A novel motor controller controls a stepping motor and includes a command value calculator to calculate and output a speed command value and an angle command value based on a reference clock. A control method selector is included to select one of the open-loop control and the closed-loop control in accordance with the speed command value. A command value output unit is included to output a first target value as the first current command value when the open-loop control is selected and outputs a second target value as the second current command value when the closed-loop control is selected. The motor controller controls the stepping motor based on the first target value when the open-loop control is selected and the second target value when the closed-loop control is selected.

AC motor rotates independent from power frequency gives advantages in size and controllability. Oscillating and rotating magnetic field is created across airgap by using Amplitude Modulated input. Higher frequency (Carrier) is the power input and the lower frequency (Signal) determines speed of the motor. Stator and Rotor work as primary and secondary of transformer, rotor windings are arranged to keep resultant EMF generated within the winding as zero when rotor aligned with stator magnetic field and increase when deviates. The current generated on deviated rotor winding creates a push back torque keeping the rotor aligned with magnetic field. This interlocks magnetic field and the rotor. Two different frequencies are applied at either end of the stator windings so that the current flow through each winding become amplitude modulated, average of the two frequencies become carrier frequency and control frequency is half of the difference between two frequencies.

AC motor rotates independent from power frequency gives advantages in size and controllability. Oscillating and rotating magnetic field is created across airgap by using Amplitude Modulated input. Higher frequency (Carrier) is the power input and the lower frequency (Signal) determines speed of the motor. Stator and Rotor work as primary and secondary of transformer, rotor windings are arranged to keep resultant EMF generated within the winding as zero when rotor aligned with stator magnetic field and increase when deviates. The current generated on deviated rotor winding creates a push back torque keeping the rotor aligned with magnetic field. This interlocks magnetic field and the rotor. Two different frequencies are applied at either end of the stator windings so that the current flow through each winding become amplitude modulated, average of the two frequencies become carrier frequency and control frequency is half of the difference between two frequencies.

A motor drive control device includes a control unit generating a control signal Sd such that one-phase excitation of exciting, of coils and of two phases of a two-phase stepping motor, a coil for one phase and two-phase excitation of exciting the coils for two phases are alternately repeated, and a drive unit driving the coils of two phases based on the control signal Sd. An energization angle θ representing a magnitude of an electric angle for continuously energizing the coil of one phase in one direction is capable of being set in the control unit. Specifically, the control unit determines a period T1n for performing the one-phase excitation based on a back electromotive voltage generated in the coil non-excited in the one-phase excitation, and determines a period T2n for performing the two-phase excitation based on an elapsed time per unit angle while the two-phase stepping motor is being excited and the energization angle θ.

A motor drive control device includes a control unit monitoring a rotational state of a rotor of a two-phase stepping motor, setting an energization angle θ representing a magnitude of an electric angle for continuously energizing, of coils of two phases of the two-phase stepping motor, a coil of one phase in one direction based on the rotational state of the rotor, and generating a control signal Sd for controlling driving of the two-phase stepping motor based on the set energization angle θ, and a drive unit driving the coils of two phases based on the control signal Sd.

This motor control device has an inexpensive configuration and enhances motor current target value tracking. This motor control device has an H bridge circuit that has a switching element and is connected to a motor coil provided in a motor, and a control means that drives the switching element at each prescribed PWM period and specifies an operation mode for the H bridge circuit from among a charge mode for increasing the motor current (Icoil) flowing through the motor coil, a fast decay mode for decreasing the motor current, and a slow decay mode. In each PWM period, the control means selects one of the operation modes on the basis of the result of comparing the motor current and a current reference value (Iref) before the time that has passed from the start of the PWM period reaches a prescribed current control re-execution time (Tr) and selects one of the operation modes on the basis of the result of comparing the motor current and the current reference value after the time that has passed reaches the current control re-execution time.

This motor control device has an inexpensive configuration and enhances motor current target value tracking. This motor control device has an H bridge circuit that has a switching element and is connected to a motor coil provided in a motor, and a control means that drives the switching element at each prescribed PWM period and specifies an operation mode for the H bridge circuit from among a charge mode for increasing the motor current (Icoil) flowing through the motor coil, a fast decay mode for decreasing the motor current, and a slow decay mode. In each PWM period, the control means selects one of the operation modes on the basis of the result of comparing the motor current and a current reference value (Iref) before the time that has passed from the start of the PWM period reaches a prescribed current control re-execution time (Tr) and selects one of the operation modes on the basis of the result of comparing the motor current and the current reference value after the time that has passed reaches the current control re-execution time.

A stepping motor drive device which drives a stepping motor comprises a generation module configured to generate a current value waveform for rotating the stepping motor at a unit of a predetermined step angle; a drive module configured to excite the stepping motor using the current value waveform to rotate the stepping motor; and a control module configured to decrease a current value at a balance angle at which the stepping motor is stabilized at the time of non-excitation in the current value waveform of one rotation generated by the generation module.

A stepping motor drive device which drives a stepping motor comprises a generation module configured to generate a current value waveform for rotating the stepping motor at a unit of a predetermined step angle; a drive module configured to excite the stepping motor using the current value waveform to rotate the stepping motor; and a control module configured to decrease a current value at a balance angle at which the stepping motor is stabilized at the time of non-excitation in the current value waveform of one rotation generated by the generation module.

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.