Shared Return Path for Hybrid Vehicle Electrical Systems

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Solution Overview

Problem

Conventional aircraft electrical systems face challenges in providing an effective current return path for high voltage propulsive loads, especially in hybrid electric aircraft with composite structures, as they require shielding and cannot use the aircraft body, leading to weight, cost, and complexity issues.

Innovation Solution

The second electrical distribution system, designed for high voltage operations above 1000V DC or RMS AC, provides a return path that also serves the first electrical distribution system operating below 1000V DC or RMS AC, eliminating the need for a separate return path in areas where the second system is present, thereby optimizing weight and space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate return path is provided for the first electrical distribution system (low voltage), then the low voltage system has reliable current return, but the weight, cost and complexity of the electrical interconnect system increases

Engineering Contradiction:

Improvecurrent return path reliabilityVSAvoidweight of electrical interconnect system

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The return path of the second electrical distribution system (high voltage) is designed to serve dual purposes: it functions as the return path for high voltage currents and simultaneously serves as the return path for low voltage currents from the first electrical distribution system. This multi-functional approach eliminates the need for a separate dedicated return path for low voltage systems, thereby reducing weight while maintaining reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the return path infrastructure of the high voltage and low voltage electrical distribution systems into a single shared pathway. By combining these functions into one common return path structure, the system avoids duplicating conductive pathways, resulting in significant weight savings and reduced system complexity while ensuring both voltage levels have adequate current return capability.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If shielding is provided for the first electrical distribution system to prevent arcing, then the high voltage system is protected, but the device complexity and cost increases

Engineering Contradiction:

Improvearc preventionVSAvoidcomplexity of electrical interconnect system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The shielding structure of the second electrical distribution system (high voltage) is configured to provide protective coverage for the first electrical distribution system (low voltage) as well. This universal shielding approach allows a single shielding infrastructure to protect against arcing for both voltage levels, thereby preventing arcs without requiring separate shielding systems for each voltage level, thus reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Weight of stationary object

If a common current return path through the aircraft body is used, then the structure provides electrical pathways, but this is inadequate for high voltage systems due to shielding requirements

Engineering Contradiction:

Improveuse of aircraft structureVSAvoidhigh voltage current return adequacy

Core Design Contradiction:

Weight of stationary objectVSReliability

Solution Approach 1:

The electrical distribution system is segmented into two distinct voltage levels: a first electrical distribution system operating at low voltage (below 1000V) that can utilize the aircraft body as a common current return path, and a second electrical distribution system operating at high voltage (above 1000V) that has its own dedicated return path and shielding. This segmentation allows each system to operate with appropriate return path characteristics for its voltage level.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second electrical distribution system acts as an intermediary solution that provides both high voltage power distribution and a dedicated return path with shielding. This intermediary high voltage system enables the low voltage first electrical distribution system to safely use the aircraft body as a common current return path, since the high voltage system's shielding and dedicated return path prevent interference and arcing issues that would otherwise prevent such shared usage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3462563B1Electrical interconnect system of a vehicle

Publication Date: 2020.09.02 ROLLS ROYCE PLC

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AI summary

The present disclosure concerns an electrical interconnect system for a vehicle such as an aircraft or marine/submarine vessel. Example embodiments include a vehicle (400) comprising: a first electrical generator (404); a second electrical generator (405); an engine (403) arranged to drive the first and second electrical generators (404, 405); a first electrical distribution system connected to the first electrical generator (404) and arranged to distribute electrical power within the vehicle (400), the first electrical distribution system comprising a transmission path (401) and a return path (402); a second electrical distribution system (407) connected to the second electrical generator (405), the second electrical distribution system (407) comprising a transmission path and a return path; an electric motor (406) configured to provide propulsion for the vehicle (400) and connected to the second electrical generator (405) via the second electrical distribution system (407), wherein the return path of the second electrical distribution system (407) provides a portion of the return path of the first electrical distribution system.