Patent ID: 9580858
Date: 2017-02-28
CPC Classifications: H02M

Claim:
1. A motor control device configured to drive an electric motor via an inverter circuit which is configured to on-off control a plurality of switching elements connected into a three-phase bridge configuration, according to a predetermined PWM signal pattern thereby to convert direct current to three-phase alternating currents, the motor control device comprising: a current sensing element connected to the direct current side of the inverter circuit and configured to generate a signal according to a current value; a PWM signal generation unit configured to determine a rotor position based on phase currents of the motor and to generate three-phase PWM signal patterns so that the patterns follow the rotor position; and a current detection unit configured to detect phase currents of the motor based on the signal generated by the current sensing element and the PWM signal patterns, wherein the PWM signal generation unit is configured to generate the three-phase PWM signals in a manner such that the current detection unit is capable of detecting two-phase currents at two fixed time-points within a carrier period of the PWM signal; wherein regarding a first one of the three-phase PWM signals, a duty thereof is increased/decreased to both phase lag side and phase lead side with reference to any phase in the carrier period; wherein regarding another phase PWM signal, a duty thereof is increased/decreased to both phase lag side and phase lead side with reference to any phase away one half of the carrier period from the reference phase; and wherein regarding the other phase PWM signal, a duty thereof is increased/decreased to either phase lag side or phase lead side with reference to any phase in the carrier period.