Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Hitachi Building Systems Engineering and Service Co., Ltd.

Toshiaki Kurosawa

Hiromi Inaba

Takeki Ando

Seiya Shima

Yoshio Sakai

Hiroaki Kuroha

Nobuo Mitsui

Kiyoshi Nakamura

Sadao Hokari

Mutsuhiro Terunuma

Masao Nakazato

Akiteru Ueda

Toshisuke Mine

Hajime Nakashima

Hideaki Takahashi

Korefumi Tashiro

Shigeta Ueda

Yasunori Katayama

Mitsuyuki Hombu

Hisakatsu Kiwaki

Toshimitsu Tobita

Takanobu Hatakeyama

Katsu Komuro

Mitsuyuki Honbu

Seikichi Masuda

Kazuhiko Sasaki

Masahiro Konya

Akihiro Nokita

Takei Ando

Ando Takeki

Hideo Miyao

Katuhito Issiki

An elevator system which is provided with power converters, electric motors supplied with power from the power converters, and a torque distributing section having functions for determining allocation of output power from the power converters on the basis of a required torque, by which an elevator is operated on the basis of functions selected in accordance with the operation mode. The system is able to save power in the elevator operation and also improve control functions and increase system capacity.

Elevator system

In a current source power converting apparatus, in which an AC to DC converter is coupled to a DC to AC inverter through a DC reactor, two energy absorbing devices are coupled to DC terminals of the converter and the inverter, respectively, whereby there is formed a circulation circuit for circulating a current through the two energy absorbing devices and the DC reactor, when a voltage, which is higher than a predetermined value, is induced by an inductance of the DC reactor.

Current source power converting apparatus with overvoltage protection

Control signals for operating power converter switching elements are created using one-chip microcomputers. Pulse patterns required to supply the control signals and their generating timings are previously created and scheduled in pairs. When the times when the control signals are to be supplied to the switching elements have actually come, those control signals are successively output.

Method and apparatus for controlling power converter

A pulse generator (including a microcomputer) for supplying a pulse pattern to semiconductor devices of a power converter (such as an inverter or a converter) using the pulse width control scheme is provided with function of dropping pulses so that the pulse pattern may form a predetermined function provided that the pulse width is shorter than a limit value (Limit). As a result, the input and output waveforms of the power converter can be made sinusoidal and can be released from the constraint of the minimum pulse width of power conversion semiconductor devices.

PWM control for power converter system utilizing pulse dropping at

An elevator control apparatus comprises an inverter device for supplying an induction motor for driving an elevator cage with AC electric power of variable voltage and frequencies and control equipment for controlling the output voltage and frequencies of the inverter device in response to signals produced in floors served by the elevator and in an elevator cage. The inverter device is constructed by a converter unit for converting AC electric power to DC electric power, at the input end of which a capacitor is connected in parallel with an AC electric source, an inverter unit for inverting the DC electric power converted in the converter unit into AC electric power, at the output end of which a capacitor is connected in parallel with an induction motor for driving the elevator cage and a DC reactor connected between the converter unit and the inverter unit. The thus constructed elevator control apparatus does not cause interference in electric appliances such as audio equipment, computer etc. existing within a building in which the elevator is installed.

Apparatus for controlling AC elevators

A dv/dt protection circuit device for an AC-DC converter apparatus including control board switching arrangement having a current cut-off function which conducts an interrupts current from a power source to a load and refluxes the load current while the current is uninterrupted by a full-wave bridge rectifier circuit having a plurality of arms. Each arm of the bridge rectifier circuit connects a reactor for suppressing a rate of change of a power source line voltage of the bridge rectifier circuit at the switching time of the switching arrangement and a condenser is provided for absorbing an overvoltage generated at an inductance on the side of the power source, the condenser being connected on the side of the power source connected to the bridge rectifier circuit.

dv/dt Protection circuit device for an AC-DC converter apparatus

In an elevator wherein an elevator cage is repeatedly run among a plurality of floors by controlling a cage driving motor in accordance with a velocity command; a floor arrival error involved when the elevator cage has arrived at the floor is detected, and the velocity command for the subsequent operation is corrected in accordance with the floor arrival error, thereby to enhance the floor arrival precision.

