PV-Coupled Battery Rack Control With Distributed DC/DC Converters

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Solution Overview

Problem

Existing DC-coupled energy storage systems face challenges in controlling individual battery racks and require appropriate control methods when integrated with photovoltaic systems, as they lack the ability to manage power conversion efficiently and individually control battery components.

Innovation Solution

The system includes a power management controller that determines operating modes and output references for a power conversion system and DC/DC converters based on the state of the photovoltaic system, using MPPT and droop modes to optimize power management, and a battery section controller to manage individual battery racks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a large-capacity central power converter (DC/DC converter) is applied in a DC-coupled system, then power conversion capability is improved, but individual control of battery racks becomes impossible

Engineering Contradiction:
Improvepower conversion capabilityVSAvoidindividual control of battery racks
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent divides the single central power converter into multiple distributed power converters, each associated with individual battery racks. This segmentation enables both adequate power conversion capability and individual control of each battery rack, as each converter can be independently controlled while collectively meeting the system's power requirements.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If a power management system monitors state of each component in a DC-coupled system, then system monitoring capability is improved, but appropriate control method for photovoltaic integration is lacking

Engineering Contradiction:
Improvesystem monitoring capabilityVSAvoidcontrol method for photovoltaic integration
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic control strategies that adapt to different operating conditions of the photovoltaic system. The power management system dynamically adjusts control parameters and modes based on real-time monitoring of photovoltaic output, battery states, and grid conditions, enabling appropriate control methods for photovoltaic integration while maintaining precise system monitoring.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If DC-coupled system architecture is used with photovoltaic system, then system efficiency is improved, but control complexity increases

Engineering Contradiction:
Improvesystem efficiencyVSAvoidcontrol complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent enables the DC-coupled system to self-regulate through coordinated control of distributed power converters that automatically adjust their operation based on local measurements and system-wide communication. This self-service capability maintains high efficiency while reducing external control complexity, as the system components autonomously manage power flow based on real-time conditions.

Inventive Principle:
Principle #25Self-service

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 approach allows for efficient control and operation of individual battery racks in the energy storage system, enhancing system efficiency and flexibility in response to photovoltaic system conditions.

Implementation Method 1

An energy storage system connected with a PV (Photovoltaic) system

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

a plurality of DC/DC converters configured to control a plurality of battery racks

Methodology Applied
Scientific EffectElectrical energy conversion:

Implementation Method 3

a plurality of battery racks

Methodology Applied
Scientific EffectElectrochemical energy storage: Battery (electricity)

Data Source

PatentEP4293852B1Energy storage system associated with solar system and method for controlling energy storage system
Publication Date: 2025.10.29 LG ENERGY SOLUTION LTD
  • EP4293852B1 patent drawingFigure 1
  • EP4293852B1 patent drawingFigure 2
  • EP4293852B1 patent drawingFigure 3

AI summary

An energy storage system, connected with a photovoltaic system and a power grid, may comprise: a plurality of DC/DC converters configured to control a plurality of battery racks; a power conversion system configured to control power in connection with the plurality of DC/DC converters and the photovoltaic system; and a power management controller configured to determine operating modes and output references of the power conversion system and the plurality of DC/DC converters according to a state of the photovoltaic system.