Abstract: A thin spindle motor having a stator core with sufficient swaging strength even using thin magnetic steel sheets is provided, whereby the magnetic loss and the power consumption of the spindle motor are reduced. The stator core is formed by laminating plural stator laminations with a thickness of 0.1 to 0.2 mm and joined by a swaging portion. The swaging portion has an approximately rectangular shape having long sides extending along a radial direction when viewed from an axial direction. The swaging portion has a cross section with a middle portion parallel to the radial direction and a slope portion at the both sides when viewed from a circumferential direction, thereby forming a recess. The recess has a depth that is less than the thickness of the stator lamination whereby the swaging portion does not cut the stator lamination.

Abstract: A thin spindle motor having a stator core with sufficient swaging strength even using thin magnetic steel sheets is provided, whereby the magnetic loss and the power consumption of the spindle motor are reduced. The stator core is formed by laminating plural stator laminations with a thickness of 0.1 to 0.2 mm and joined by a swaging portion. The swaging portion has an approximately rectangular shape having long sides extending along a radial direction when viewed from an axial direction. The swaging portion has a cross section with a middle portion parallel to the radial direction and a slope portion at the both sides when viewed from a circumferential direction, thereby forming a recess. The recess has a depth that is less than the thickness of the stator lamination whereby the swaging portion does not cut the stator lamination.

Abstract: A power conversion apparatus is formed by connecting unit communication-assisting means in series between an alternating-current terminal incorporated in a conventional current-type power conversion apparatus, and an alternating-current load. The communication-assisting means includes reverse-blocking-type self-commutated devices and a capacitor. By controlling the switching of the reverse-blocking-type self-commutated devices, a voltage is generated at the capacitor and additionally used for a power supply commutation operation or load commutation operation. By virtue of this structure, the power conversion apparatus can easily provide a large capacity (high voltage, large current), and can be improved in power factor. Further, the structure enables the number of required fundamental elements to be reduced, and hence enables the power conversion apparatus to be produced easily at low cost.

Abstract: A power conversion apparatus is formed by connecting unit communication-assisting means in series between an alternating-current terminal incorporated in a conventional current-type power conversion apparatus, and an alternating-current load. The communication-assisting means includes reverse-blocking-type self-commutated devices and a capacitor. By controlling the switching of the reverse-blocking-type self-commutated devices, a voltage is generated at the capacitor and additionally used for a power supply commutation operation or load commutation operation. By virtue of this structure, the power conversion apparatus can easily provide a large capacity (high voltage, large current), and can be improved in power factor. Further, the structure enables the number of required fundamental elements to be reduced, and hence enables the power conversion apparatus to be produced easily at low cost.

Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3. Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.

Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3. Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.

Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3 Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.

Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3. Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.

Abstract: An inverter control apparatus comprises a controller, a mode decision circuit and a voltage reference conversion circuit. The mode decision circuit determines one of three kinds of modes which may be used to control the inverter, namely, a normal mode, a rectangle mode and zero correction mode selected according to values and polarities of multi-phase voltage reference signals. The voltage reference conversion circuit corrects the voltage reference signals according to the determined mode in the mode decision circuit. In the case of the normal mode, the mode decision circuit outputs the previous voltage reference signal V* without change as the new or corrected voltage reference signals. In the case of the rectangle mode, the circuit fixes the voltage reference signal V* having the greatest value of the three phase (U-phase, V-phase and W-phase) to a minimum voltage reference V.sub.min which is of opposite polarity to the selected greatest value signal, or, in another embodiment, to a zero value.

Abstract: There is disclosed a method of controlling an induction motor, which controls a primary current of the induction motor on the basis of a magnetic flux component current command i.sub.1d *, a torque component current command i.sub.1q *, and a slip frequency command .omega..sub.s which are orthogonal component command values of the primary current of the induction motor, wherein control parameters R.sub.2 *, l.sub.2 * and M* set in accordance with a secondary resistance R.sub.2, a secondary leakage inductance l.sub.2 and a mutual inductance M of the induction motor are used to calculate the magnetic flux component current command i.sub.1d *, the torque component current command i.sub.1q * and the slip frequency command .omega..sub.s. Even in the case where the mutual inductance M of the induction motor varies, if the coefficient 1/M* is assumed as a magnetic saturation function given by a gap magnetic flux, the influence of the magnetic saturation can be canceled.

Abstract: An inverter control apparatus comprises a controller, a mode decision circuit and a voltage reference conversion circuit. The mode decision circuit determines one of three kinds of modes which may be used to control the inverter, namely, a normal mode, a rectangle mode and zero correction mode selected according to values and polarities of multi-phase voltage reference signals. The voltage reference conversion circuit corrects the voltage reference signals according to the determined mode in the mode decision circuit. In the case of the normal mode, the mode decision circuit outputs the previous voltage reference signal V* without change as the new or corrected voltage reference signals. In the case of the rectangle mode, the circuit fixes the voltage reference signal V* having the greatest value of the three phase (U-phase, V-phase and W-phase) to a minimum voltage reference V.sub.min which is of opposite polarity to the selected greatest value signal, or, in another embodiment, to a zero value.

