DC/DC Converter Layout for Fast Solar-Battery Power Switching

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Solution Overview

Problem

Existing dual power systems, particularly in solar tracking systems, face inefficiencies and lag in switching between solar power and battery power to meet grid demands due to oversized inverters and communication delays, limiting their ability to respond quickly to changes in energy requirements.

Innovation Solution

A multi-power distributed storage system utilizing a single input port inverter and bi-directional DC/DC converters with a power droop algorithm, allowing for near instantaneous response to changes in load by managing battery banks and solar panels through a common bus, eliminating the need for additional communication and ensuring operation within the Maximum Power Point Tracking (MPPT) region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a multi-input port inverter is used to manage solar array and battery separately, then the system can meet large power requests from the grid, but the device complexity increases and communication delays limit fast response capability

Engineering Contradiction:
Improvepower request capabilityVSAvoidinverter and charger correlation complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent divides the power management function into separate independent modules: a solar charge controller managing the solar array and a battery charge controller managing the battery, both connected to a common DC bus. This segmentation eliminates the need for complex correlation between central inverter and battery charger, reducing system complexity while maintaining power management capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a common DC bus as an intermediary component that couples the solar array and battery independently to the inverter. This DC bus acts as a mediator that simplifies power flow management, eliminating the need for complex communication and coordination between solar and battery systems, thereby enabling fast response without communication delays.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the inverter is oversized to meet large power requests, then the power capability is improved, but the loss of energy increases due to inefficiency at partial load operation

Engineering Contradiction:
Improvemaximum power deliveryVSAvoidinverter efficiency at partial load
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent changes the operating parameters of the inverter by decoupling the solar and battery power sources through independent DC coupling. This allows the inverter to receive power from either source or both simultaneously, enabling it to operate at optimal efficiency points across varying load conditions while still meeting large power requests when needed.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic power management where the system can flexibly switch between solar power, battery power, or combined power based on real-time conditions. The independent DC coupling allows dynamic adjustment of power contribution from each source, optimizing inverter efficiency while maintaining the capability to deliver large power requests when required.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If communication is used to coordinate between central inverter and battery charger, then power management is achieved, but the response time increases due to communication delay

Engineering Contradiction:
Improvepower management coordinationVSAvoidresponse time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent enables each power source (solar array and battery) to independently manage its own power output through local charge controllers that directly interface with the common DC bus. This self-service approach eliminates the need for communication and coordination between central inverter and battery charger, allowing instantaneous response to power demands without communication delays.

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 solution enables fast and efficient switching between power sources, maintaining constant power output and optimizing energy transfer efficiency, even under varying sunlight conditions and changing load demands, thereby improving the responsiveness and efficiency of the energy grid.

Implementation Method 1

A multi-power distributed storage system utilizing a single input port inverter and bi-directional DC/DC converters

Methodology Applied
Scientific EffectElectrical energy conversion: Electromagnetic Induction

Implementation Method 2

managing battery banks and solar panels through a common bus

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP3785342B1DC/DC converter for distributed storage and solar systems
Publication Date: 2024.10.30 NEXTRACKER INC
  • EP3785342B1 patent drawingFigure 1
  • EP3785342B1 patent drawingFigure 2
  • EP3785342B1 patent drawingFigure 3

AI summary

A multi-power distributed storage system including a first power source; a second power source electrically connected to a common bus with the first power source; a single input port inverter electrically connected to the common bus. The system including a controller configured to communicate with at least the second power source, and the single input port inverter. The second power source including a plurality of battery banks and a plurality of bi-directional DC/DC converters configured to charge and discharge the plurality of battery banks and provide DC to the single input port inverter.