Modular Converter Battery Integration for AC Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing AC systems, especially those connected to unstable non-linear sources like wind farms, require energy storage systems for stability but current solutions involving separate AC/DC converters are complex and costly, and there is a need for a DC system that can effectively support AC systems without additional power electronics interfaces or galvanic isolation.
Innovation Solution
A cell-based voltage source converter system that integrates battery module groups within its cells, allowing for energy storage and support of AC systems without the need for a separate power electronics interface or galvanic isolation, with control mechanisms to selectively connect battery modules in parallel with cell capacitors for power exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery modules are connected to the AC grid via a separate AC/DC converter, then energy storage and AC system support are achieved, but device complexity and cost increase
Solution Approach 1:
The patent combines the battery energy storage system with the cell-based voltage source converter by integrating battery modules directly into the converter cells. This merging eliminates the need for separate AC/DC converters and galvanic isolation, reducing device complexity while maintaining AC system stability support functionality.
Solution Approach 2:
The voltage source converter is designed to perform multiple functions: it acts as both a power conversion device and an energy storage system. By integrating battery modules within the converter structure, the system provides both AC/DC conversion and energy storage capabilities, eliminating the need for separate dedicated energy storage converters.
2Reliability
If separate AC/DC converters are used for energy storage, then galvanic isolation is provided, but system cost and footprint increase
Solution Approach 1:
The patent merges the galvanic isolation function into the cell-based voltage source converter structure itself, eliminating the need for separate isolation converters. The converter cells provide inherent isolation capabilities while reducing overall system cost and footprint.
3Device complexity
If battery modules are directly integrated into converter cells, then device complexity is reduced, but selective connection and control become more challenging
Solution Approach 1:
The patent segments the battery energy storage system into multiple modular battery modules that can be independently controlled. Each converter cell can selectively connect to specific battery modules through switching elements, enabling flexible configuration and control while maintaining simple overall system structure.
Solution Approach 2:
The system employs dynamic switching mechanisms that allow converter cells to selectively connect to different battery modules based on operational requirements. This dynamic connection capability provides ease of operation for battery module selection while maintaining low device complexity through the modular architecture.
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 simplifies the energy storage system, reduces costs and complexity, and enables effective stabilization of AC systems by directly connecting battery modules at the cell voltage level, providing low-footprint, efficient power support for AC systems without the need for additional converters or isolation.
Implementation Method 1
each including a number of switching elements and a cell capacitor. The cells can here be controlled to provide a voltage contribution using the cell capacitors
Implementation Method 2
groups of battery modules within the cells, where the battery module groups can be selectively connected in parallel with corresponding cell capacitors for exchanging power with an associated AC system
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention concerns a method, voltage source converter and computer program product for supporting an associated AC system and comprising: a number of cells (CA1, CA2, CA3, CA4, CA5, CA6, CB1, CB2, CB3, CB4, CB5, CB6, CC1, CC2, CC3, CC4, CC5, CC6), each cell comprising a string of switching elements in parallel with a cell capacitor, at least some cells further including a battery module group comprising at least one battery module connectable in parallel with the cell capacitor and a control unit (20) configured to selectively connect the battery module groups of a number of cells in parallel with corresponding cell capacitors for exchanging power with the associated AC system.