Matsushita Electric Industrial Co., Ltd.

Matsushita Refrigeration Company

Yoshiaki Doyama

Masataka Ozeki

Keizo Matsui

Kaneharu Yoshioka

Yoshiteru Ito

Yuji Yoshida

Kanji Kubo

Koji Ebisu

Hideki Nakata

Toru Tazawa

Makoto Yoshida

Mitsuo Ueda

Tomokuni Iijima

Masami Funakura

Kazushige Narazaki

Hideo Matsushiro

Masanori Ogawa

Kanji Haneda

Yukinori Maruyama

Koichi Yamada

Shusaku Watakabe

Izumi Yoshida

Hideo Ogata

A converter circuit has a reactor connectable to an AC power supply. It further has a PWM converter circuit connected to the reactor, the PWM converter circuit including a high speed diode, a rectifier diode and a switching element connected in parallel to the rectifier diode. The converter circuit further has an input current detector for detecting an input current of the PWM converter circuit, a DC voltage level detector for detecting an output voltage of the PWM converter circuit, a voltage polarity detector connected to the AC power supply, and a control device. The control device measures a variation period of the output voltage measured by the voltage level detector to judge a power supply frequency. It then controls the PWM converter circuit based on a power supply frequency judgement result, a detection result from the voltage level detector, an input current detected by the input current detector, and an output voltage detected by the DC voltage detector.

Converter circuit having control means with capability to short-circuit converter output

In a brushless motor driving circuit of the invention, in the starting operation, an applying voltage is low and also the induced voltage is low, so that output values from sample and hold circuits,and,are substantially equal to each other. Thus, an output from a comparing circuit,is substantially equal to an output of a V/f converting circuit,As a result, the starting method which is identical with a conventional method is used. By contrast, when the number of rotation of a brushless motor,is increased, and the induced voltage is started to be observed, the condition is spontaneously shifted to that in which the driving voltage is automatically controlled at each time to an appropriate value for the number of rotation and the load of the motor. Accordingly, the switching operation from the starting control to the normal control is not required.

Brushless motor driving circuit and a method of controlling the brushless motor driving circuit

A motor control apparatus and a motor unit having such a motor control apparatus according to the present invention are constructed to detect a terminal voltage for switching elements of the same phase in a dead time period by a voltage output circuit 10, and to detect the instant when the sign of a phase current changes from the detected terminal voltage by a current sign change detection part 11. Based on the phase of a current sign change timing provided from the current sign change detection part 11 and the phase of a phase applied voltage, the first applied voltage control circuit 14 generates a phase applied voltage command to a switching element modulation circuit 9. Such arrangement makes it possible to provide motor continuous energization or motor energization drive near to 180 degrees at high efficiency, without the provision of any current sensors.

Control apparatus for motor, and motor unit having the control apparatus

A force sensation exhibiting device has a housing which can be grasped by a hand, at least one rotatably or linearly movable motor contained in the housing, an input section where repulsive force information are input, and control circuit for driving and controlling said motor according to the repulsive force information, wherein a force sensation is given to said hand by a drive of the motor.

Force sensation exhibiting device data input device and data input

An inverter control apparatus for controlling a command frequency and a command voltage which are supplied to an inverter which then supplies AC power of a desired frequency, accordingly, to an induction motor. The inverter control apparatus receives a requested rotational speed of the motor and an actual rotational speed of the motor is obtained by detecting a frequency of a fluctuation component of a drive current supplied from the inverter to the induction motor. The difference between the requested rotational speed and the actual rotational speed represents a slip amount, which is added to the requested rotational speed to produce a command frequency. The command voltage is set to a voltage acquired when the monitored drive current is at a minimum value. Thus, the inverter control apparatus is able to maintain power consumption at the lowest possible level in response to changes in the operating environment without requiring a motor constant input or a motor speed detector, while compensating the slip ratio of the induction motor to maintain the motor speed at a target level.

Inverter control apparatus

A data input device includes a housing which can be grasped by a hand. The housing is equipped with a detecting device that detects a displacement or pressure at a portion of the housing on which fingers are placed when the housing is grasped by the hand. The data input device may include plural sensors to detect displacement or pressure at several different finger belly portions of the fingers. Also, plural sensors may be provided for each finger belly portion. The data input device may be used to control the movement of remotely located mechanical fingers or virtual fingers shown on a display.

Force sensation exhibiting device, data input device and data input

A multi-system air conditioner comprises an exterior unit including a compressor and a plurality of interior units, each being installed in a room and including a heat exchanger and an expansion valve therefor. An opening degree of the expansion valve in an interior unit is controlled based on not only the superheat degree of the compressor but also the room temperature difference. Further, the control based on the superheat degree is carried out by means of the fuzzy logical calculation on superheat degree value. A rotational speed of the compressor is controlled based on not only the load capacity of the room but also the room temperature difference. Further, a control based on the fuzzy logical calculation on the pressure value is added. A feed forward control is also added so as to shorten the transient time.

Multi-system air conditioner

A multichamber air conditioner which is provided with a unit for obtaining the characteristics which are approximately conformable to the reverse characteristics of the desired control dynamic characteristics, an integrator, a unit for receiving the detected room temperature as the input of the above described reverse characteristics unit, comparing the output of the above described reverse characteristic unit with the set value, inputting the compared results to the above decided integrator, controlling the opening of the expansion valve by the output of the integrator, outputting the integration gains of the above described integrator in accordance with the open air temperatures, the total sum of the number of driver stands, the performance, and the variation in the compressor suction pressure.

Air conditioner of multichamber type

A reproducing apparatus wherein control of rotation of a rotary head, control of tape transportation and a control of the tracking of the head adjusting actuator are processed in a time-share fashion by a data processing device. The control is carried out by using a timer circuit, which has a period of one or several integer times the period of rotation of the rotary head. Computing processes for the above controls are selectively carried out on a time-shared basis. By using a DC component of the tracking error signal, a track transporting system capable of noiseless playback, and which has a wide range of tracking control.

Video tape reproducing apparatus with a processor that time-shares

Apparatus for reproducing information at variable speeds from a magnetic

A VTR of helical scan type includes a rotary magnetic head fixed on an electro-mechanical converter made of a piezoelectric element and adapted to be displaced along the width of a recording track. In this type of VTR, the rotary head can follow the curving of the recording track, and therefore a superior reproduction output is always produced. Also, a noiseless reproduction image is provided at the time of special reproduction with a tape feed rate different from the recording speed. When the electro-mechanical converter is driven, the average DC component of the drive voltage is desirably reduced to zero to secure a dynamic range effectively. Especially this consideration is necessary to maintain the service life of the piezoelectric element which may make up the electro-mechanical converter. The average DC component of the drive voltage of the electro-mechanical converter is reduced to zero, or specifically, a weighted average of the drive voltage for head scanning is produced, and the drive voltage is appropriately processed during the period when the head is not in contact with the tape.

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Hirakata, Japan

Yoshiaki Doyama