Multi-Converter Energy Storage System for DC Network Voltage Control
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Solution Overview
Problem
Conventional energy storage systems face inefficiencies in battery charging and discharging, leading to overloads and unreliable power supply when converters fail, which affects the overall reliability and efficiency of the energy storage system.
Innovation Solution
The proposed energy storage system employs multiple converters to manage power flow between the power system, DC power distribution network, and load, including a first converter for voltage control, a second converter for load voltage control, a third converter for battery discharge control, and a fourth converter for battery charging and discharging, with an auxiliary power system and switch to ensure uninterrupted power supply even when converters fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single DC to DC converter is used between the battery and the load, then the system structure is simple, but the converter experiences overload during discharge operations and the system reliability is low
Solution Approach 1:
The patent divides the single converter function into multiple converters with different functions: a first converter for voltage control of the DC power distribution network, a second converter for load voltage control, a third converter for battery discharge control, and a fourth converter for battery charging/discharging control. This segmentation distributes the power flow paths, preventing any single converter from experiencing overload while maintaining system reliability.
2Device complexity
If a single converter is used for battery discharge control, then the device complexity is low, but the converter cannot handle overload conditions and power supply fails when the converter fails
Solution Approach 1:
The patent implements multi-functionality by enabling the battery to supply power to the load through multiple converters with different control functions. The third converter specifically controls battery discharge to the load, while the fourth converter manages battery charging and discharging to the power system. This multi-functional converter configuration allows the system to handle overload conditions by distributing power flow and ensures continuous operation even if one converter fails.
3Manufacturing precision
If a separate converter is used between the DC power distribution network and the battery, then the voltage control is precise, but the device complexity and cost increase
Solution Approach 1:
The patent merges the voltage control function into the existing converter structure. The first converter controls the voltage of the DC power distribution network to which the battery is connected, and the third converter controls the discharge of the battery to the load. By integrating voltage control into these existing converters rather than adding a separate dedicated converter, the system maintains precise voltage control while avoiding unnecessary increase in device complexity and cost.
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 configuration reduces overload on converters during discharge, ensures reliable power supply by providing multiple paths for power transfer, and improves conversion efficiency by eliminating the need for a separate converter between the DC power distribution network and the battery, thereby enhancing the system's reliability and cost-effectiveness.
Implementation Method 1
a first converter connected to and disposed between the power system and the DC power distribution network and configured to control voltage of the DC power distribution network
Implementation Method 2
a second converter connected to the DC power distribution network; a load connected to the second converter, wherein the second converter is configured to control voltage of the load
Implementation Method 3
a third converter connected to and disposed between the battery and the load, and configured to control discharging of the battery
Implementation Method 4
a fourth converter connected to and disposed between the battery and the power system, wherein the fourth converter is configured to control charging and discharging of the battery
Data Source
AI summary
The present invention relates to an energy storage system. An energy storage system, according to an embodiment of the present invention, relates to an energy storage system for managing power of a system and a direct current (DC) distribution network linked with the system, the energy storage system comprising: a first converter connected between the system and the DC distribution network so as to control a voltage of the DC distribution network; a second converter connected to the DC distribution network; a load connected to the second converter, and controlling the voltage by means of the second converter; a battery connected to the DC distribution network; and a third converter connected between the battery and the load, and controlling discharge of the battery.