Abstract: A step-motor-driving device includes (a) a step-motor having driving-windings in plurality of phases, (b) an exciter for supplying power to excite driving-windings, (c) a position detector for detecting a position of a mover of the motor and outputs a position-detecting-signal, and (d) an excitation-timing-controller for receiving a driving-instruction-signal and a position-detecting-signal, and outputs an exciting signal to the exciter responsive to an input of one of the driving-instruction-signal and the position-detecting-signal.

Abstract: A motor control apparatus supplies a current to the motor according to the control either by an average current controller or by an instantaneous current controller. The selection of the controller is done by a switching command signal selector, which selects the average current controller when the position deviation is within a specified range, and selects the instantaneous current controller when the position deviation is outside this specified range.

Abstract: A motor driving power supplying section obtains an output voltage by switching-controlling a predetermined voltage outputted from a main power supply and smoothing a voltage thus switching-controlled. A driving transistor group includes a plurality of driving transistors, for supplying electric power based on the output voltage of the motor driving power supplying section to the motor driving coils of multiple phases. A commutation control section supplies conduction switching signals to the driving transistor group so as to switch successive conduction states of the motor driving coils. An output control section controls the output voltage of the motor driving power supplying section so that a collector-emitter voltage of at least one of the plurality of driving transistors included in the driving transistor group has a predetermined value.

Abstract: A PWM inverter output circuit enabling circuit integration, having a fast response characteristic, and unaffected by dv/dt transients is provided. A predrive circuit 17 drives a power circuit 11 comprising first and second power elements P1 and P2 by controlling the gate and source potential of the power elements P1 and P2 based on a stored control state. The control state is detected from a logic signal output from an input signal processor 13, which converts a command signal instructing turning on and off the power elements P1 and P2 to predetermined logic signals. Operating power is drawn from a main dc power source V1, a control power source V2, and a power supply capacitor C1 that is charged using an output voltage from the control power source V2. The gates and sources of the power elements P1 and P2 are connected together.

Abstract: A protection apparatus used in a brushless motor is arranged by a brushless motor; a commutation signal detecting unit for detecting a position of a movable member of the brushless motor; a speed detecting unit for detecting a rotation speed of the movable member of the brushless motor, involving a rotation direction thereof, in response to the detection signal outputted from the commutation signal detecting unit; and a drive circuit for producing a commutation signal used to drive the movable member of the brushless motor in response to the detection signal outputted from the commutation signal detecting unit and for driving the brushless motor based upon the commutation signal.

Abstract: An output circuit for a PWM inverter is provided which has an N-type first power device and a P-type second power device. Gates of the first and second power devices are connected to each other. Also, emitters of the first and second power devices are connected to each other. An input electrode control circuit controls the voltage applied to the common gates with respect to the common emitters. The voltage may be a positive or negative value, or zero. The input electrode control circuit controls the conduction states of the two power devices based upon the states of input light emitting devices associated with a first and second photocoupler (current generator). When both of the photocouplers are not lit, no current is generated and the conduction states of the power devices are instantaneously interrupted.

Abstract: A driver for an induction motor includes a voltage limiter which limits an upper limit value of an output voltage from an invertor circuit in accordance with an output frequency command, a lowest frequency limiter which limits a lower limit of an output frequency from the invertor circuit, a forward rotation limiter which outputs a first power supply interruption signal when the output frequency from the invertor circuit reaches the upper limit, a reverse rotation limiter which outputs a second power supply interruption signal when a reverse rotational speed of the motor reaches a reverse rotation limit level, and a low-speed overload detector which outputs a third power supply interruption signal when a state in which the second power supply interruption signal is not output continues in a low speed abnormality state.

