Kyushu University

Nishimu Electronics Industries Co., Ltd.

Matsushita Electric Works, Ltd.

Nippon Electric Industry Co., Ltd.

Other

Matsushita Electric Industrial Co., Ltd.

Fdk Corporation

University of Tsukuba

Hiroshi Sakamoto

Kosuke Harada

Koosuke Harada

Katsunori Sugimori

Fumiaki Nakao

Hideaki Abe

Mikio Kitaoka

Katsuo Yamada

Toshihiro Torigoe

Tadashi Yamaguchi

Hideki Tamura

Kaoru Furukawa

Shinichi Yamagiwa

Takazi Nakamizo

Satoshi Ohta

Yoshio Matsuo

Masahito Shoyama

Yoshihiro Motomura

Terumichi Nakayama

Keizou Shin

In a data compression method, a data string is compressed in units of symbols, each of the symbols being data having a fixed length. Then, a conversion table in which an entry indicating a correspondence between two or more pre-conversion symbols and one post-conversion symbol is registered is searched, and if it is determined that two or more consecutive symbols in the data string are not registered as two or more pre-conversion symbols, an entry in which the two or more consecutive symbols are registered as two or more pre-conversion symbols is registered in the conversion table, and the two or more consecutive symbols are output without conversion, and if two or more consecutive symbols in the data string are registered as two or more pre-conversion symbols in an entry in the conversion table, the two or more consecutive symbols are converted into one post-conversion symbol, the one post-conversion symbol being in correspondence with the two or more consecutive symbols in the entry.

Data compression/decompression system, data compression method and data decompression method, and data compressor and data decompressor

A noncontact coupler comprising a pair of magnetic coreseach having a U-shaped open magnetic path, a primary coil Land secondary coil Lbeing wound around said coresseparately respectively, said coupler transmitting AC electric power between said primary and secondary coils L, Lby means of an annular closed magnetic path B formed by opposing in proximity both open magnetic face sides of said cores, wherein said primary and secondary magnetic coresare respectively split at least at their sides facing to each other, and a gap forming a spatial magnetic path is interposed between said split pieces. A diameter a of a medium legpositioned inside an annular groovearound in which the coils L, Lare wound (housed) is set almost equal to a width b of the annular groove. These provide effects of lightening a noncontact coupler while securing its performance and improving handleability with enhancing tolerance for positioning of the primary and secondary cores.

Noncontact coupler

A multi-channel output type transformer for outputting uniformly balanced voltage among multiple output channels. The transformer comprising a primary winding and a secondary winding that is wound round a winding shaft portion of a core. The secondary winding of the transformer is a flat cable belt comprising covered conductors corresponding to the number of output channels. The cable belts are arranged in parallel. A plane loop is formed by appropriately folding the flat cable belt, and the plane loop member is arranged to as to substantially orthogonally intersect the winding shaft of the core.

Multi-channel uniform output type transformer

A non-contact electrical power transmission system is capable of providing a large supply current of uniform level at an optimum transmission efficiency. The system includes a power circuit including a power supply of providing a high frequency voltage across a power winding, and a load circuit for energizing a load. The load circuit is composed of a secondary winding, a matching capacitor, a rectifier, and a choke coil. The secondary winding is magnetically coupled to the power winding so as to generate an induced high frequency voltage and to provide a leakage inductance to the load circuit. The matching capacitor is connected across the secondary winding to be cooperative with the leakage inductance and with the secondary winding to form an oscillatory circuit which provides an oscillating voltage across the matching capacitor for generating a supply current being fed through the rectifier and the choke coil to the load. The matching capacitor is selected to have a specific capacitance such that the oscillating voltage reaches its extreme each time the inducted high frequency voltage reverses its polarity. The choke coil is connected in circuit to smoothen the supply current. Thus, the supply current of uniform level can be fed to the load, reducing a possibility of incurring a noise on the supply current, yet minimizing an impedance between the supply circuit and the load circuit for realizing an optimum efficiency of converting the high frequency voltage into the supply current.

Non-contact electrical power transmission system

A power supplying section has a signal transmitting secondary coil which is not inductively coupled to a power transmitting primary coil, and actuates as a feedback coil of a switching element. A load section has a power transmitting secondary coil arranged so as to be confronted with the power transmitting primary coil when the load section is attached to the power supplying section, and also has a signal transmitting primary coil so as to be confronted with the signal transmitting secondary coil when the load section is attached to the power supplying section. When the load section is not attached to the power supplying section, the voltage is not induced in the signal transmitting secondary coil as the feedback coil, and the switching of the switching element is intermittently carried out.

Non-contact power transmitting device having simplified self-oscillation

A magnetic-coupling multivibrator has a rectification circuit including first and second smoothing capacitors connected at a capacitor common junction, the first smoothing capacitor providing a high potential output, the second smoothing capacitor providing a low potential output. A switching series circuit has first and second switching elements connected in series at a common switching junction, the switching series circuit being connected in parallel to the smoothing capacitors. A first saturable transformer has a first saturation coil, a first control coil and a first gate drive coil, and a second saturable transformer has a second saturation coil, a second control coil and a second gate drive coil. A first gate control circuit interfaces the first gate drive coil with the first switching element to effect turn on and off and a second gate control circuit for interfacing the second gate drive coil with the second switching element to effect turn on and off alternately with turn on and turn off of the first switching element to effect continuous oscillation. A current source for driving the first and second control coils to control saturation of the first saturable transformer and the second saturable transformer to effect control of a frequency of the continuous oscillation.

