DC Energy Store Circuit for Auxiliary Power Continuity
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Solution Overview
Problem
DC energy stores face operational challenges when the ac supply network experiences interruptions or voltage/frequency transients, leading to power disruptions for auxiliary systems like pumps and fans, which can result in temperature increases and efficiency issues.
Innovation Solution
A DC energy store circuit with AC/DC and DC/DC power converters, controlled by independent controllers, allowing the system to operate in self-supporting, island, and normal modes, ensuring continuous power supply to auxiliary systems by isolating from the ac supply network and using stored energy when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary systems are connected to the ac supply network, then they receive power under normal conditions, but they experience power disruptions when the ac supply network fails or experiences transients
Solution Approach 1:
The patent introduces a DC energy store as an intermediary component between the AC supply network and auxiliary systems. The DC energy store acts as a buffer that can supply power independently when the AC network fails, while also serving as a bridge during normal operation. This mediator resolves the contradiction by providing power reliability without requiring direct complex coupling between AC network and auxiliary systems.
Solution Approach 2:
The patent implements dynamic switching capability that allows the system to transition between different operating modes (AC-supplied mode, self-supporting mode, island mode). The controllers dynamically adjust the operation of power converters based on real-time conditions, enabling the auxiliary systems to receive power from either the AC network or the DC energy store. This dynamic adaptability resolves the contradiction by providing reliability through mode switching rather than permanent complex infrastructure.
2Reliability
If the system operates in self-supporting mode isolated from the ac supply network, then auxiliary systems receive continuous power, but the system cannot utilize the ac supply network for energy management
Solution Approach 1:
The patent employs dynamic control strategies that enable seamless transitions between self-supporting mode and AC-connected modes (normal and island modes). The controllers monitor system conditions and automatically adjust the operating mode to optimize both reliability and adaptability. This resolves the contradiction by making the isolation state dynamic rather than fixed, allowing the system to switch between connected and isolated operations as needed.
Solution Approach 2:
The DC energy store and power converters are designed to perform multiple functions across different operating modes. In self-supporting mode, they provide power to auxiliary systems; in normal mode, they enable energy storage and grid interaction; in island mode, they support AC loads. This multi-functionality resolves the contradiction by ensuring that the components designed for self-supporting operation also contribute to overall system versatility and adaptability.
3Reliability
If power converters with multiple controllers are used to manage different operating modes, then the system achieves reliable power supply, but the control system complexity increases
Solution Approach 1:
The patent divides the control function into separate controllers for different power converters (AC/DC converter controller and DC/DC converter controller). Each controller manages specific aspects of power conversion and can operate independently in different modes. This segmentation resolves the contradiction by distributing control complexity across multiple specialized units rather than requiring a single complex centralized controller, thereby maintaining reliability through distributed control while managing overall system complexity.
4Duration of action of moving object
If the dc energy store supplies power to auxiliary systems during ac supply failures, then operational continuity is maintained, but energy is consumed from the stored energy reducing availability for main functions
Solution Approach 1:
The patent enables continuous operation of auxiliary systems by maintaining power supply from the DC energy store during AC failures. The system is designed to sustain auxiliary loads for extended periods, with the energy store sized to provide adequate backup duration. This resolves the contradiction by ensuring operational continuity is maintained through proper energy storage capacity planning, allowing the system to bridge AC failures without interrupting auxiliary operations.
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
Enables reliable operation of auxiliary systems during ac supply network failures, maintains optimal shutdown conditions, and efficiently manages power storage and discharge, ensuring continuous operation and efficient energy management.
Implementation Method 1
an AC/DC power converter including a plurality of semiconductor power switching devices, the AC/DC power converter having dc terminals and ac terminals that are electrically connected to an ac supply network
Implementation Method 2
a DC/DC power converter including a plurality of semiconductor power switching devices, the DC/DC power converter having first dc terminals electrically connected to the dc terminals of the AC/DC power converter by means of a dc link and second dc terminals electrically connected to dc terminals of the dc energy store
Implementation Method 3
AC/DC power converter including a plurality of semiconductor power switching devices, the DC/DC power converter including a plurality of semiconductor power switching devices
Data Source
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AI summary
A dc energy store (2) that includes auxiliary systems (68) can be operated in one or more different modes, including a self-supporting mode, an island mode and a normal mode. In the self-supporting mode a first controller (24) uses a voltage demand signal (VACr) indicative of desired ac voltage at the ac terminals of an AC/DC power converter (4) to control semiconductor power switching devices of the AC/DC power converter (4) to achieve the desired level of ac voltage that corresponds to the voltage demand signal (VACr). The voltage demand signal (VACr) is derived from a comparison of a voltage feedback signal (VACfb) and a second voltage demand signal (VACsr) that is preset to provide the desired ac voltage for the auxiliary systems (68) of the dc energy store. A second controller (46) uses a current demand signal (Ior) indicative of the desired dc link current to control the semiconductor power switching devices of a DC/DC power converter (14) to achieve the desired level of dc link current that corresponds to the current demand signal (Ior). The current demand signal (Ior) is derived from a comparison of a dc link voltage demand signal (VDCr) indicative of a desired dc link voltage and a dc link voltage feedback signal (VDCbus).