Elevator control apparatus

An AC-to-DC power conversion by connecting GTO elements to the positive arms of a three-phase full wave bridge circuit and by repeating the mode of supplying power to a load from an AC power supply by controlling the GTO elements, and the mode of making the current flowing to the load flow back at the time of interruption of the power supply mode, when the power supply mode and the flow-back mode are switched over, overvoltage at the time of the switching is suppressed by simultaneously causing the power supply and flow-back currents to flow.

AC-to-DC power converter with improved power factor and overvoltage

An elevator controller which uses an acceleration command signal that has as its initial value a start shock compensation torque which will offset the unbalance torque caused at the time of starting. From the completion of elevator car acceleration to the start of deceleration, the acceleration command is gradually increased or decreased to control the motor so as to provide a smoother motion of the car. After the inception of the car deceleration a velocity command is issued which decreases with the reducing distance between the car and the destination floor.

Controller for elevator

A power converter for power conversion between an a.c. system and a d.c. system includes a full-wave bridge circuit having GTO connected in at least one arm of the full-wave bridge circuit on the positive polarity side. During a conduction-enabled period of GTO which is determined by a firing phase angle, the GTO is so controlled as to perform current chopping operation by a pulse signal of a predetermined pulse width.

Power converter apparatus

A speed control system for an elevator motor, comprising a D. C. motor for driving an elevator, a device which generates a speed command signal for the elevator, a speed dynamo which generates a speed signal corresponding to a speed of the elevator, a speed control device which adjusts an applied voltage to the motor according to the speed deviation between the speed command signal and the speed signal, an emergency stop device which subjects the elevator to braking when the speed deviation has exceeded a predetermined value, and a blind sector device which provides an output when the speed signal has exceeded a predetermined value and which negatively feeds it back to the speed control device.

Speed control system for a motor

A safety apparatus for an elevator system is disclosed in which upon detection an instantaneous power service interruption, an emergency brake is applied to the car and continues to be applied for longer than the time required for the particular car to stop.

Safety apparatus for elevator system

In a speed feedback control system wherein a speed command signal and a speed feedback signal are compared and wherein the deviation between these signals is entered into a speed control unit, the speed signal is differentiated to apply speed damping in order to suppress the oscillations of the control system. In this case, while the speed command and the actual speed make a great difference transiently, the speed command is approximate to the sum between the speed feedback signal and the damping signal even transiently. Therefore, the speed command signal is compared with the sum between the speed feedback signal and the damping signal, and the fault of the speed control system is detected upon the fact that the deviation has exceeded a predetermined value.

Fault detecting system for a control system

A thyristor fault-detecting apparatus comprises a thyristor bridge with A.C. terminals connected to a three-phase A.C. power supply and having six thyristor arms, and an inductive load connected to D.C. terminals of the bridge. Each of the A.C. paths has a saturable reactor with an output winding so set as to be excited by the line current within the range from .pi./3 to 2.pi./3 (rad). Output voltages of the reactors are rectified and added, so that a fault in the thyristor is detected by the disappearance of the added output.

Thyristor fault-detecting apparatus

An over-speed preventing apparatus for the DC motor comprises a DC motor the speed of which is controlled by the adjustment of the armature voltage thereof, controlled-rectifier means for supplying power to the separately excited field winding of the motor, means for generating a predetermined field current command, means for detecting the field current, and a constant current control system for controlling the rectifier means in accordance with the error between the field current command and the detected value of the field current. The apparatus further comprises a unidirectional element connected in parallel to the field winding in the direction in which the field current is made to flow back, current decrease detector means inserted between the rectifier circuit and the parallel circuit including the field winding and the unidirectional element, and protecting means energized by the current decrease detector means.

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Katsuta, Japan

Toshiaki Kurosawa