DC Intermediate Circuit for One-Way Public-to-Local Grid Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional local power grids lack the necessary technical measures to prevent electricity generated or stored from being fed back into public power grids, limiting their functionality and flexibility, especially when integrated with electricity generator or storage systems.
Innovation Solution
A network coupling device with a direct current intermediate circuit is used to ensure electricity flows only from the public grid to the local grid, employing AC-DC converters, inverters, connection meters, fuses, renewable power generators, and power storage systems operated with direct current to prevent backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional local power grids are connected directly to public power grids, then electricity can be supplied from the public grid to the local grid, but electricity generated or stored in the local grid cannot be prevented from flowing back into the public grid
Solution Approach 1:
A direct current intermediate circuit is introduced between the public power grid and the local power grid. This intermediate circuit acts as a mediator that allows electricity to flow from the public grid to the local grid while preventing backflow to the public grid, thereby solving the reliability issue without requiring complex control systems.
Solution Approach 2:
The patent changes the electrical parameter domain by converting alternating current (AC) to direct current (DC) in the intermediate circuit. This parameter transformation enables unidirectional power flow control, as the DC intermediate circuit naturally prevents reverse flow back to the AC public grid, simplifying the technical measures needed for backflow prevention.
2Adaptability or versatility
If local power grids are equipped with power generation systems or storage systems, then functionality is enhanced, but ensuring electricity cannot flow back into the public grid becomes difficult
Solution Approach 1:
The direct current intermediate circuit serves as a one-way valve that enables the local grid to integrate photovoltaic systems and battery storage while preventing any electricity from flowing back to the public grid. The intermediate circuit decouples the local generation/storage systems from the public grid, allowing versatility without compromising reliability.
3Reliability
If a direct current intermediate circuit is introduced, then electricity backflow is prevented, but device complexity increases
Solution Approach 1:
By transforming the power flow from alternating current to direct current in the intermediate circuit, the patent achieves reliable backflow prevention through a relatively simple structural addition. The DC intermediate circuit requires minimal components compared to complex AC control systems, as the unidirectional nature of DC naturally prevents reverse flow.
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 solution enhances the flexibility and versatility of local power grids by ensuring one-way electricity flow from the public grid, allowing for the integration of renewable systems and storage without violating public grid conditions, thus expanding their operational capabilities.
Implementation Method 1
the grid coupling device is designed with a direct current intermediate circuit
Implementation Method 2
the DC-AC converter is preferably designed with a commercially available inverter
Data Source
Figure 1
AI summary
A network coupling device for coupling an alternating current-operated public power grid with a local power grid also operated with alternating current is, according to the invention, designed with a direct current intermediate circuit.