Solid-State Transformer Circuit Topology for Weight Reduction

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Solution Overview

Problem

Conventional transformers, such as pole transformers and high-frequency transformers, are heavy, difficult to handle, and face challenges with parasitic capacitance, requiring large attachment spaces and magnetic coupling components like coils and iron cores.

Innovation Solution

A solid-state transformer design that eliminates the need for coils and iron cores by using a circuit configuration with front and rear stage circuits featuring capacitors and inductors connected in series or parallel, with switching mechanisms to invert polarity and perform power transmission, allowing for a compact and lightweight transformer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional pole transformer with thick coil and iron core is used, then magnetic coupling and electromagnetic induction are achieved, but the transformer becomes heavy and requires large attachment space

Engineering Contradiction:

Improvemagnetic couplingVSAvoidtransformer weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical magnetic coupling system (iron core and thick coil) with an electronic circuit system comprising switching elements, capacitors, and inductors. This substitution eliminates the need for heavy magnetic components while achieving the same power transformation function through electronic switching and energy storage elements, directly resolving the contradiction between reliability of magnetic coupling and weight of the transformer.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a conventional pole transformer with thick coil and iron core is used, then magnetic coupling and electromagnetic induction are achieved, but the transformer requires large attachment space

Engineering Contradiction:

Improvemagnetic couplingVSAvoidattachment space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Volume of moving object

If a high-frequency transformer is used, then size and weight are reduced, but parasitic capacitance becomes a significant design challenge

Engineering Contradiction:

Improvetransformer sizeVSAvoidparasitic capacitance design

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Weight of moving object

If conventional transformers are replaced with solid-state converter, then size and weight are reduced, but new circuit configuration is required

Engineering Contradiction:

Improvetransformer weightVSAvoidcircuit configuration

Core Design Contradiction:

Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent divides the power conversion function into distinct stages: a front-stage circuit for power factor correction and voltage boosting, and a rear-stage circuit for voltage transformation and power delivery. This segmentation allows each circuit module to be optimized independently, simplifying the overall design and control while achieving the desired size and weight reduction through elimination of magnetic components.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3046243B1Converter or solid state transformer

Publication Date: 2020.09.23 SUMITOMO ELECTRIC INDUSTRIES LTD

Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)

AI summary

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 the front stage circuit and the rear stage circuit 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 one of power transmission from the first port to the second port, and power transmission from the second port to the first port.