Hybrid AC DC Distribution System for Variable Speed Generator Efficiency

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Solution Overview

Problem

Existing electrical power distribution systems for islanded systems, such as those on marine ships, face inefficiencies due to the need for multiple conversions between AC and DC power, leading to increased electronic components and reduced operational efficiency, especially under variable load conditions.

Innovation Solution

A hybrid AC and DC distribution system utilizing a doubly fed induction generator (DFIG) with parallel AC and DC distribution buses, along with AC-to-DC and DC-to-AC converters, reduces the number of electronic components and allows for variable speed engine operation to match real-time loads, improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple AC-to-DC and DC-to-AC converters are used to supply different load types, then all loads can be powered, but the number of electronic components increases and efficiency decreases

Engineering Contradiction:

Improveability to supply different load typesVSAvoidnumber of electronic components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple power conversion functions into a single hybrid AC/DC distribution system architecture. The system merges AC and DC distribution buses and integrates multiple load supply capabilities into one unified system, reducing the need for separate converters for each load type while maintaining the ability to serve diverse electrical loads efficiently

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple AC-to-DC and DC-to-AC converters are used for power conversion, then different load types can be supplied, but operational efficiency is reduced

Engineering Contradiction:

Improveability to supply different load typesVSAvoidoperational efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The hybrid distribution system merges AC and DC power paths into a unified architecture, reducing the number of sequential power conversions required. By providing both AC and DC distribution buses, the system eliminates redundant conversion steps and minimizes energy losses associated with multiple AC-to-DC and DC-to-AC conversions while maintaining adaptability to different load types

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If generators operate at fixed frequency to match AC distribution bus requirements, then AC loads can be supplied, but generators cannot operate at peak efficiency under variable load conditions

Engineering Contradiction:

Improveability to supply AC loadsVSAvoidgenerator operating efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent implements a dynamic hybrid AC/DC distribution system where the generator can operate at variable speeds and frequencies optimized for peak efficiency under different load conditions. The system dynamically adjusts power distribution between AC and DC buses based on real-time load requirements, allowing the generator to operate in its most efficient range while still meeting diverse electrical load demands

Inventive Principle:

Principle #15Dynamics

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

The system achieves improved efficiency and reduced operational costs by minimizing electronic components and optimizing power generation and load matching, resulting in lower capital expenditures and enhanced power delivery for variable loads.

Implementation Method 1

an AC-to-DC converter coupled to said rotor and further coupled to said DC distribution bus at a first node, said AC-to-DC converter configured to convert the first AC power to a first DC power at the first node for delivery through said DC distribution bus

Methodology Applied

Scientific EffectAC-to-DC conversion:

Implementation Method 2

a DC-to-AC converter coupled between the first node and a second node, the second node coupled to said stator and said AC distribution bus, said DC-to-AC converter configured to convert the first DC power to the second AC power for delivery to said stator and through said AC distribution bus

Methodology Applied

Scientific EffectDC-to-AC conversion:

Implementation Method 3

a doubly fed induction generator (DFIG) comprising a rotor and a stator, said DFIG configured to generate a first AC power at said rotor and a second AC power at said stator

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3098923B1Hybrid ac and DC distribution system

Publication Date: 2020.07.01 ABB (SCHWEIZ) AG

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AI summary

A hybrid AC and DC distribution system (200) includes a doubly fed induction generator (DFIG) (204;504), a DC distribution bus (214), an AC/DC converter (218;506), an AC distribution bus (216), and a DC/AC converter (220;508). The DFIG includes a rotor (224) and a stator (226), and is configured to generate a first AC power at the rotor and a second AC power at the stator. The AC/DC converter (218;506) is coupled to the rotor and the DC distribution bus (214). The AC/DC converter (218;506) converts the first AC power to a first DC power at a first node (228;510) for delivery to a first load (206,210) through the DC distribution bus. The DC/AC converter is coupled between the first node and a second node (230;512) coupled to the stator (226) and the AC distribution bus (216). The DC/AC converter converts the first DC power to the second AC power at the second node (230;512) for delivery to a second load (206,208) through the AC distribution bus (216).