Multicell Power Converter for HVDC-AC Conversion

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Solution Overview

Problem

Existing high voltage power conversion technologies lack flexibility and efficiency, particularly in handling power conversions between DC and AC, and require additional components to manage voltage ripple.

Innovation Solution

A power converter design featuring multiple converter arms with passive and active components, capacitors, and transformers that allow bidirectional power flow between high voltage DC and AC connections, reducing the need for external control and additional components by using adaptive converter arms that detect AC components and harmonize power conversion between DC and AC.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a power converter is designed to handle power conversions between DC and AC connections, then flexibility is improved, but additional components are required to manage voltage ripple and control

Engineering Contradiction:
ImproveflexibilityVSAvoidcomponent requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The converter arms are designed to perform multiple functions: they can connect between DC connections, between AC connections, or between DC and AC connections. The same converter arm structure handles both power conversion and voltage ripple management, eliminating the need for separate dedicated components for each function.

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

Solution Approach 2:

The patent combines the power conversion function and voltage ripple management function into the same converter arms. The capacitors and inductors that are part of the converter arm structure simultaneously perform energy storage for power conversion and filtering for voltage ripple reduction, reducing overall component count.

Inventive Principle:
Principle #5Merging (Combining)

2Extent of automation

If converter arms use passive and active components for adaptive control, then external control requirements are reduced, but device complexity increases

Engineering Contradiction:
Improveadaptive controlVSAvoidconverter arm structure
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The converter arms are equipped with capacitors and inductors that enable them to automatically detect AC components and harmonize power conversion without requiring external control signals. The passive components (capacitors and inductors) provide automatic voltage ripple filtering and adaptive response to changing operating conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The converter arms use the electrical characteristics detected through their passive and active components to automatically adjust their operation. The capacitors and inductors provide real-time feedback on voltage and current conditions, enabling the converter arms to adaptively control power flow and maintain stable operation.

Inventive Principle:
Principle #23Feedback

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 solution provides increased flexibility and reduced component requirements, effectively managing voltage ripple and enabling efficient power conversion between high voltage DC and AC connections with minimal external control, while allowing bidirectional power flow.

Implementation Method 1

The power converter may further comprise a first pair of capacitors arranged between the two terminals of the first high voltage DC connection and a second pair of capacitors arranged between the first terminal of the second high voltage DC connection and the second terminal of the second high voltage DC connection. This reduces voltage ripple on the first and second high voltage connections.

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The power converter may further comprise a first transformer between the high voltage AC connection and the third connection point and a second transformer between the high voltage AC connection and the fourth connection point. The transformer allows for a voltage conversion and will also provide electrical insulation.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2781014B1Ac/DC multicell power converter for dual terminal HVDC connection
Publication Date: 2015.11.11 ABB TECHNOLOGY AG
  • EP2781014B1 patent drawingFigure 1
  • EP2781014B1 patent drawingFigure 2A~3B
  • EP2781014B1 patent drawingFigure 4A~5

AI summary

It is presented a power converter for converting power between a first high voltage direct current, DC, connection, a second high voltage DC connection and a high voltage alternating current, AC, connection. The power converter comprises: a first phase arrangement comprising a first converter arm, a second converter arm, a third converter arm, a fourth converter arm, a fifth converter arm and a sixth converter arm. The first, second third and fourth converter arms are serially connected in the mentioned order between two terminals of the first high voltage DC connection. The high voltage AC connection is connected between the second converter arm and the third converter arm.