Direct DC Coupled Energy Storage System Voltage Control
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Solution Overview
Problem
Existing energy storage systems face inefficiencies and high costs due to the need for multiple power converters, expertise, and space requirements, particularly when interfacing renewable energy sources like solar or wind with energy storage units in microgrid systems.
Innovation Solution
An energy storage system that employs direct DC coupling of an energy storage unit to a power source, utilizing a power converter and a control system to adjust voltage and manage electrical connections/disconnections, along with a break path to manage in-rush currents and power limits, allowing for efficient energy transfer without the need for intervening DC/DC converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple power converters are employed to interface renewable energy sources with energy storage units, then efficient power transmission is achieved, but system cost, complexity, and space requirements increase
Solution Approach 1:
The patent extracts and eliminates the DC/DC converter from the traditional power conversion system by implementing direct DC coupling between the renewable energy source and energy storage unit. This removes one complete power conversion stage, reducing system complexity, cost, and space while maintaining efficient power transmission through direct electrical connection.
Solution Approach 2:
The patent merges the power source and energy storage unit into a directly coupled system, combining their functions without intermediate conversion devices. This integration simplifies the overall system architecture while preserving the efficiency benefits of dedicated power conversion stages.
2Use of energy by moving object
If multiple power converters are used to convert power between renewable sources and energy storage units, then efficient energy conversion is achieved, but system cost increases
Solution Approach 1:
The patent extracts the DC/DC converter from the system, eliminating its associated cost while relying on the inherent efficiency of direct DC connections and the existing AC/DC or DC-AC converters to maintain overall energy conversion efficiency.
Solution Approach 2:
The patent makes the existing power converters serve dual functions by having them handle both the renewable energy source interfacing and energy storage unit interfacing through direct DC coupling, eliminating the need for separate dedicated converters for each interface.
3Ease of operation
If multiple power converters and control systems are implemented, then precise power control is achieved, but implementation time and expertise requirements increase
Solution Approach 1:
The patent removes the DC/DC converter and its associated control system, reducing the number of devices requiring installation, configuration, and commissioning. This decreases implementation time and the level of expertise required while maintaining power control precision through the simplified direct coupling architecture.
4Loss of energy
If traditional power conversion systems with multiple converters are used, then efficient power transmission is achieved, but space requirements increase
Solution Approach 1:
The patent extracts the DC/DC converter from the system, eliminating the physical space it would occupy along with its associated cooling, mounting, and clearance requirements. This reduces the overall system footprint while maintaining efficient power transmission through direct electrical connection.
Data Source
AI summary
An energy storage system for direct DC coupling includes a power source electrically connected to a first node, a power converter coupled to the first node, an energy storage unit coupled to the first node through direct DC coupling, and a control system. The power converter controls the output voltage of the power source under the control of the control system. The energy storage unit draws energy from the power source or the bus when charging and supplies energy to the bus when discharging. A main switch is coupled between the first node and the energy storage unit. The control system is configure to control the power converter to adjust the output voltage to the energy storage unit voltage, control the main switch to electrically connect the energy storage unit to the first node, and control the main switch to electrically disconnect the energy storage unit from the first node.