Patent ID: 8308442

Claim:
An integrated electric compressor comprising: a compressor constituting an on-vehicle air conditioner; a motor for driving the compressor; a control board for controlling the operation of the motor; and a housing for accommodating the compressor, the motor, and the control board, characterized in that the integrated electric compressor is mounted on a vehicle, the integrated electric compressor further comprises a ripple reducing circuit which is provided between a battery which is a DC power source for applying a voltage to the motor and the control board to reduce ripples of a DC voltage supplied from the battery, wherein the ripple reducing circuit comprises a capacitor and a reactor, wherein capacities of the capacitor and the reactor of the ripple reducing circuit are set so as to avoid resonance with a rotation period of the motor and resonance with a switching frequency of an inverter for driving the motor, wherein taking an inductance of the reactor as L, and a capacitance of the capacitor as C, a resonance point Flc determined by the reactor and the capacitor is expressed by the following equation (1), F 1 c= 1/(2*π*( L*C ) 1/2 ) (1) and as to the resonance point F 1 c, the inductance L and the capacitance C are selected so that the following relationship (3) holds direct current fluctuation frequency Fm (maximum value)<F 1 c<carrier frequency Fpwm . . . (3).