Energy Management Unit for AC Grid Stability

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Solution Overview

Problem

The variability in energy production from renewable sources like photovoltaic and wind power plants leads to fluctuations in electrical energy supply, resulting in excess or deficit energy in the energy consumption and supply networks, necessitating an efficient energy management system to store and regulate energy accordingly.

Innovation Solution

An energy management unit that includes a control and regulation system, a first inverter for converting DC energy from renewable sources to AC energy, a second DC/DC converter for storing excess energy in an energy store, and a third AC/DC converter for drawing energy from the AC network, allowing for seamless integration with existing inverters and energy storage systems without requiring additional DC/AC conversion devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If energy converters (photovoltaic/wind power plants) are used to generate electrical energy from renewable sources, then energy production from renewable sources is improved, but energy supply stability deteriorates due to strong fluctuations in generation

Engineering Contradiction:
Improveenergy supply stabilityVSAvoidenergy generation consistency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The energy store is charged in advance during periods of excess energy generation from renewable sources, preparing stored energy for future use when generation is insufficient. This preliminary energy storage action smooths out the fluctuations in renewable energy supply and ensures stable energy availability.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If excess electrical energy from energy converters is stored in an energy store, then energy storage capability is improved, but system complexity increases due to additional conversion devices

Engineering Contradiction:
Improvestored energy capacityVSAvoidsystem structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The inverter is designed to perform multiple functions: it converts DC energy from energy converters to AC energy for the grid, and also manages bidirectional energy flow between the energy store and the AC energy consumption grid. This multi-functionality eliminates the need for separate dedicated conversion devices for storage operations, reducing overall system complexity.

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

Solution Approach 2:

The patent combines the energy conversion and energy management functions into a single integrated inverter system that handles both grid connection and energy store management. By merging these functions, the system avoids the complexity of multiple separate conversion devices while maintaining full capability for excess energy storage and deficit energy supply.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If a bidirectional DC/DC converter is configured upstream of the inverter for charging/discharging the energy store, then energy management flexibility is improved, but device complexity increases

Engineering Contradiction:
Improveenergy management flexibilityVSAvoidconverter configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The inverter is designed to perform multiple functions: it converts DC energy from energy converters to AC energy for the grid, and also manages bidirectional energy flow between the energy store and the AC energy consumption grid. This multi-functionality eliminates the need for separate dedicated conversion devices for storage operations, reducing overall system complexity.

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

4Reliability

If the inverter is controlled to prevent unfavorable current and voltage constellations, then system reliability is improved, but control complexity increases

Engineering Contradiction:
Improvesystem stabilityVSAvoidcontrol unit functionality
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit continuously monitors current and voltage conditions in the system and adjusts the inverter operation accordingly. This feedback control prevents unfavorable current and voltage constellations by detecting potential issues and correcting them in real-time, ensuring system reliability while maintaining manageable control complexity through automated regulation.

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

This solution enables efficient storage and retrieval of energy, maintaining energy balance in the AC energy consumption grid, allowing for the use of existing inverters and simplifying the integration of energy storage systems, thus ensuring reliable energy supply without the need for specialized DC/AC conversion devices.

Implementation Method 1

a first inverter (13) for converting DC energy from renewable sources to AC energy

Methodology Applied
Scientific EffectDC to AC conversion:

Implementation Method 2

a second DC/DC converter (22) for storing excess energy in an energy store (40)

Methodology Applied
Scientific EffectEnergy storage: Accumulator (energy)

Implementation Method 3

a third AC/DC converter (42) for drawing energy from the AC network

Methodology Applied
Scientific EffectAC to DC conversion:

Data Source

PatentEP3472909B1Energy management unit, energy supply system and energy management method
Publication Date: 2022.12.14 KARLSRUHER INST FUR TECH
  • EP3472909B1 patent drawingFigure 1
  • EP3472909B1 patent drawingFigure 2a
  • EP3472909B1 patent drawingFigure 2b

AI summary

One aspect relates to an energy management unit 10 for controlling and/or regulating energy provision in an AC energy consumption network (300) with the aid of an energy store (40) on the basis of an energy requirement state of the AC energy consumption network (300), wherein the AC energy consumption network (300) is connected to a DC energy generation network (100) via an inverter (13), comprising: - a DC/DC converter (22) for supplying energy taken from the energy store (40) to the DC energy generation network (100); - an AC/DC converter (42) for storing energy taken from the AC energy consumption network (300) in the energy store (40); and - a control and/or regulation unit (30) which is designed: - to determine the energy requirement state of the AC energy consumption network (300); and - to control and/or regulate the DC/DC converter (22) and the AC/DC converter (42) on the basis of the determined energy requirement state.