Abstract: An AC motor control device controls an inverter that supplies an alternating current to an AC motor which is a three-phase permanent magnet synchronous motor. The AC motor control device includes: pulse width modulation signal generation means that supplies a pulse width modulation signal to the inverter so that a position detection voltage vector for detection of the position of the rotor of the AC motor is applied to the AC motor; current derivative detection means that detects a current derivative occurring due to application of the position detection voltage vector to the AC motor; rotor position computation means that computes an estimated position of the rotor of the AC motor; rotor position correction means that corrects the estimated position; and drive control means that controls the pulse width modulation signal generation means so as to drive the AC motor.

Abstract: A stepping motor includes a stator, and a rotor disposed in opposed relation to the stator and movable in a predetermined movement direction. The stator has a plurality of main poles, windings for the respective main poles, a plurality of stator teeth disposed on each of the main poles and spaced circumferentially from each other, and stator slots provided between respective adjacent pairs of the stator teeth. The rotor has a plurality of rotor teeth spaced from each other in the movement direction, and rotor slots provided between respective adjacent pairs of the rotor teeth. Slot magnets of hard magnetic inserts each magnetized in a slot depth direction are respectively provided in the stator slots and/or the rotor slots. The slot magnets each have a width that is 60% to 80% of the width of each of the slots as measured in the movement direction.

Abstract: A motor control device is provided, which drives a two-phase synchronous motor. The motor control device includes: control current waveform generating means which generates a control current waveform by superposing a fundamental sinusoidal wave and a reluctance torque correction waveform that suppresses the fluctuation of the reluctance torque of the two-phase synchronous motor; and current control signal generating means which generates a current control signal for supplying a current to the windings of the two-phase synchronous motor according to the control current waveform generated by the control current waveform generating means. The reluctance torque correction waveform may have a waveform profile such that an original waveform having a frequency twice that of the fundamental sinusoidal wave and having a phase matched with that of the fundamental sinusoidal wave is full-wave-rectified to the same sign as or a different sign from that of the fundamental sinusoidal wave.