Sumitomo Electric Industries, Limited

Toyohashi University of Technology

National University Corporation Toyohashi of Technology

National University Corporation Toyohashi University of Technology

Kyohei Yamada

Hideaki Nakahata

Kenichi Hirotsu

Takashi Ohira

Nobuo Shiga

Daiya Egashira

Satoshi Hatsukawa

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 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.

Growing community of inventors

Toyohashi, Japan

Kyohei Yamada