Active filter device and electric compressor comprising same

An active filter device comprising:

• a common mode choke coil inserted into a pair of positive-side and negative-side power supply lines;
• a normal mode choke coil connected to the pair of power supply lines or one of the power supply lines;
• a detection unit that detects voltages of the pair of power supply lines;
• an inverting amplifier circuit that inverts and amplifies a common mode voltage detected by the detection unit;
• a Y capacitor connected between an output of the inverting amplifier circuit and the pair of power supply lines;
• a differential amplifier circuit that differentially amplifies a differential mode voltage between the pair of power supply lines, which is detected by the detection unit;
• and
• an X capacitor connected between an output of the differential amplifier circuit and the pair of power supply lines,
• wherein an output voltage of the inverting amplifier circuit is applied to the Y capacitor, and
• an output voltage of the differential amplifier circuit obtained by amplifying the voltage of the positive-side power supply line is applied to the X capacitor connected to the negative-side power supply line, and an output voltage of the differential amplifier circuit obtained by amplifying the voltage of the negative-side power supply line is applied to the X capacitor connected to the positive-side power supply line.