Series Voltage Regulator with Magnetic Decoupling for Short-Circuit Protection

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Solution Overview

Problem

Existing voltage regulators in electrical networks are inadequate in protecting against high-amplitude short-circuit currents, which can damage the converter and are expensive due to the need for high-performance switches to handle fault currents.

Innovation Solution

A voltage regulator with a magnetic circuit featuring a third decoupling core and a virtual air gap, allowing for magnetic saturation and decoupling during faults, enabling efficient voltage regulation and protection without the need for superconducting materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a known transformer is used for voltage conversion, then voltage regulation can be achieved, but the converter is vulnerable to damage from high-amplitude short-circuit currents

Engineering Contradiction:
Improveconverter protectionVSAvoidshort-circuit current damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The magnetic circuit is segmented into three separate cores (first core, second core, third core) that are magnetically coupled but structurally independent. This segmentation allows the third core to be specifically designed for fault current management while the first and second cores handle normal voltage regulation, isolating the converter from direct exposure to short-circuit currents.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third core acts as an intermediary element between the source and the converter. During faults, it provides a magnetic path that channels and limits fault currents through its air gap, preventing these harmful currents from directly reaching the converter while still allowing the converter to function during normal operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If switches with high fault current capacity are used to protect the converter, then converter protection is improved, but the cost of the regulator increases significantly

Engineering Contradiction:
Improveconverter protectionVSAvoidregulator cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the need for expensive high-capacity mechanical switches with a magnetic field-based protection mechanism. The saturable reactor formed by the third core uses magnetic saturation physics to automatically limit fault currents without requiring any moving parts or complex switchgear, significantly reducing system cost and complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The third core with its air gap provides automatic, self-regulating fault current limitation. When fault currents attempt to flow, the air gap causes magnetic saturation that inherently limits the current without requiring external control systems, expensive switches, or maintenance-intensive protection devices.

Inventive Principle:
Principle #25Self-service

3Reliability

If the converter is decoupled from the first coil during faults, then converter protection is improved, but voltage regulation capability is lost during the fault period

Engineering Contradiction:
Improveconverter protectionVSAvoidvoltage regulation availability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The magnetic coupling between the three cores is dynamic and automatically adapts to operating conditions. During normal operation, the cores are magnetically coupled to enable voltage regulation. During faults, the magnetic path automatically reconfigures through saturation, providing protection while maintaining the ability to quickly return to regulation mode once the fault is cleared.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The regulator effectively decouples the converter from the network during faults, protecting it from high currents and allowing for quick recovery to normal operation, reducing the need for expensive cut-off devices and maintaining voltage regulation without maintenance.

Implementation Method 1

a third decoupling core, and a virtual air gap, the virtual air gap comprising at least one pair of holes in the third decoupling core, and a winding winding between the holes of each pair of holes, and connected to a direct current source, the regulator operating between at least two states, namely: a first state in which the virtual air gap is opened by magnetically saturating the third decoupling core

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Implementation Method 2

In normal mode, that is to say without fault in the network, the magnetic flux F A of the first coil 1 closes in circuit 2 on the first core 21 and the second core 22.

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 3

a winding winding between the holes of each pair of holes, and connected to a direct current source

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2686746B1Series voltage regulator with electronics protected against short-circuits by magnetic circuit-based decoupling using holes and windows
Publication Date: 2015.04.22 ELECTRICITE DE FRANCE
  • EP2686746B1 patent drawingFigure 1
  • EP2686746B1 patent drawingFigure 2A~2B
  • EP2686746B1 patent drawingFigure 2C

AI summary

Voltage regulator (10), suitable for being connected in series between on the one hand an AC source (S) and on the other hand a load (C), comprising a magnetic circuit (2) comprising a first core (21) and a second core (22), at least one first inductive coil (2) coiled at least partially around the first core (21) and linked on the one hand to the AC source (S) and on the other hand to the load (C), and at least one voltage converter (4) comprising a second core (7) coiled around the second core (22), the regulator (10) being characterized in that the circuit (2) comprises a third decoupling core (3) and a virtual gap (EV), the virtual gap (EV) comprising at least one pair (50) of holes (5) in the third decoupling core (3), and a winding (6) wound between the holes (5) of each pair (50) of holes (5), and linked to a DC current source (8), the regulator (10) operating between at least two states.