Distributed Bus Voltage Control via Autonomous Droop

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Solution Overview

Problem

Existing electrical power systems face challenges in managing energy resources connected to a bus, particularly in maintaining stable voltage levels across different operating modes without extensive communication and with fewer and smaller capacitors, which is crucial for aerospace applications.

Innovation Solution

A system with distributed energy resources, including power sources, energy storage devices, and loads, is controlled using autonomous primary controllers that implement droop power curves and receive set points from a system controller, allowing for quick responses to disturbances and seamless mode transitions without centralized coordination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If distributed autonomous primary controllers with droop power curves are used, then response speed to disturbances is improved, but system complexity increases

Engineering Contradiction:

Improveresponse speedVSAvoidsystem complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

Each primary controller autonomously implements droop power curve control based on locally sensed parameters without requiring centralized coordination. The controllers self-regulate power flow by detecting local voltage and frequency deviations, enabling fast response to disturbances while maintaining distributed autonomy and avoiding complex centralized communication infrastructure.

Inventive Principle:

Principle #25Self-service

2Weight of stationary object

If fewer and smaller capacitors are used, then system size and weight are reduced, but voltage stability becomes more difficult to maintain

Engineering Contradiction:

Improvesystem weightVSAvoidvoltage stability

Core Design Contradiction:

Weight of stationary objectVSStability of the object's composition

Solution Approach 1:

The system employs feedback control through droop power curves where primary controllers continuously monitor local voltage and frequency parameters. When deviations occur, the controllers adjust power flow automatically based on the droop characteristics, maintaining voltage stability without requiring large capacitor banks for passive stabilization.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The droop control strategy changes the operational parameters of power converters dynamically. By adjusting the droop coefficients and set points based on system conditions, the controllers optimize power distribution to maintain voltage stability while minimizing the need for large energy storage capacitors.

Inventive Principle:

Principle #35Parameter changes

3Loss of information

If extensive communication infrastructure is implemented, then centralized control capability is improved, but system complexity and cost increase

Engineering Contradiction:

Improveinformation transmissionVSAvoidcommunication complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent extracts the control intelligence from a centralized location and distributes it to autonomous primary controllers at each energy resource. This eliminates the need for extensive communication infrastructure by removing the centralized control node, while maintaining effective coordination through distributed droop control mechanisms that rely on local parameter sensing.

Inventive Principle:

Principle #2Taking out (Extraction)

4Productivity

If droop power curves are implemented at primary controllers, then power management efficiency is improved, but control flexibility may be reduced

Engineering Contradiction:

Improvepower management efficiencyVSAvoidcontrol flexibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The droop power curve implementation is dynamic rather than static. Primary controllers can adjust droop coefficients and set points based on operating conditions, allowing the system to optimize power management efficiency under normal conditions while retaining flexibility to adapt to different operating modes and disturbance scenarios through parameter modification.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11520361B2Control for a target common bus voltage

Publication Date: 2022.12.06 ROLLS ROYCE SINGAPORE PTE LTD

AI summary

In some examples, a system includes a bus and a first power converter connected to the bus. The system also includes a second power converter connected to the bus, the second power converter having a topology different from the topology of the first power converter. The system further includes a power source and an energy storage device connected to the bus via the first and second power converters, respectively. In addition, the system includes a source controller configured to control the first power converter and a storage controller configured to control the second power converter. The system also includes a system controller configured to determine a first set point for the first power converter, transmit an indication of the first set point to the source controller, determine a second set point for the second power converter, and transmit an indication of the second set point to the storage controller.