Backup Power Unit With Decoupling Chokes for Grid-Forming Inverters

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Solution Overview

Problem

Existing backup power systems struggle to efficiently provide grid-forming electrical power when disconnected from the AC-grid, as conventional inverters designed for grid-following operation lack the necessary hardware and control mechanisms for autonomous grid-forming capabilities.

Innovation Solution

A backup power system with an electrical unit that includes decoupling chokes and a central control unit, enabling inverters originally designed for grid-following to operate in parallel and provide grid-forming power by integrating decoupling chokes and an overlaying control scheme, allowing them to autonomously supply loads in islanded microgrids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a battery backup system is integrated into an electrical unit, then power continuity is ensured during mains failure, but device complexity and cost increase

Engineering Contradiction:
Improvepower continuityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the battery backup system with the electrical unit by integrating the battery into the housing and sharing common components such as the terminal block, circuit board, and mounting structures. This merging approach ensures power continuity while avoiding the need for separate backup power systems, thereby reducing overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electrical unit is designed to perform multiple functions: it operates as a standalone device during normal operation and automatically switches to battery power during mains failure. The terminal block and circuit board serve dual purposes for both mains power connection and battery connection, eliminating the need for separate dedicated components for each power source.

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

2Volume of moving object

If a battery is integrated into the housing, then space utilization is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvespace utilizationVSAvoidmanufacturing complexity
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The housing is divided into distinct sections: a first section for receiving the battery and a second section for other components. This segmentation allows the battery to be independently installed and replaced without affecting other components, simplifying the manufacturing process while maximizing space utilization within the housing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The battery is nested within the housing structure, with the terminal block and circuit board positioned to accommodate both mains power connections and battery connections. This nested arrangement optimizes space utilization by placing components within the available internal volume of the housing without requiring additional external space.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If the terminal block is configured for both mains power and battery connection, then component count is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecomponent countVSAvoidterminal block precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The terminal block is designed as a universal component that accepts both mains power connections and battery connections through the same structural interface. This multi-functional design reduces the total component count by eliminating the need for separate terminal blocks for each power source, while the standardized connection points maintain manageable manufacturing precision requirements.

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

Data Source

PatentEP4342051B1Electrical unit and backup power system
Publication Date: 2026.04.29 SMA SOLAR TECH AG
  • EP4342051B1 patent drawingFigure 1
  • EP4342051B1 patent drawingFigure 2
  • EP4342051B1 patent drawingFigure 3

AI summary

Disclosed is an electrical unit with a first port configured to be operatively connected to an AC-grid, a second port configured to be operatively connected to an AC-load, and a third port to be operatively connected to an AC-side of a first inverter. The electrical unit includes a first choke arranged between the third port and the second port. The electrical unit is configured to transfer electrical power provided by the first inverter from the third port via the first choke to the second port. The electrical unit is configured to provide grid-forming electrical power to the second port in case of disconnection from the AC-grid at the first port. Further disclosed is a backup power system and a method for operating a backup power system.