Hybrid Transformer With Multilevel Converter for Voltage and VAR Control

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Solution Overview

Problem

Existing grid-edge solutions for voltage volatility, such as stand-alone voltage or VAR injection, are bulky, expensive, and inefficient, and existing transformer systems lack simultaneous control of voltage and VAR injection capabilities.

Innovation Solution

A hybrid transformer system comprising a multi-level converter and controller that allows for simultaneous control of voltage injection and VAR injection on the high-voltage winding of an electrical voltage transformer, using a fail-normal switch to manage insulation and fault currents, eliminating the need for complex cooling systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stand-alone voltage or VAR injection solutions are used, then voltage volatility can be addressed, but the system becomes large, bulky, and expensive

Engineering Contradiction:
Improvevoltage volatility mitigationVSAvoidsystem size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines voltage injection and VAR injection capabilities into a single integrated hybrid transformer system. The converter is coupled to the transformer to provide both series voltage injection and shunt VAR injection simultaneously, eliminating the need for separate stand-alone voltage injection devices and separate VAR injection devices, thus reducing system size and complexity while maintaining voltage volatility mitigation capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hybrid transformer system is designed to perform multiple functions: it can provide series voltage injection for voltage regulation, shunt VAR injection for reactive power compensation, and both simultaneously. This multi-functional design replaces multiple specialized devices with a single universal system, addressing voltage volatility without increasing system bulk

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If stand-alone voltage or VAR injection solutions are used, then voltage control can be achieved, but the system becomes expensive

Engineering Contradiction:
Improvevoltage control capabilityVSAvoidsystem cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges voltage injection and VAR injection functions into a single hybrid transformer system with one converter, reducing the total number of components compared to using separate stand-alone voltage injection devices and VAR injection devices. This consolidation lowers material costs, installation costs, and maintenance costs while maintaining full voltage control capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hybrid transformer system provides universal voltage control capability by integrating both series voltage injection and shunt VAR injection in one system. This eliminates the need to purchase and install multiple specialized devices, thereby reducing overall system cost while achieving comprehensive voltage control

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system achieves efficient, low-loss, and cost-effective voltage and VAR injection, meeting insulation and fault current requirements while reducing system complexity and size.

Implementation Method 1

the converter is configured to control voltage injection and VAR injection to the high-voltage winding of the electrical voltage transformer

Methodology Applied
Scientific EffectVoltage injection:

Implementation Method 2

the converter is configured to control voltage injection and VAR injection to the high-voltage winding of the electrical voltage transformer

Methodology Applied
Scientific EffectVAR injection:

Implementation Method 3

an electrical voltage transformer (110) comprising a high-voltage winding (101)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3596743B1Hybrid transformer systems and methods
Publication Date: 2026.01.14 GEORGIA TECH RES CORP
  • EP3596743B1 patent drawingFigure 1a
  • EP3596743B1 patent drawingFigure 1b
  • EP3596743B1 patent drawingFigure 1c

AI summary

Embodiments of the present disclosure can include a hybrid transformer system comprising an electrical voltage transformer comprising: a high-voltage winding, the high-voltage winding comprising a first end and a second end, the first end having a lower voltage than the second end; a plurality of taps disposed proximate the first end of the high-voltage winding; a multi-level converter coupleable to the plurality of taps of the electrical voltage transformer, the multi-level converter configured to simultaneously control voltage injection and VAR injection to the high-voltage winding of the electrical voltage transformer; and a controller electrically coupleable to the multi-level converter, such that when the multi-level converter is coupled to the plurality of taps of the electrical voltage transformer, the controller is configured to selectively inject at least one of VARs or voltage to the high-voltage winding of the electrical voltage transformer.