Modular Multilevel Converter Architecture for Centralized Battery Storage
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Solution Overview
Problem
Battery energy storage systems with numerous low voltage energy provisioning devices require a large number of transformers and inverters, leading to increased management complexity, cost, and harmonic distortion, especially when distributing power across long distances or to large loads.
Innovation Solution
Implementing modular multilevel converters (MMCs) that centralize power conversion, reducing the number of transformers needed and enhancing control, while converting direct current to alternating current with improved power availability and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple step-up transformers are used to convert low voltage DC power from distributed batteries into high voltage power, then the voltage is stepped up and amperage requirements are met, but the number of computer systems required to manage, control, and synchronize the transformers increases proportionally, increasing system complexity and cost
Solution Approach 1:
Multiple step-up transformers and their associated computer control systems are merged into a single modular multilevel converter (MMC). The MMC integrates the voltage conversion function and centralized control into one device, eliminating the need for multiple separate transformers and computer systems while achieving the same high voltage output from distributed battery sources.
Solution Approach 2:
The modular multilevel converter performs multiple functions simultaneously: it converts low voltage DC to high voltage DC, provides centralized control, synchronizes power from multiple battery sources, and manages power flow. This multi-functional device replaces what previously required separate specialized components for each function.
2Power
If multiple step-up transformers are deployed across the system to handle power from distributed batteries, then power conversion is achieved, but the costs to provision all of the step-up transformers increase proportionally to the number of batteries
Solution Approach 1:
The patent combines multiple transformer functions into a single modular multilevel converter. Instead of deploying one transformer per battery or small group of batteries, the MMC handles power from all distributed batteries through one integrated device, dramatically reducing the total number of transformers required in the system.
Solution Approach 2:
The modular multilevel converter is itself constructed from modular units that can be scaled to handle different power levels. This segmentation allows the system to accommodate varying numbers of batteries without requiring proportional increases in transformer quantity, as the MMC can be configured to match the specific power conversion needs.
3Productivity
If distributed battery systems use multiple independent step-up transformers, then each transformer can handle local power conversion, but the total harmonic distortion to and from the electrical grid increases
Solution Approach 1:
By merging multiple independent transformer operations into a single coordinated modular multilevel converter, the system achieves synchronized power conversion. This centralized coordination allows for better control of switching operations and current waveforms, reducing harmonic distortion compared to multiple independent transformers operating in parallel.
Solution Approach 2:
The modular multilevel converter incorporates centralized control with feedback mechanisms that monitor and adjust power conversion in real-time. This feedback control optimizes the switching patterns and current management, minimizing harmonic generation and improving power quality delivered to the electrical grid.
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
MMC technology reduces transformer count, lowers operational costs, and minimizes harmonic distortion, providing centralized control and increased redundancy in battery energy storage systems.
Implementation Method 1
a main modular multilevel converter (MMC) configured to accept the second direct current and to provide an alternating current at a third voltage
Data Source
AI summary
A battery energy storage system includes a plurality of battery cores. Each battery core of the battery energy storage system includes an array of battery cubes, and each battery core is configured to provide a first direct current power at a first voltage. The battery energy storage system further includes a plurality of direct-current-to-direct-current (DC-DC) converters. Each DC-DC converter of the battery energy storage system is configured to accept the first direct current power and each DC-DC converter is configured to provide a second direct current power at a second voltage. The battery energy storage system further includes a main modular multilevel converter (MMC). The MMC of the battery energy storage system is configured to accept the second direct current and to provide an alternating current at a third voltage.