Toyohashi University of Technology

Sumitomo Electric Industries, Limited

Denso Corporation

Murata Machinery, Ltd.

National University Corporation Toyohashi of Technology

National University Corporation Toyohashi University of Technology

Takashi Ohira

Nobuo Shiga

Kazuhiro Fujikawa

Kazuyuki Wada

Hideaki Nakahata

Kenichi Hirotsu

Satoshi Hatsukawa

Kyohei Yamada

Naoki Sakai

Daiya Egashira

Tuya Wuren

Kazuya Ishioka

Masayoshi Sugino

Minoru Mizutani

Kazushi Sawada

Satoshi Kitabayashi

Takashi Tsuno

Kazuhiro Ishikawa

Takanari Sasaya

Tetsuo Hirano

Masafumi Hayakawa

Mitsutoshi Nakata

Kotaro Tanimura

Shinji Abe

Motoaki Miyazaki

Takaaki Masaki

Hiroki Kuniyoshi

Makoto Teramoto

In a local cart traveling system, a frame track includes first and second metal rails each with an L-shaped cross section and facing each other. A local cart is within the frame track, and includes a first electricity receiving tire and a second electricity receiving tire to travel on horizontal travel surfaces of the rails. A voltage supplier supplies an AC voltage to the travel surfaces, so that the first metal rail and a first electricity receiving tire define a first capacitor and the second metal rail and the second electricity receiving tire define a second capacitor. The local cart includes a power receiver to receive AC power, and a travel motor that receives power after the AC power is rectified. The frame track includes a connecting plate as an electrical insulator covering portions of the surfaces of vertical walls of the first metal rail and the second metal rail.

Traveling body system

In each E-class inverter, an internal voltage detection circuit detects an internal voltage of a resonant type power supply circuit or a matching circuit and adjusts a phase of a driving signal of a MOSFET based on a detected voltage. It is thus possible to match a phase of a current voltage of a sine waveform of each inverter and combine power highly efficiently. Since power combining is performed highly efficiently without using a variable capacitor and variable inductor, it is possible to suppress upsizing of elements and achieve downsizing of a power amplifier circuit.

Power amplifier circuit including multiple inverters connected in parallel

A wireless power transmission apparatus includes a high-frequency power generator, a power-transmitting electrode, a plurality of power-receiving electrodes, a switchable matching device, a detection circuit and a controller. The high-frequency power generator generates high-frequency power. The power-transmitting electrode is configured to transmit the high-frequency power generated by the high-frequency power generator. Each of the power-receiving electrodes is capable of wirelessly receiving the high-frequency power from the power-transmitting electrode. The matching device is electrically connected with the power-transmitting electrode and includes one or more matching circuits. The detection circuit detects, based on the output of reflected power from the power-transmitting electrode, whether or not the generation of the high-frequency power by the high-frequency power generator and the transmission of the high-frequency power at the power-transmitting electrode match each other. The controller switches the one or more matching circuits of the matching device depending on the detection result of the detection circuit.

Wireless power transmission apparatus, conveyance system employing the apparatus and method of controlling the apparatus

A transformer is provided between a power supply and a load, and includes a front stage circuit and a rear stage circuit each having a function of performing switching so as to alternately invert a polarity of output relative to input. The transformer further includes: a series unit provided in at least one of both circuits and composed of a pair of reactance elements connected in series to each other via a connection point; and a switch device which, with both ends of the series unit serving as a first port, causes a part between one end of the series unit and the connection point, and a part between the other end of the series unit and the connection point, to serve as a second port alternately through switching while inverting a polarity, and executes power transmission from the first port to the second port or vice versa.

Transformer

A high frequency oscillator has a high frequency generation part, an oscillation part, a matching unit, rectification element parts and switch parts. The oscillation part oscillates high frequency power generated by the high frequency generation part. The matching unit is arranged between the high frequency generation part and the oscillation part, and has one or more capacitors and matching circuits having difference characteristics so as to perform matching between the high frequency generation part and the oscillation part. The rectification element parts and the matching circuits are arranged in one-to-one correspondence. The rectification element parts rectify high frequency power supplied from the high frequency generation part to the oscillation part. The switch part is connected to the corresponding rectification element part to switch the corresponding capacitor connected to the corresponding matching circuit through the corresponding rectification element part.

High frequency oscillator and wireless power supply device

A transformer is provided between a power supply, and a load with a resistance value R, and includes a two-terminal pair circuit composed of n-number of reactance elements that are mutually connected, where n is a natural number equal to or greater than 4. With respect to any value of the resistance value R of the load, an input impedance Zof the two-terminal pair circuit has a real number component of k&#xb7;R, where k is a constant, and an imaginary number component of 0. Such a transformer has a small size and a light weight, and does not need a coil, an iron core, and the like as used in a conventional transformer.

