Patent ID: 9209727
Filing Date: 2015-12-08
Classification: H02M,H02P

Abstract:
1. A motor control device comprising: an inverter circuit including a plurality of switching elements connected into a three-phase bridge configuration, the inverter circuit being configured to convert a direct current into a three-phase alternate current to drive an electric motor; a current detecting element connected to a direct current side of the inverter circuit, thereby generating a signal corresponding to a current value; a PWM signal generating unit which is configured to determine a rotor position based on the phase current of the motor and to generate a three-phase PWM signal pattern so that the signal pattern follows the rotor position; and a current detecting unit which is configured to detect the phase current based on the signal generated by the current detecting element and the PWM signal pattern, wherein the PWM signal generating unit is configured to compare a PWM command voltage and a carrier wave with each other thereby to generate a pulse signal so that a duty is increased or decreased in both directions of phase lag and phase lead with anyone of phases within the carrier period serving as a reference regarding one phase of a three-phase PWM signal; the PWM signal generating unit is configured to generate a pulse signal so that a duty is increased or decreased in one of the directions of phase lag and phase lead with anyone of phases within the carrier period serving as a reference regarding another phase of the three-phase PWM signal; and the PWM signal generating unit is configured to generate a pulse signal so that a duty is increased or decreased in a direction reverse to said one of the directions phase lag and phase lead with anyone of phases within the carrier period serving as a reference regarding the other phase of the three-phase PWM signal, whereby the PWM signal generating unit is configured to generate the three-phase PWM signal pattern so that the current detecting unit is capable of detecting a two-phase current in synchronization with advent of two predetermined time-points within a carrier wave period of the PWM signal with the first to third phases being normally fixed without phase substitution.