR6) during a heating operation; temperature detectors (134) each detects junction temperature of each of the switching elements; a drive controller (14,131) that supplies the pulse signals to the inverter (13) to control the inverter; and a slope varying unit (133) that variably controls precipitous degree of rising/falling slope waveforms of the pulse signals based on the junction temperature detected by the temperature detectors. According to the electric compressor controller, efficiency for heating refrigerant is improved, so that its own heating ability is improved.