Patent ID: 9431935
Filing Date: 2016-08-30
CPC Classification: H02P

Claim Text:
1. A control device of a three-phase AC motor comprising: an inverter that drives the AC motor; a current sensor that senses a current flowing in a sensor phase among three phases of the AC motor as a sensor phase current; and a controller that switches on and off a switching element of the inverter to control a current flowing through the AC motor, wherein the controller includes: a current estimation device that estimates a d-axis current estimated value and a q-axis current estimated value based on the sensor phase current and an electric angle of the AC motor; and a zero-crossing interpolation device that interpolates a command value relating to a voltage of the AC motor when the sensor phase current is in a predetermined zero cross range, which includes a zero point, and wherein, when the sensor phase current is in the zero cross range, the zero-crossing interpolation device interpolates the command value with a continuous variable value.