Patent ID: 9059657
Filing Date: 2015-06-16
Classification: H02P

Abstract:
1. A motor control device comprising: a current detecting element connected to a direct current side of an inverter circuit driving an electric motor and configured to generate a signal corresponding to a current value; a PWM signal generation unit which is configured to determine a rotor position based on phase currents of the motor and to generate a three-phase PWM signal pattern so that the pattern follows the rotor position; a current detection unit which is configured to detect the phase currents based on a signal generated by the current detecting element and the PWM signal pattern; and a duty compensation unit which is configured to compensate for a duty of the PWM signal pattern, wherein: the PWM signal generation unit is configured to increase/decrease the duty in both leading and lagging directions based on any phase of a carrier period regarding a phase in which duty becomes maximum among three-phase PWM signals; the PWM signal generation unit is configured to increase/decrease the duty in one of the leading and lagging directions based on any phase of the carrier period regarding a phase in which duty becomes minimum among three-phase PWM signals; regarding a phase in which duty is intermediate between said two phases, the PWM signal generation unit is configured to increase/decrease duty in the other of the leading and lagging directions based on said any phase, thereby generating a three-phase PWM signal pattern so that the current detection unit is capable of detecting two-phase currents at two time-points fixed within the carrier period of the PWM signal; and the duty compensation unit is configured to increase/decrease, before and after changing an increasing/decreasing direction of three-phase duties, the duties thereby to compensate for the duties.