Four-Wire Solar Converter Segmentation for Grid Connection

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Solution Overview

Problem

Existing solar power converters with 3-wire grid-side connections fail to optimize voltage control and energy recapture due to uneven irradiance and increased costs associated with high voltage, and lack independence in controlling positive and negative bus currents.

Innovation Solution

A two-level converter with a four-wire connection allows separate determination of optimal voltage from positive and negative sub-arrays, enabling independent control of currents and reducing energy loss, while maintaining lower voltage component costs by supporting higher voltage photovoltaic arrays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If higher voltage photovoltaic arrays are used to increase power throughput, then power output is improved, but component costs increase due to higher voltage requirements

Engineering Contradiction:

Improvepower throughputVSAvoidcomponent costs

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The system segments the photovoltaic array into multiple strings connected in parallel, each string operating at a lower voltage. This allows the overall system to achieve high power throughput through increased current rather than requiring individual components to handle high voltages, thereby reducing component costs while maintaining power output

Inventive Principle:

Principle #1Segmentation

2Device complexity

If a single voltage is used for the solar array, then device complexity is reduced, but energy yield is lost due to uneven irradiance conditions

Engineering Contradiction:

Improvevoltage control complexityVSAvoidenergy yield

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The photovoltaic array is segmented into multiple independently controllable strings that can operate at different voltages. This segmentation enables each string to be optimized for its specific irradiance conditions, recapturing energy that would otherwise be lost, while the overall system complexity is managed through modular control architecture

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the operating voltage of each photovoltaic string based on real-time irradiance conditions. This dynamic adaptation allows the system to optimize energy capture under varying conditions without requiring overly complex static control mechanisms

Inventive Principle:

Principle #15Dynamics

3Device complexity

If a three-wire grid-side connection is used, then device complexity is reduced, but independence in controlling positive and negative bus currents is lost

Engineering Contradiction:

Improveconnection complexityVSAvoidcurrent control independence

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The grid connection is segmented into separate positive and negative bus control paths within the four-wire configuration. This segmentation enables independent control of positive and negative bus currents while maintaining a relatively simple overall connection structure, improving ease of operation for current management

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10700526B2Solar power converter with four-wire grid-side connection

Publication Date: 2020.06.30 GE ENERGY POWER CONVERSION TECHNOLOGY LTD(GB)

AI summary

There are provided methods and systems for interfacing converters and solar power arrays. For example, there is provided a method for interfacing a solar power generation apparatus with an electricity grid. The method can include connecting a first level and a second level of the solar power generation apparatus to a two-level converter. Furthermore, the method can include interfacing the two-level converter with the electricity grid via a four-wire connection.