Sawafuji Electric Co., Ltd.

Other

Masao Namai

Naoki Akazawa

Hidetake Hayashi

Hitoshi Takimoto

Yuji Nakamura

Toru Yoshioka

In a control system for a motor-generator capable of functioning as a three-phase magnet-type synchronous motor after starting of an engine and functioning as a brushless DC motor before starting of the engine, a rotated-position detecting device is arranged to detect an induced voltage in each of three-phase coils included in the motor-generator and to detect a rotated position of a rotor based on such induced voltage. Thus, the rotated position of the rotor can be detected without use of a sensor, whereby the operation for assembling the motor-generator can be simplified.

Control system for motor-generator

A drive apparatus for a vibrating-type compressor includes a DC power source as well as an inverter including switching elements. The inverter is adapted to convert direct time to alternating current through alternating switching of the switching elements. An inverter control unit is provided for controlling the alternating current supplied from the inverter to the vibrating type compressor. A DC power supply comprises a first power supply including a DC/DC converter. A second power supply is provided including an AC/DC converter. A diode OR circuit is connected to the first and second power supplies. A further circuit is provided which, upon detection of a voltage output from the second power supply, operates to stop the output of the first power supply via a DC/DC converter control unit for controlling the DC/DC converter.

Drive apparatus for vibrating-type compressor

An inverter parallel operation system includes a first inverter adapted to control the output frequency thereof by controlling a control element. The system includes the inverter, and a second inverter and subsequent inverters adapted to control the output frequency thereof by controlling control elements comprising the inverters. Power being fed to a common load after a choke coil provided on the output-side end of a first filter provided on the output side of the first inverter has been connected to a choke coil provided on the output-side end of the second filter on the output side of the second and subsequent inverters. The improvement comprising controlling effective powers output by the first inverter, and the second and subsequent inverters by detecting the effective powers output by both the inverters and controlling any one or both of the output frequencies predetermined in accordance with the effective powers.

Balancing parallel inverter systems

A control circuit for vibrating compressors for converting d-c voltage into a-c voltage to supply a-c voltage to a vibrating compressor (,) comprising a MOS-FET transistor (,) for driving the vibrating compressor (,), a timer IC for generating pulses to switch the MOS-FET transistor (,), a timer forced operation circuit for forcibly reversing the output of the timer IC at a timing at which a counter-electromotive voltage generated by the vibrating compressor (,) during the OFF period of the MOS-FET transistor (,) is restored in the vicinity of 0 volts, a driver for driving the MOS-FET transistor (,) based on the output of the timer IC, and a pulse width changing circuit (,) for detecting an input voltage input into the vibrating compressor (,) and lowering the input voltage to the vibrating compressor (,) by changing the pulse width of output pulses of the timer IC when the input voltage is higher than a predetermined voltage.

Control circuit for vibrating compressors for protecting against excessive voltage and temperature

In a method of driving vibrating compressors having such a construction that a-c voltage is fed to a vibrating compressor by converting d-c voltage into a-c voltage with two MOS-FETs, the two MOS-FETs as switching elements are driven to convert d-c voltage into a-c voltage by changing the ON time of each of the MOS-FETs corresponding to suction and compression strokes in one cycle of the vibrating compressor to improve the operating efficiency of the vibrating compressor. To this end, suction and compression time in one cycle of the vibrating compressor is changed by means of a timer IC.

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Nitta-machi, Japan

Masao Namai