Abstract: A self running type elevator system using linear motors in which a control of power supply to a plurality of elevator cars can be achieved without increasing the size of the system enormously. The system includes at least one travelling corridors, each of which is equipped with a primary coil of a linear motor; a plurality of elevator cars placed inside the travelling corridors, each of which is equipped with a secondary conductor of the linear motor; and a plurality of control device means, provided in correspondence to the elevator cars, for controlling a supply of a driving power to the primary coil at a position of the elevator car such that the elevator car is driven by a driving force produced between the primary coil and the secondary conductor of the linear motor by the driving power.

Abstract: A feedback controller inputs a reference signal instructing a controlled variable output from an object operated in accordance with a control signal and a feedback signal, to calculate the control signal such that the feedback signal is equal to the reference signal, and to supply the calculated control signal to the object. The controller has a transfer function Gf, and functions to generate the following response waveform f (t) due to a disturbance. That is, a response waveform of the controlled variable at the time when the disturbance is added to the controlled object is set to f (t), a response waveform of the feedback signal in an opened loop state, such that feedback of said controlled variable is turned off, is set to p (t), a relative degree of the disturbance is set to "d", and a relative degree of the controlled object is set to "g".

Abstract: A control computation unit includes a delay element in addition to an integrating element and a proportional element. The delay time of this delay element is selected, following the time necessary for due settling (namely, the time required for rendering a controlled variable to follow changes in a control variable command), or the time necessary to restore the controlled variable to the control variable command when a controlled object involved has incurred a certain external disturbance. In case there exist a computation delay time, a dead time, and/or a detection delay time, respectively in the control computation unit, controlled system, and/or a control variable detector, then the delay time is selected equal to one of the computation delay time, dead time, and the detection delay time, or the sum of these times.

Abstract: A rotation detector includes a rotary disk in which slits are recorded, and a photodetector for reading the slits with a laser beam. The slits is constituted by concave and convex parts having different widths radially formed on one surface of the rotary disk at different intervals. The width of one of the concave and convex parts constituting the slits which has a smaller width or slit interval is set to be smaller than the spot size of the laser beam.

Abstract: A control device for a servo motor comprises feedforward means for correcting a speed reference obtained by a position control device by a correction amount obtained on the basis of an objective position or an objective speed of the servo motor so that a response delay of the position control device for obtaining a reference speed necessary to control the rotation angle position of the servo motor to an objective rotation angle position is compensated for while restricting vibration.

Abstract: To the primary winding of a synchronous electric machine, a polyphase a.c. excitation signal from an excitation circuit is applied. Thus, an induced voltage signal, the phase of which varies by an angle proportional to a rotational position of a rotary body, is produced on the secondary winding of the synchro. A phase difference produced between the a.c. excitation signal and the induced voltage signal is detected by a phase difference detecting circuit. This phase difference detecting circuit detects not only a phase difference itself, but also detects the time at which the phase difference has been detected. On the basis of the phase difference and the time thus detected, a predictive computation circuit predicts a rotational position of the rotary body at an arbitrary time.

Abstract: A reactive power compensation apparatus for compensating for voltage fluctuation of an AC power supply system includes a first arithmetic circuit for synthesizing a positive-phase fundamental wave voltage signal from voltages of the AC power supply system, a second arithmetic circuit for synthesizing negative-phase voltage signals from the voltages of the AC power supply system, a third arithmetic circuit, coupled to the first and second arithmetic circuits, for synthesizing current instructions from the positive-phase fundamental wave voltage and the negative-phase voltage signals, and a circuit, coupled to the third arithmetic circuit, for generating a reactive power corresponding to the current instructions.

Abstract: In a reactive power compensation apparatus for compensating reactive power generated by a load connected to an AC power supply system, dual phase current signals obtained by dual phase-converting the load currents and unit dual phase voltage signals synchronized with voltages of an AC main line connected to the load are used, and arithmetic operations thereof are performed to separately detect an in-phase reactive component signal and opposite phase component signals of the load currents. Current commands are generated on the basis of the separately detected signals, thereby controlling the reactive power compensation apparatus on the basis of the current commands.

Abstract: A control system capable of improving a disturbance response characteristic, includes a control processing unit and a power converter. The control processing unit includes apparatus for (a) providing a signal A equal to a predetermined transfer function G.sub.X (s) of a detected value of a controlled variable n, (b) providing a signal B equal to a transfer function [1+G.sub.X (s).multidot.G.sub.LH (s)] of a first command value, and (c) providing, as a second command value, a difference T* between said A and B signals, where G.sub.LH (s) is a simulated transfer function which is from T* to n. The power converter controls the controlled variable according to the second command value.