Marine DC Bus Architecture With Independent Generator Winding Sets

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Solution Overview

Problem

Conventional marine vessel power systems using multiple DC buses face challenges with complex bus-ties for handling DC fault currents, leading to increased costs, weight, and size due to the need for larger busbars and complex control systems, as well as reduced redundancy and potential safety risks.

Innovation Solution

A power system utilizing a generator with multiple winding sets, each connected to a separate DC bus, eliminating the need for a bus-tie and providing redundancy by allowing the generator to continue powering one bus in case of a fault on the other, while using switching elements and battery assemblies for fault management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If bus-ties are used to electrically tie DC buses together, then power sources can be shared among buses, but the system complexity increases due to complex algorithms required for handling DC fault currents

Engineering Contradiction:
Improvepower sharing capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The generator is segmented into multiple independent winding sets, with each winding set connected to a separate DC bus. This segmentation eliminates the need for bus-ties and complex control algorithms, as each winding set independently powers its associated bus without requiring coordination with other buses.

Inventive Principle:
Principle #1Segmentation

2Reliability

If bus-ties are used to handle fault situations, then safety is improved, but the response time is reduced due to the difficulty of interrupting DC fault currents without natural zero-point crossings

Engineering Contradiction:
Improvefault handling safetyVSAvoidfault response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

By segmenting the generator into independent winding sets connected to separate DC buses, fault isolation becomes inherent to the system architecture. When a fault occurs on one bus, it automatically affects only the corresponding winding set, eliminating the need for complex bus-tie disconnection algorithms and enabling immediate fault response.

Inventive Principle:
Principle #1Segmentation

3Power

If bus dimensions are increased to handle large DC fault currents, then the current carrying capacity is improved, but the weight and build-volume increase

Engineering Contradiction:
Improvefault current capacityVSAvoidbus weight
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The generator is segmented into multiple independent winding sets, each connected to a separate DC bus. This segmentation allows each bus to be dimensioned for its specific load requirements rather than being oversized to handle total system fault currents, significantly reducing bus weight and volume while maintaining adequate fault current handling capability for each individual bus.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If a single generator powers multiple buses through bus-ties, then cost is reduced, but the redundancy is worsened as a failure on one bus risks disconnecting the generator from other buses

Engineering Contradiction:
Improvesystem costVSAvoidsystem redundancy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The generator is segmented into multiple independent winding sets, each directly connected to a separate DC bus. This provides true redundancy where a failure on one bus does not affect other buses, as each winding set operates independently. The cost remains low since a single generator unit is used, but the architectural segmentation delivers the redundancy benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each winding set acts as an intermediary between the generator rotor and the DC buses, providing galvanic isolation and independent power paths. This intermediary structure ensures that faults on one bus cannot propagate to other buses through the generator, maintaining system redundancy while using a single generator unit.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the complexity and cost of the power system, minimizes weight and size, and enhances redundancy, enabling safe and efficient power distribution without the need for complex bus-tie mechanisms and maintaining power delivery during faults.

Implementation Method 1

The generator (250) includes at least a first winding set (251a) connected to power a first direct current (DC) bus (210a), and a second winding set (251b) connected to power a second DC bus (210b)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4235995A1A power system for electrical power generation and distribution
Publication Date: 2023.08.30 VOLVO PENTA AB
  • EP4235995A1 patent drawingFigure 1A~1B
  • EP4235995A1 patent drawingFigure 2A~2B
  • EP4235995A1 patent drawingFigure 2C~3

AI summary

A power system (200, 201) for electrical power generation and distribution in a marine vessel (300) is provided. The system includes a first direct current, DC, bus (210a) configured for powering a first load (in form of a first electrical propulsion machine 222a), and a second DC bus (210b) configured for powering a second load (in form of a second electrical propulsion machine 222b). The system further includes a generator (250) which includes at least a first winding set (251a) and a second winding set (251b). The first winding set is connected to power the first DC bus and the second winding set is connected to power the second DC bus. A marine vessel (300) including such a power system (200, 201) is also provided.