Abstract: With a view to reduce vibrations generated by a motor and improve resistance to heat, reliability and vibration isolation properties without increasing the cost or the number of manufacturing steps in a rotor for a permanent-magnet motor, a rotor core is formed of an outer peripheral portion by which the permanent magnet is fixed, and a central portion by which a shaft is fixed, a clearance is provided between the outer peripheral portion and the central portion, and the outer peripheral portion is connected to the central portion by means of a plurality of fastening members. Thus, a rotor having excellent vibration isolation properties can be obtained. Since the rotor core is formed of laminated iron plates on which the outer peripheral portion, the central portion and the fastening members are all formed as one piece, resistance to heat, reliability and the vibration isolation properties can be enhanced without increasing the cost or the number of manufacturing steps.

Abstract: A drive apparatus for use in a brushless motor with a rotor and a drive coil assembly. The drive apparatus comprises an energization-state instruction circuit for generating an energization-state instruction signal instructing an energization state of the drive coil assembly on the basis of the position detection signal indicative of a position of the rotor and an energization switching circuit for outputting an energization switching signal to successively switch the energization state of the drive coil assembly in accordance with the energization-state instruction signal and a duty control signal. A power circuit is coupled to a direct-current voltage source and is responsive to the energization switching signal so as to energize the drive coil assembly by means of a direct-current voltage from the direct-current voltage source in accordance with the energization switching signal therefrom.

Abstract: A brushless motor driving device includes a plurality of motor driving coils and a plurality of driving transistors, coupled to the motor driving coils, for periodically supplying an electric power to the motor driving coils. A power supply switching circuit is provided for generating a power supply switching signal for driving the motor driving coils on the basis of a frequency signal corresponding to an oscillation frequency of a voltage controlled oscillator. A phase difference detector is provided for detecting a difference between the power supply switching signal and a counterelectromotive voltage generated in the motor driving coils during a period in which no electric power is supplied to the motor driving coils. The phase difference detected by the phase different detector circuit is used to control the oscillation frequency of the voltage controlled oscillator.

Abstract: In a system for driving a brushless motor having motor drive coils connected to respective drive transistors, voltages induced in the drive coils when the motor is rotating are continuously detected to produce energization switching signals to be applied to the drive transistors, thereby switching over energization of the drive coils, so that the motor can be continuously driven at optimum energization timing regardless of its rotational speed. Further, when a rotational direction command signal is applied to a forward-backward switching circuit to instruct the motor to rotate in the backward rotational direction while the motor is rotating in the forward rotational direction, torque of the opposite direction is produced to change the rotational direction of the motor.

Abstract: The present invention relates to a drive device for a brushless motor utilizing no position detector for detecting the position of a movable element of the motor.The drive device comprises a phase controlled loop for controlling an output of a voltage controlled oscillator (40) by supplying an electric power to motor driving coils (1, 2, 3), detecting the difference in phase between the power supply waveforms thereof and a counterrelectromotive force of the motor driving coils during a power supply interrupting period with the use of a phase difference detector (20) and inputting a detected phase difference signal to the voltage controlled oscillator (40), an oscillation frequency initializing means (70) and a driving transistor interrupting circuit (80).

Abstract: A phase difference between a counter-electromotive voltage induced in a driving coil and a voltage which is applied to the driving coil is detected by comparison of a terminal voltage of the driving coil and a reference voltage. A frequency of a voltage-control oscillator which controls switching of the voltage applied to the driving coil is varied by an output signal made by the comparison, and the phase difference is controlled to be reduced to zero.

Abstract: A speed control apparatus for a motor, wherein the counter-electromotive voltage is detected with great precision even when the counter-electromotive voltage to be caused from the motor driving coils is small or the ambient temperature is changed. The voltages corresponding to the detection voltages are turned into speed signals. The emitter resistance of the driving transistor, which is the cause of the torque reduction, can be removed, and uneven rotation, uneven torque is reduced. The speed control apparatus provides a composite voltage of driving coil voltages that are converted by an inversion amplifier. The voltage corresponding to the composite voltage provides the speed signal. This voltage is transferred to the driving coils and precise speed control is produced without a reduction in the controllable maximum torque or the starting torque.