Patent ID: 7084601

Claim:
A phase current detection apparatus that detects a phase current of a motor based upon a current of a DC link and a vector pattern applied to the motor, the motor being provided in a motor driving apparatus which supplies outputs from a PWM inverter to the motor to drive the motor, comprising: a bypass condenser connected to an input side of the PWM inverter, the bypass condenser being in parallel with a first condenser of the motor driving apparatus, the bypass condenser also being further downstream from a rectifier of the motor driving apparatus relative to the first condenser; a third condenser connected in between the first and bypass condensers and in parallel with both the first and bypass condensers; and a current detector on the DC link of the motor driving apparatus in series between the third condenser and the bypass condenser; and a low-pass filter connected to and parallel with the current detector, wherein a cut-off frequency of the lowpass filter is set to a frequency to substantially suppress a component of a ringing frequency of the motor driving apparatus, wherein the component of the ringing frequency is generated based upon wiring from the bypass condenser to power devices, wiring from the power devices to the motor, and within the motor.