Single Inverter Power Conversion System for Distributed Energy

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Solution Overview

Problem

The existing power conversion systems for combining created energy and stored energy result in increased installation costs, energy loss due to multiple inverters, space constraints, and the need for separate JET verification for each inverter, limiting flexibility in device configuration and energy usage efficiency.

Innovation Solution

A power conversion system comprising a DC conversion unit, a single inverter unit verified for connection to a commercial system, and a control unit that stabilizes voltage, allowing for efficient conversion and use of created and stored energy, with bidirectional inverter capabilities and independent control units to manage communication and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple photovoltaic inverters are installed for each distributed power supply, then each power source can be independently converted to AC power, but the installation cost increases and energy loss occurs in multiple inverters

Engineering Contradiction:
Improveindependent power conversionVSAvoidenergy loss in inverters
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent combines multiple DC power sources (photovoltaic panels, storage batteries, fuel batteries) into a single DC bus, then uses one shared inverter to convert all DC power to AC power. This merging approach eliminates the need for multiple separate inverters, reducing energy loss while maintaining reliable power conversion for each source through individual DC/DC conversion stages.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple photovoltaic inverters are installed for each distributed power supply, then each power source can be independently converted to AC power, but the installation cost increases

Engineering Contradiction:
Improveindependent power conversionVSAvoidinstallation cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple power conversion functions into a single inverter unit that serves all DC power sources. By sharing one inverter among multiple DC/DC converters, the system reduces component count and installation cost while maintaining independent control and conversion capability for each power source through the DC bus architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared inverter is designed to handle multiple DC power sources simultaneously, making it a universal device that can convert AC power for photovoltaic panels, storage batteries, and fuel batteries. This multi-functional approach eliminates the need for separate dedicated inverters for each power source, reducing overall system cost.

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

3Reliability

If multiple photovoltaic inverters are installed for each distributed power supply, then each power source can be independently converted to AC power, but the space required for installation increases

Engineering Contradiction:
Improveindependent power conversionVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent consolidates multiple inverter functions into a single physical unit, dramatically reducing the space required for installation. By sharing one inverter among multiple DC power sources through the DC bus, the system eliminates redundant equipment and minimizes installation footprint while preserving independent power conversion capability.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If each photovoltaic inverter is interconnected with the system and requires JET verification, then system safety is ensured, but the verification process becomes complex and time-consuming

Engineering Contradiction:
Improvesystem safetyVSAvoidJET verification complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple JET verification requirements into a single verification process for the shared inverter. Since only one inverter is used instead of multiple separate inverters, the system needs to obtain JET verification only once, significantly simplifying the certification process while maintaining system safety through the verified inverter unit.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces energy loss, minimizes space requirements, and simplifies JET verification by using a single inverter unit, enhancing the flexibility and efficiency of energy usage while ensuring stable voltage and communication integrity.

Implementation Method 1

a DC conversion unit (111 to 115), each corresponding to the distributed power supplies (10), respectively. The DC conversion unit (111 to 115) converts an output of each of the distributed power supplies (10) into DC power

Methodology Applied
Scientific EffectPower conversion:

Implementation Method 2

a single inverter unit (121). The inverter unit (121) converts DC power of the bus line into AC power

Methodology Applied
Scientific EffectInversion conversion:

Implementation Method 3

a control unit (131 to 135). The control unit (131 to 135) stabilizes voltage of the bus line

Methodology Applied
Scientific EffectVoltage stabilization:

Data Source

PatentEP3089310B1Power conversion system, converter device, inverter device, and power conversion system manufacturing method
Publication Date: 2019.09.25 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3089310B1 patent drawingFigure 1
  • EP3089310B1 patent drawingFigure 2
  • EP3089310B1 patent drawingFigure 3

AI summary

A power conversion system (20) comprises: a DC conversion unit (21) for converting each of the outputs of a plurality of distributed power supplies (10) to DC power and outputting the DC power to a bus line; a single inverter unit (22) having an authentication for connecting to a commercial power grid (70) and converting the DC power on the bus line to AC power and supplying the AC power to a load and the commercial power grid (70); and a control unit (23) for stabilizing the voltage on the bus line.