DC Contactor Starting in Energy Storage Systems
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Solution Overview
Problem
The existing energy storage systems face malfunctions due to the high current requirements of DC contactors, which can lead to instability and increased costs with the use of high-capacity power supplies.
Innovation Solution
An energy storage system that includes a battery system, a DC contactor, a power supply, and a rack BMS, where the DC contactor is started using both power from the power supply and the battery rack, with a converter to adjust voltage levels, and a switch controlled by the rack BMS to manage power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-capacity power supply is used to provide high current to the DC contactor, then the starting reliability is improved, but the system cost and complexity increase
Solution Approach 1:
The patent combines the power supply function with the battery system already present in the energy storage system. The DC contactor is configured to receive power from both the external power supply and the battery system simultaneously, merging two power sources to provide the high current needed for reliable starting without requiring a separate high-capacity power supply.
Solution Approach 2:
The battery system in the energy storage system serves dual purposes: it functions as both the energy storage component for the overall system and as a power source to assist in starting the DC contactor. This multi-functionality eliminates the need for dedicated high-capacity starting power supplies, reducing system complexity while maintaining starting reliability.
2Reliability
If high current is supplied to the DC contactor for starting, then the contactor can be reliably activated, but malfunctions such as communication cutoff occur
Solution Approach 1:
The control method activates the first contactor before the second contactor during the starting sequence. By preliminarily establishing the first power path, the system ensures controlled power distribution before full high-current operation begins, preventing communication cutoff while ensuring reliable contactor activation.
Solution Approach 2:
The system dynamically controls the activation sequence of multiple contactors and the distribution of power from different sources. The controller adjusts the timing and magnitude of current supply to each contactor based on system state, ensuring that high current is supplied only when and where needed, thereby avoiding communication interference while achieving reliable activation.
3Device complexity
If a small-capacity power supply is used, then system cost is reduced, but the DC contactor cannot be reliably started
Solution Approach 1:
The patent merges the power supply function with the battery system already present in the energy storage system. The DC contactor is configured to receive power from both the external power supply and the battery system simultaneously, merging two power sources to provide the high current needed for reliable starting without requiring a separate high-capacity power supply.
Solution Approach 2:
The battery system serves itself by providing power not only for energy storage functions but also for assisting in the starting of the DC contactor. This self-service capability allows the system to use its own stored energy to support critical starting operations, eliminating the need for external high-capacity power supplies.
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 approach allows for stable starting of the energy storage system while reducing costs by using a small-capacity power supply and preventing malfunctions such as communication cutoff, thereby ensuring efficient energy storage and conversion.
Implementation Method 1
a converter connected between the DC contactor and the battery system, to convert the level of power stored in the battery rack into a voltage level required by the DC contactor
Data Source
AI summary
An energy storage system and a starting method thereof are disclosed. In one aspect, the energy storage system includes a battery system, a direct current (DC) contactor and a power supply. The battery system includes at least one battery rack, wherein the battery rack is configured to provide first power. The DC contactor electrically connects a current path between the battery system and a power conversion system. The power supply is electrically connected to the DC contactor. In the energy storage system, the DC contactor is configured to be turned on based on at least the first power.