Patent ID: 9203330
Filing Date: 2015-12-01
Classification: F25B,H02P,Y02B

Abstract:
1. A motor control device comprising: an inverter circuit including a plurality of switching elements connected into a three-phase bridge configuration, the switching elements being configured to be on-off controlled according to a predetermined PWM signal pattern so that the inverter circuit converts direct current to three-phase alternating current thereby to drive an electric motor; a current detecting element connected to a direct current side of the inverter circuit to generate a signal corresponding to a current value; a rotor position determination unit configured to determine a rotor position based on phase currents of the motor; a PWM signal generation unit configured to generate a signal pattern of two of three phases so that the pattern follows the rotor position; a current detection unit configured to detect the phase currents based on a signal generated by the current detecting element and the PWM signal pattern, wherein the PWM signal generation unit is configured to increase/decrease a duty in both directions of phase lag side and phase lead side based on any phase of the carrier-wave period regarding a first phase of the three-phase PWM signal pattern; wherein the PWM signal generation unit is configured to increase/decrease a duty in one of the directions of phase lag side and phase lead side based on any phase of the carrier-wave period regarding a second phase of the three-phase PWM signal pattern; and wherein the PWM signal generation unit is configured to increase/decrease a duty in a direction opposite to the direction of the second phase based on any phase of the carrier-wave period regarding a third phase of the three-phase PWM signal pattern, the motor control device further comprising a timing point adjusting unit configured to adjust a detection timing so that the current detection unit detects the current at a fixed timing point with respect to one phase and the current at another fixed timing point with respect to the other phase or so that the current detection unit is capable of detecting the current in a variable timing according to a magnitude of an output voltage supplied to the inverter circuit.