Multi-Port Energy Router Stability Recovery via Impedance Reshaping

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Solution Overview

Problem

Current energy router systems face challenges in stability identification and recovery, particularly due to the complex interactions between their sub-systems, leading to instability issues that are difficult to address using existing impedance-based stability analysis methods.

Innovation Solution

A self-mutual-group multilevel stability identification and stability recovery method is introduced, which involves system parameter initialization, construction of Euler-Lagrange mathematical models, and use of transfer functions to assess stability, followed by a three-layer impedance reshaping strategy to ensure system stability across different hierarchies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional impedance-based stability analysis methods are used, then stability evaluation can be performed, but conservatism in stability evaluation occurs and coupling stability problems cannot be effectively solved

Engineering Contradiction:
Improvestability evaluation accuracyVSAvoidsystem stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the energy router system into three hierarchical levels: self-hierarchy (individual converter modules), mutual-hierarchy (converter groups with coupling), and group-hierarchy (overall system). Each level has dedicated stability identification methods, allowing precise analysis without conservatism while managing complex coupling relationships through structured decomposition.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If complex stability identification methods are implemented to solve coupling stability problems, then stability accuracy improves, but system complexity and computational burden increase

Engineering Contradiction:
Improvestability identification accuracyVSAvoidanalysis method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a hierarchical dimension to stability analysis, organizing the complex multi-port energy router system into three distinct levels (self-, mutual-, and group-hierarchy). This dimensional organization transforms an intractable complex problem into a series of manageable sub-problems, each with appropriate analysis methods, reducing overall computational burden while maintaining accuracy.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs dynamic impedance characterization that adapts to different operating conditions and hierarchy levels. The stability identification methods dynamically adjust their complexity based on the specific hierarchy being analyzed, using simplified models where appropriate and more sophisticated analysis only where needed, optimizing the balance between accuracy and computational effort.

Inventive Principle:
Principle #15Dynamics

3Reliability

If multi-level stability recovery control is implemented, then system stability is ensured, but control complexity and implementation difficulty increase

Engineering Contradiction:
Improvesystem stabilityVSAvoidcontrol implementation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The stability recovery control is segmented into three hierarchical levels corresponding to the stability identification framework. Each level has dedicated control strategies that address specific types of instability, allowing implementation of comprehensive stability recovery without requiring a single overly complex control system. This modular approach simplifies implementation while ensuring overall system stability.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3817177B1Self-mutual-group multi-level stability identification and stability recovery method for multi-port energy router
Publication Date: 2024.03.13 NORTHEASTERN UNIV CHINA
  • EP3817177B1 patent drawingFigure 1
  • EP3817177B1 patent drawingFigure 2
  • EP3817177B1 patent drawingFigure 3~4

AI summary

The present invention provides a self-mutual-group multilevel stability identification and stability recovery method for a multi-port energy router, and relates to the technical field of Energy Internet. The method comprises a stability identification method for a dual energy flow multi-port energy router based on an impedance criterion, and an impedance reshaping stability recovery control strategy. The method comprises steps of firstly, identifying respective stability of three sub-systems of a front-end DC converter, a dual active bridge bidirectional DC-DC converter and a back-end AC/DC converter in energy routers; then obtaining the single stability of a single dual energy flow multi-port mutual-coupling energy router through an MFC fractional criterion, and further obtaining the stability of a clustered energy router through an impedance flow diagram; and finally proposing a three-layer impedance reshaping stability recovery control strategy for three instability phenomena, and enabling the system to be stable through a parameter self-regulation technology, a passive coupling impedance reshaping technology and a source side cascade impedance reshaping technology. The method can guarantee the whole stability of the Energy Internet system and realize expandability, plug-and-play properties and safe and stable operation of the system.