Magnetic-coupling multivibrator

A switching power circuit for battery charger, comprising a single-phase full-wave rectifier circuit formed of diodes, a half bridge circuit formed of first and second switching elements connected in series to each other via a diode; a reactor provided between the single-phase full-wave rectifier circuit and the half bridge circuit of the switching elements and having a secondary coil, a series circuit formed of two diodes connected in parallel across the half bridge circuit, a high-frequency transformer having a primary coil connected between the source terminal of the second switching element in the half bridge circuit and the common junction of the two capacitors in the two-capacitors series circuit a secondary coil at which a high-frequency power is delivered to a load forming a battery charger, and a control circuit consisting of a variable frequency multivibrator to turn on and off the first and second switching elements alternately.

Switching power circuit to supply electric-vehicle battery charger with

The apparatus for non-contacting feeding of a high frequency power according to the present invention comprises a double voltage full-wave rectifier circuit which converts an AC input into a DC output, Royer oscillation circuit consisting of FETs and which receives the DC output from the voltage double full-wave rectifier circuit and provides a high frequency oscillation, the gate windings ofhe FETs being the second winding of a saturable circuit, a starting gate bias stabilization circuit for the Royer oscillation circuit, and a main transformer which delivers a high frequency power produced in the Royer oscillation circuit, through the primary winding of the oscillation-use saturable transformer.

Apparatus for non-contacting feeding of high frequency power

An inverter power supply operating at a high efficiency to provide an AC voltage to a load. The power source includes a DC voltage source and an output transformer with a primary winding, secondary winding, and a feedback winding. An FET is connected in series with the primary winding across the DC voltage source. The primary winding is connected to a capacitor to form a L-C resonant circuit which, in response to the switching of FET, provides across the primary winding an oscillation voltage to be applied through the secondary winding to drive a load, while inducing a feedback voltage across the feedback winding. The oscillation voltage is allowed to go negative at a point between FET and the primary winding. A biasing capacitor is connected to apply an offset voltage which is additive to the feedback voltage so as to give a bias voltage to FET. The power supply is characterized to include a level detector which issues a zero voltage signal when the oscillation voltage is detected to lower to at least zero level, and to include a pulse generator which, in response to the zero voltage signal, produces a pulse of a predetermined pulse-width which overrides the feedback voltage in such a manner as to enable FET to turn on for a ON-period determined by the pulse-width only after the oscillation voltage is lowered to at least zero level, whereby avoiding FET from flowing a current while the oscillation voltage is still positive and therefore reducing a switching loss.

Inverter power supply

The disclosed power source apparatus includes a direct current (DC) source connected to the primary side of a transformer through a main switching element, a shunt circuit connected in parallel to the main switching element the shunt circuit being a serial circuit having an auxiliary switching element and a capacitor, and a control circuit connected to the main switching element so as to operate the main switching element at a duty ratio for generating a pulse-width-modulated output voltage at the secondary-side of the transformer depending on the duty ratio. The control circuit is also connected to the auxiliary switching element so as to turn off the auxiliary switching element when the main switching element is on or 'closed' and to turn on the auxiliary switching element when the main switching element is off or 'open'. The auxiliary switching element and the capacitor in the shunt circuit are such that the shunt circuit has a small impedance at low switching frequencies of the main switching element.

DC-DC converter with surge voltage prevention

A switching power source means comprises a DC voltage source, a first switch element, a low-pass filter connected to the DC voltage source through the first switch element, and a second switch element connected to the input end of the low-pass filter, the switch elements being coupled to the DC voltage source either directly or through a transformer and being operable in such a manner that an output of DC or AC at a desired frequency can be derived across the output end of the low-pass filter. With the invention, a reactor is connected in parallel across the input end of the low-pass filter, to charge and discharge parasitic capacitances of the switch elements, preferably by being provided with a saturable core accompanied by an additional winding supplied with a load current, thus preventing surge currents in the switch elements.

Switching power source means

A switching power source means comprises a DC voltage source, a first switch element, a low-pass filter connectable to the DC voltage source through the first switch element, and a second switch element connected to the input end of the low-pass filter, the switch elements being coupled to the DC voltage source either directly or through a transformer and being operable in such a manner that an output of DC or AC of a desired frequency can be derived across the output end of the low-pass filter. With the invention, a reactor is connected in parallel across the input end of the low-pass filter, which reactor being is adapted to charge and discharge parasitic capacitances of the switch elements, thus preventing surge currents in the switch elements.

A switching power source comprising a pair of output terminals, a first switch element, a reactor and a filter which are connected to each other in series between one of the terminals of an input DC power source and one of the output terminals; a second switch element connected between a connecting node for the reactor and the filter and the other terminal of the input DC power source; and means for causing energy stored in the reactor to be fed back for regeneration to the input DC power source when the switch elements are turned off, wheein the switching power source is characterized by that the first and second switch elements are alternatively actuated for ON-OFF actions at a prescribed time ratio.

Switching power source device having energy recovery

A switching power source device provides a desired AC/DC output by producing a pulse width-modulated waveform through ON-OFF control of a pair or pairs of switching elements connected in series with an input power source, eliminating high-frequency components of the pulse width-modulated waveform with a smoothing choke. The switching power source device is configured so that the input power source will not be short-circuited and consequently suffer a voltage and/or current surge, even when both switching elements in the pair assume the ON status at the same time by dividing the smoothing choke into two portions. The two portions of the smoothing choke are connected in series with the input power source when the switching elements in the pair assume the ON status at the same time.

Switching power source device

A PWM inverter including a saturable core and a main circuit comprising a series circuit of a main winding and a resistor in which switching means applies a DC voltage across the main circuit by time ratio control with the polarity inverted alternately, and the on-off control of the switching means is accomplished by using a saturable transformer with a saturable core.

Growing community of inventors

Kumamoto, Japan

Hiroshi Sakamoto