Hitachi, Ltd.

Kyozo Tachibana

Takashi Tsuboi

Genichi Matsumoto

Shozuchi Miura

Yoshio Nozaki

Yoshio Okumura

Hiroshi Sato

Koichi Sugimoto

Mitsugu Matsutake

Yoshio Tsutsui

Hisakatsu Kiwaki

Toshihiko Sakai

Hiroshi Sugai

Hiroaki Ishikawa

Hisaaki Hirabayashi

Hisakazu Ninomiya

Tatsuo Horie

Yoshimitsu Onoda

Katsuaki Suzuki

Kaoru Tamura

Fujimaro Imaizumi

Takao Goto

Shigeru Hatano

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. It is characterized in that a plurality of algorithms for correcting a position target value on the basis of a sensor signal are prepared and are switchedly used so as to readily switch functions, depending upon whether the purpose of a sensor control is a high-precision control or any other high-performance control, that the position target value is corrected through a threshold characteristic element or a dead band element so as to make effective the correction of the position target value based on the sensor signal, and that a correcting signal is applied through a response lag element so as to attain stabilization owing to a viscous effect bestowed on the position correcting operation based on the sensor signal.

Position correcting control system for servomechanism device

The two secondary windings of a transformer the primary winding of which is connected to an AC power supply are each provided with a controlled rectifying circuit. The DC sides of the rectifying circuits are connected in series to supply power to DC motors. One of the secondary windings is detachably connected with a capacitor bank. The capacity of the capacitor bank is selected so that the power factor of the converter can be improved to a satisfactory value when the two rectifying circuits are both controlled to produce output voltages. The capacitor bank becomes connected in response to the fact that the current in the primary winding of a transformer has arrived at a predetermined value.

Power factor improving apparatus for power converter

A power converter apparatus for an a.c. electric rolling stock comprising two transformers, each including a primary winding and a plurality of secondary windings generating the same output voltages but having different internal reactances; a pair of phase-controlled bridge rectifier circuits, each being connected to one secondary winding of each transformer; and diode bridge rectifier circuits connected to the other secondary windings, wherein the windings connected to the pair of phase-controlled bridge rectifier circuits have different internal reactances, and the phase-controlled bridge rectifier circuits are simultaneously controlled, and when the maximum output voltages from the phase-controlled bridge rectifier circuits are reached, the output voltages from the diode bridge rectifier circuits (non-phase-controlled) are increased to their maximum values, then the output voltages from the phase-controlled bridge rectifier circuits are decreased to their minimum values.

Electric power converter apparatus for an a.c. electric rolling stock

A power converter control system for use with a power converter of the type which comprises a plurality of cascade-connected converter units of which at least one converter unit is subjected to continuous control of its conduction phase angle and the remaining converter units are subjected to on-off control of their conductivity is arranged to include a master controller for instructing the number of the converter units to be rendered operative, a reversible counter operative to change its content in response to a phase controlling command applied to the continuously controlled converter unit indicating a maximum or minimum conduction phase angle or delayed phase angle in conduction, a unit change control unit for producing unit changing operation signals to be applied to the respective converter units for controlling the operation of the same, by using one of the binary bits derived from the counter without modification and decoding the remaining bits, and a comparing and identifying circuit which compares the content of the reversible counter with the output of the master controller and causing the reversible counter to operate in response to the aforementioned phase control command until the content of the same becomes identical to the output of the master controller.

Power converter control system

A power converter control apparatus comprising continuously controlled converter units and on-off controlled converter units for effecting powering control and regenerative braking control of a DC motor, which is arranged to include a unit change circuit for generating unit changing operation signals in response to a command for instructing the number of the converter units to be rendered operative from a master controllerand conduction phase signals from a phase shifter. In accordance with the unit changing operation signals, the conduction phase signals from the phase shifter are applied as a gate signal to the continuously controlled converter units in response to a powering control or a regenerative braking command, while a minimum conduction phase signal is applied as a gate signal to the on-off controlled converter units in response to a powering control command signal and a maximum conduction phase signal including a commutation marginal angle in response to a regenerative braking command signal. On the other hand, the gate signals supplied to the continuously controlled converter units may be temporarily cut off by a gate cut-off circuit and at the same time the conduction phase in the output of the phase shifter may be restored.

Power converter control apparatus

This invention is applied to a power converter with a converting apparatus comprising one or more units including only controlled rectifiers or combination of controlled rectifiers and non-controlled rectifiers, said converting apparatus being connected with an AC power source, whereby high harmonic currents generated in the AC circuit during commutating periods are reduced. In the present invention, at the commutating period of the converting apparatus, the reactance in the AC circuit of the converter is changed to increase in accordance with change of the AC current of the converting apparatus, so that the change of the AC current during the commutating period is made more slowly thereby reducing high harmonic currents.

High harmonic current reducing apparatus in power converter

A power converter system comprises a connection of a plurality of controlled rectifiers and a plurality of uncontrolled rectifiers, or a connection of only a plurality of controlled rectifiers. With an AC power supply as an input, the firing phase of the controlled rectifiers is controlled for conversion into a desired power. The commutating operation of the rectifiers is performed by utilizing the AC power supply. A retardation coil is connected to each of the rectifiers connected in series in the same polarity and making up an arm of the connection. The thus connected retardation coils are magnetically coupled with each other. The inductance of the commutating circuit is smaller when the output of the power converter is substantially maximum or minimum than the inductance when the output of the system is not maximum or minimum, thereby effectively reducing the higher harmonics components of the AC input current of the system at the time of commutating operation of the rectifiers without reduction of the utility of the converter.

Power converter system

A controlled AC-to-DC converter comprising a transformer having at least three taps including a center tap and first and second taps, a first thyristor whose cathode is connected to said first tap of said transformer, a second thyristor whose cathode is connected to said second tap of said transformer, a diode whose cathode is connected to said center tap of said transformer, a first output terminal connected to said cathode of said diode, a second output terminal connected to anodes of said first thyristor, said second thyristor and said diode, a D.C. output being produced across said first and second output terminals, and a retardation coil incorporated between said center tap and an electrical juncture between said cathode of said diode and said first output. In such converter, high harmonic frequency components generated in the A.C. current on the power source side are reduced without the disadvantage of the lowering of the efficiency.

AC-to-DC converter

A static power converter includes a plurality of thyristor bridges. The level of the control voltage is measured and a signal representative of the measured level is generated which causes one thyristor bridge to maintain a substantially zero output D.C. voltage, while another thyristor bridge operates with phase shift control.

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Ibaraki, Japan

Kyozo Tachibana