Energy Storage Grid Connection Pre-Charging for Impulse Suppression
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Solution Overview
Problem
Energy storage apparatuses face significant damage due to excessively large instantaneous impulse currents and voltages generated during grid connection, which shortens their service life, compromises safety, and can damage connected power grids and devices.
Innovation Solution
A grid connection control method for energy storage apparatuses, where energy storage units pre-charge voltage-sharing capacitors before connecting the main energy transmission circuit to the direct-current bus, thereby reducing impulse currents and voltages, and implementing a charging treatment based on SOC information and a control policy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the energy storage apparatus is connected to the direct-current bus for grid connection, then the energy storage apparatus can be charged by the electric power system, but excessively large instantaneous impulse current and impulse voltage are generated causing damage to the energy storage apparatus and power grid
Solution Approach 1:
The patent applies preliminary action by pre-charging the voltage-sharing capacitors through the energy storage units before the main energy transmission circuit is connected to the direct-current bus. This preliminary charging action ensures that the capacitors are ready to share voltage when connection occurs, thereby preventing excessive impulse current and voltage during grid connection while maintaining reliable charging operation
2Use of energy by moving object
If the main energy transmission circuit is connected to the direct-current bus, then the energy storage apparatus can receive electrical energy for charging, but the instantaneous impulse current and voltage cause significant damage and shorten service life
Solution Approach 1:
The patent implements preliminary action by sequentially controlling the energy storage units to pre-charge the voltage-sharing capacitors before connecting the main energy transmission circuit to the direct-current bus. This preliminary charging ensures that when the connection is made and charging begins, the impulse current and voltage are controlled, thereby protecting the energy storage apparatus and extending its service life while maintaining full charging capability
Solution Approach 2:
The voltage-sharing capacitors serve as intermediaries between the energy storage units and the direct-current bus. These capacitors temporarily store and redistribute energy during the connection process, acting as a buffer that mediates the energy transfer and prevents harmful impulse effects while allowing normal charging operation to proceed
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
The method enhances the reliability and safety of grid connections by reducing damage to the energy storage apparatus and connected power grids, prolonging the service life of the energy storage apparatus, and ensuring a stable charge process.
Implementation Method 1
The energy storage unit pre-charges the corresponding voltage-sharing capacitor
Data Source
AI summary
A grid connection control method of an energy storage apparatus, an energy storage control unit, an energy storage system, and a storage medium are provided and relate to the field of energy storage technologies, where the method includes: sequentially controlling energy storage units of energy storage sub-modules to be connected to corresponding voltage-sharing capacitors in a state in which a main energy transmission circuit is disconnected from a direct-current bus, so as to make the energy storage units pre-charge the corresponding voltage-sharing capacitors; and controlling the main energy transmission circuit to be connected to the direct-current bus under a condition that the voltage-sharing capacitor of each energy storage sub-module meets a voltage-sharing capacitor pre-charge completion condition.