Aircraft DC Bus Synchronization for Load Sharing and Isolation

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Solution Overview

Problem

Aircraft electrical systems face inefficiencies due to the need for multiple generators and redundant distribution channels, which increase weight, fuel consumption, and reduce overall system efficiency, especially when prime movers operate at varying speeds to meet high electrical power demands.

Innovation Solution

The implementation of a DC power distribution system utilizing multiple generators driven by different engine spools, with AC/DC converters and dedicated DC buses, and a synchronization bus that allows for dynamic power sharing and isolation through intelligent control algorithms, optimizing power generation and distribution based on aircraft operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple generators are employed to meet high electrical power demands, then power generation capability is improved, but system complexity and weight increase

Engineering Contradiction:
Improveelectrical power generation capabilityVSAvoidsystem complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent makes the distribution system universal by enabling each dedicated DC bus to serve dual purposes: isolated operation for fault containment and synchronized operation for load sharing. The synchronization bus allows any generator to supply power to any bus, creating a multi-functional system that adapts to different operational requirements without adding permanent complexity.

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

Solution Approach 2:

The system dynamically reconfigures its topology through controllable switches that can open or close based on operational conditions. During normal operation, buses operate in isolation; during high demand or fault conditions, the synchronization bus dynamically connects multiple generators to share the load, allowing the system complexity to adapt to the actual power needs rather than being permanently fixed at maximum complexity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If redundant distribution channels are used to ensure fault tolerance, then system reliability is improved, but overall system efficiency decreases

Engineering Contradiction:
Improvefault toleranceVSAvoidsystem efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The synchronization bus is pre-configured but remains open during normal operation, providing a ready-made fault tolerance mechanism that doesn't interfere with efficient isolated operation. When a fault occurs or high power demand arises, the bus can be quickly closed to provide backup power paths, cushioning against failures without permanently reducing efficiency.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Power

If prime movers are operated at higher speeds to meet generator load demands, then electrical power output is improved, but fuel consumption increases

Engineering Contradiction:
Improveelectrical power outputVSAvoidfuel consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent merges the output capabilities of multiple generators through the synchronization bus, combining their power outputs to meet high electrical demands. This allows the system to achieve high power output by coordinating multiple prime movers operating at efficient speeds rather than forcing a single prime mover to operate at high speed and high fuel consumption.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of operating all generators at full capacity continuously, the system uses partial action by activating and synchronizing only the necessary number of generators based on actual power demand. This prevents excessive fuel consumption by avoiding unnecessary operation of generators at speeds higher than required for their primary propulsion function.

Inventive Principle:
Principle #16Partial or excessive action

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 approach enhances power generation capability, fault tolerance, and efficiency by dynamically allocating power between generators, reducing horsepower extraction from high-pressure spools and minimizing fuel consumption, while maintaining reliable operation and adhering to Mil-Std-704F power quality standards.

Implementation Method 1

a plurality of AC/DC converters that each receive a respective AC output signal from a respective generator and generate a respective DC voltage

Methodology Applied
Scientific EffectAC/DC conversion:

Data Source

PatentEP3304674B1Aircraft DC power distribution systems and methods
Publication Date: 2024.12.18 NORTHROP GRUMMAN SYSTEMS CORP
  • EP3304674B1 patent drawingFigure 1
  • EP3304674B1 patent drawingFigure 2
  • EP3304674B1 patent drawingFigure 3

AI summary

Systems and methods are provided for distributing DC power in an aircraft. In one example, a method is provided that includes generating a plurality of DC voltages from a plurality of independent sources driven by one or more turbines of the aircraft, providing each of the plurality of DC voltages to respective dedicated DC buses, and setting a plurality of switches that selectively couples a first set of dedicated DC buses to a synchronization bus to allow for bus sharing between the first set of dedicated DC buses and bus isolation of a second set of dedicated DC buses.