Non-constant Slope Droop Control for Power Systems

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Traditional droop control procedures in electric power systems with energy storage modules lead to instability due to fixed slope control, increasing complexity and cost when centralized control is employed to address variable capacity issues.

Innovation Solution

Implementing non-constant slope droop control lines, which can be piece-wise linear or have variable curvature, that adjust based on state of charge, health, energy, power, and temperature measurements of energy storage modules, allowing for autonomous operation and reducing reliance on centralized control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fixed-slope linear droop control is used, then the control procedure is simple, but system stability deteriorates when energy storage capacity changes

Engineering Contradiction:
Improvecontrol procedure complexityVSAvoidsystem stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic droop control by making the droop slope variable rather than fixed. The controller adjusts the droop slope in real-time based on the state of charge of the energy storage module, transitioning from a static fixed-slope approach to a dynamic adaptive approach that maintains stability across varying capacity conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the droop control parameter (slope) dynamically based on energy storage state. By modifying the droop slope parameter according to state of charge levels, the system adapts to changing capacity conditions without requiring complex centralized control architecture.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If centralized control scheme is employed to handle variable capacity, then system stability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvesystem stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables each energy storage module to autonomously adjust its own droop control parameters based on its state of charge. This self-service approach eliminates the need for complex centralized control, as each module independently adapts to its capacity conditions while maintaining overall system stability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent dynamically adjusts droop control parameters at the distributed level rather than through centralized coordination. By changing the droop slope parameter locally based on state of charge, the system achieves stability without the complexity of centralized control architecture.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If fixed-slope droop control is used, then control implementation is simple, but adaptability to varying energy storage capacity deteriorates

Engineering Contradiction:
Improvecontrol implementation simplicityVSAvoidadaptability to capacity changes
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent transitions from static fixed-slope control to dynamic droop control where the slope automatically adjusts with state of charge. This dynamic approach maintains ease of operation through automated adjustment while significantly improving adaptability to varying energy storage capacity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent modifies the droop slope parameter dynamically based on state of charge measurements. This parameter change approach maintains implementation simplicity through automated control logic while achieving high adaptability to different capacity conditions throughout the energy storage lifecycle.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3496225B1Method and system for droop control of power systems
Publication Date: 2022.05.18 GENERAL ELECTRIC CO
  • EP3496225B1 patent drawingFigure 1
  • EP3496225B1 patent drawingFigure 2
  • EP3496225B1 patent drawingFigure 3

AI summary

There is provided a system (100) that includes a processor. The system (100) also includes a memory (1104) that stores instructions; when executed by the processor (1102), the instructions configure the processor (1102) to perform certain operations. The operations include receiving sensor measurements from an electric power source or device (104) and generating, based on the sensor measurements, a droop control procedure (800) that includes a droop control curve (801, 802, 804, 806, 808) having a non-constant slope. The operations further include regulating a power delivery from the electric power source or device (104) to a bus (102) according to the droop control procedure (800).