A transformer includes a front stage circuit and a rear stage circuit. As a front stage circuit, a switch series unit, which is connected in parallel to a power supply, includes odd-numbered switches and even-numbered switches alternately turned ON. Mutual connection points of the respective switches and points at both ends of the switch series unit are regarded as m nodes in total. Capacitors are provided on at least one of a first electrical path combining odd nodes to lead them to a first output port, and a second electrical path combining even nodes to lead them to a second output port. The capacitors are present so as to correspond to at least (m&#x2212;1) nodes. The rear stage circuit includes an element series unit, which is composed of a pair of semiconductor elements connected in series to each other for conducting operations of mutually opposite polarities, and necessary inductors.

Transformer composed of a front stage circuit and a rear stage circuit

A front stage circuit of a transformer includes a switch series unit, capacitors, and a ground electrical path. The switch series unit, connected in parallel to a power supply, includes odd-numbered/even-numbered switches configured to be alternately turned ON. Assuming that mutual connection points of the switches and points at both ends of the switch series unit are m nodes in total, and one of the points at the both ends is a ground node, the capacitors are provided on at least one of a first electrical path that combines odd nodes and leads them to a first output port, and a second electrical path that combines even nodes and leads them to a second output port, and the capacitors are present to correspond to (m&#x2212;1) nodes excluding the ground node. The ground electrical path connects the ground node directly to the first output port without an interposed capacitor.

Transformer without magnetic coupling, electromagnetic induction or mutual inductance

A transformer of distributed-constant type is provided between an AC power supply with a frequency f and a load with a resistance value R, and includes: a first converter connected to the AC power supply and having a length of &#x3bb;/4; and a second converter provided between an end of the first converter and the load, and having a length of &#x3bb;/4, where a wavelength at the frequency f is &#x3bb;. Such a transformer has a small size and a light weight, and does not need a coil, an iron core, and the like as used in a conventional transformer.

Distributed-constant type transformer for voltage conversion

A power conversion apparatusaccording to an embodiment of the present invention includes a high-voltage side input terminal Tand a low-voltage side input terminal T, first and second output terminals Tand T, a power conversion circuitthat converts direct-current power input between the high-voltage side input terminal Tand the low-voltage side input terminal Tto generate alternating-current power between the first and second output terminals Tand T, and an inverted-voltage generation circuitthat generates an inverted voltage of a common mode voltage generated between the first and second output terminals Tand Tand inputs the inverted voltage to the low-voltage side input terminal T.

Power conversion apparatus with an inverted-voltage generation circuit

A power inverter circuitis a bridge power inverter circuit comprising first and second switching elementssequentially connected in series between input terminals on higher and lower voltage sides and third and fourth switching elementssequentially connected in series between the input terminals on the higher and lower voltage sides and alternately turning on a set of the first and fourth switching elementsand a set of the second and third switching elementsso as to convert a DC power fed between the input terminals on the higher and lower voltage sides into an AC power. One of the sets of the first and third switching elementsand the second and fourth switching elementsis subjected to switching control at a frequency higher than that of the other.

Power inverter circuit having switching elements

Provided is a transistor protection circuit capable of appropriately protecting a transistor even when a switching frequency is high. A transistor protection circuit according to an embodiment of the present invention is a transistor protection circuit for protecting a voltage-driven transistor that is switch-controlled by the application of a high-potential-side voltage or low-potential-side voltage of a power supply to a gate terminal of the transistor by a drive circuit. The transistor protection circuit has a power supply controller that gradually lowers the high-potential-side voltage of the power supply upon receiving a protection command for executing protection of the transistor.

Transistor protection circuit

A switching circuitcomprises a connection circuit cascade-connecting control terminals for controlling switching of n number of transistors M-Mn via n&#x2212;1 number of coils Lrespectively (n is an integer equal to or more than 2; and coils Lrespectively connected between one end of each of the transistors M-Mn and other end of a coil L, one end of the coil Lbeing electrically connected to a DC power source. The transistors M-Mn is sequentially switched with PWM signals inputted to an input terminal of the connection circuit. The switching circuitfurther comprises a transistor Minserted at the one end or the other end of the coil Lin cascade-connection.

Switching circuit and envelope signal amplifier

A switching circuit according to one embodiment has: N switching elements; a connection circuit including N&#x2212;1 first inductance elements that are connected in series; a second inductance element; and N third inductance elements. Control terminals of the N switching elements are connected to ends of the connection circuit and connection contacts, respectively. One end of the second inductance element is connected to a power supply. The N third inductance elements electrically connects one ends of the N switching elements and the other end of the second inductance element with each other, respectively.

A switching circuit according to one embodiment includes first to fourth semiconductor switch elements. A pulse-like signal is applied to each input terminal of the switch elements such that when the first and fourth switch elements are in an ON (OFF) state, the remaining switch elements are in an OFF (ON) state. The switching circuit includes first and second capacitance elements. The first capacitance elements connected between an output terminal of the second semiconductor switch element and the second capacitance elements connected between an input terminal of the second semiconductor switch element and an output terminal of the fourth semiconductor switch element has a capacitance to reduce a parasitic capacitance between the input and output terminals of each of the fourth and second switch elements at a frequency N times (N is an integer of 1 or more) as high as a clock frequency of the pulse-like signal.

Growing community of inventors

Toyohashi, Japan

Takashi Ohira