Abstract: A motor control device includes a driving control part and an upper limit value setting part. The driving control part controls motor driving by switching between a first driving mode and a second driving mode, and controls an output duty ratio so as not to exceed a duty ratio upper limit value. The upper limit value setting part sets, as the duty ratio upper limit value, a low rotation duty ratio upper limit value, a maximum duty ratio upper limit value corresponding to a maximum output value, and an upper limit value of a transition period from the low rotation duty ratio upper limit value to the maximum duty ratio upper limit value, and changes slope information indicating a change amount in the upper limit value of the transition period according to the driving mode when switching between the first driving mode and the second driving mode.

Abstract: A motor control device which controls a motor having an output shaft includes a vehicle speed detection part and a driving control part. The vehicle speed detection part detects a vehicle speed, which is a traveling speed of a vehicle mounted with the motor. Based on the vehicle speed detected by the vehicle speed detection part, the driving control part performs control of switching between a first driving mode which drives the motor, and a second driving mode in which a number of revolutions of the output shaft and an output of the motor are higher than in the first driving mode.

Abstract: The invention reduces the stoppage of operation due to a sudden decrease in rotation speed. A motor device includes a motor that is rotationally driven; a drive signal generator that controls a duty ratio indicating a drive output of the motor so as not to exceed a duty ratio upper limit value, and generates a drive signal corresponding to the duty ratio; an inverter that outputs an output signal for rotationally driving the motor based on the drive signal; a rotation speed detector that detects a rotation speed of the motor; an acceleration detector that detects whether the motor is accelerating; and an upper limit value setting part that changes the duty ratio upper limit value to a second upper limit value higher than a preset first upper limit value in response to rotation of the motor being accelerating.