Abstract: The photoelectric conversion device includes a quantum dot accumulation zone, a base layer having current collecting properties which is disposed on at least one major surface of the quantum dot accumulation zone, and a plurality of columnar carrier collection zones, each extending from the base layer into the quantum dot accumulation zone and having an open end. Each of the carrier collection zones is composed mainly of metal oxide. An open end part has a higher mole ratio of oxygen to metal than a body part other than the open end part.

Abstract: There is provided a quantum dot solar cell having a high optical absorption coefficient. The quantum dot solar cell includes a quantum dot layer 3 including a plurality of quantum dots 1, wherein the quantum dot layer 3 includes a first quantum dot layer 3A having an index ?/x of 5% or more, wherein x is an average particle size, and ? is a standard deviation. The quantum dot layer 3 also includes a second quantum dot layer 3B that is provided on the light entrance surface 3b and/or the light exit surface 3c of the first quantum dot layer 3A and has an average particle size and an index ?/x smaller than those of the first quantum dot layer 3A.

Abstract: A photoelectric converter is disclosed. The photoelectric converter includes a light-absorbing layer. The light-absorbing layer includes a plurality of crystalline grains. The grains contain a Group I-III-VI chalcopyrite compound semiconductor. The light-absorbing layer contains oxygen and an average atomic concentration of oxygen at grain boundaries of the light-absorbing layer is larger than the average atomic concentration of oxygen in the grains of the light-absorbing layer.

Abstract: In a controller, for use in an electric motor, which self-contains a current control system, a conducting portion of a feedback element from a current detector up to a summing point, and a conducting portion of a forward element from the summing point for the current control up to a gate terminal of each of switching devices are mounted in a power module to be hermetically encapsulated without being exposed to the external ambient atmosphere. The distributed processing is executed in the two portions, i.e., a current control loop, and a position control unit, a velocity control unit and an interface processing unit other than the current control loop. Therefore, the current control loop including the current feedback portion is constituted by another sub-microprocessor to be mounted together with the associated devices in a power module which is molded with resin such as epoxy resin.

Abstract: The present invention relates to a control system for a servomechanism device such as robot, and more particularly to a position correcting control system for a servomechanism device which is well suited to perform high-precision positioning or high-perfomance operations on the basis of a sensor feedback control system such as force detection feedback control.

Abstract: A fixed slit plate and a rotary slit plate which is secured to a rotating shaft are provided between two photoconductive elements and a light emitting element, and the two photoconductive elements provide two outputs which have the phase difference .pi. therebetween. These two outputs thus provided are added to extract the dc component, thereafter exerting feedback control over the light emitting element such that this dc component is maintained at a constant level.

Abstract: A system consisting of a motor that drives a load, an analog signal generator that outputs an analog signal which increases as the motor is accelerated, a speed commander that determines a motor speed and commands the motor to operate at the determined speed, and an energizing circuit that receives signal representing difference between the output from the speed commander and the output from the analog signal generator and that energizes the motor so as to operate at the speed in accordance with the signal for the difference is provided with a pulse generator that outputs a pulse corresponding to the current motor speed and with a control circuit that controls the signal for the difference in such way that when the motor is operated at a low speed at which the interval of pulses output from the pulse generator becomes long the signals for the difference issued during a pulse interval sequentially increase.

Abstract: An AC motor such as an induction motor or a synchronous motor is driven by a PWM inverter. Turn-on of the PWM inverter is controlled by PWM pulse signals obtained as a result of comparison between voltage command signals (a modulation signal) and a carrier wave signal. The voltage command signals are obtained as a function of errors between current command signals and detected current signals. Ripples included in the voltage command signals are so suppressed as to be decreased as the rotation speed of the AC motor becomes lower. By so suppressing the ripples, the level of noise generated from the motor can be reduced especially when the motor operates in a low-speed rotation range.

Abstract: A control apparatus for an induction motor wherein an inverter is connected between a power source and the induction motor so as to energize the induction motor through the inverter, characterized in that when an input voltage of the inverter has lowered, a magnetizing current component command is decreased, while a torque current component command is increased.

Abstract: When driving an AC motor with a PWM inverter, the width of a speed command signal is modulated by a carrier to produce width modulated pulses for controlling main switching elements. The width modulated pulses are liable to be attended with impulses which cause magnetic vibrations in the AC motor, resulting in noises. The generation of these impulses can be suppressed by changing the amplification factor of an amplifier for the speed command signal or the amplitude of the carrier on the basis of the rate of change of the speed command signal. Noises which would be attendant on low speed running of the AC motor can be reduced by changing the amplification factor of the amplifier and the amplitude of the carrier on the basis of detected frequency of the speed command signal or revolution of the AC motor during low speed running.

Abstract: Disclosed is a control apparatus for an AC motor which is driven by a power converter constituted by switching elements. A current control circuit turns on/off the switching elements in accordance with a current pattern signal in the form of an AC signal to thereby control the motor current. The current pattern signal is obtained by a current pattern calculating circuit based on a current command signal and a sinusoidal signal which determines the current phase. A current correction signal proportional to the deviation of the motor current from the current command signal is obtained by a current correction control circuit and added to the current command signal to be applied to the current pattern calculating circuit.