Offline wireless parallel operation method of a plurality of energy storing converters in large-capacity energy storing system

Abstract

The invention discloses an offline wireless parallel operation method of a plurality of energy-storing converters in a large-capacity energy storing system. The method is that the energy storing converters are free of interconnection wires, so that each energy storing converter independently acquires three-phase voltage and three-phase current at each AC side to be independently controlled; when the large-capacity energy storing system is operated offline, each energy storing converter is subjected to droop control; each energy storing converter is selectively converted into an offline working mode or quitted from the offline working mode according to the photoelectric generating, wind-powered generating and load conditions; the corresponding working mode of each energy storing converter is converted according to the working state of each energy storing element. With the adoption of the method, energy storing converters can be plugged and played, the problem that the capacity of the large-capacity energy storing system is difficultly expanded during independent operating is solved, and therefore, the usability and stability of the system are improved; the system operation mode is flexible; the energy storing elements can be maintained and overhauled conveniently, and as a result, the service lives of the energy storing elements can be prolonged.

Description

technical field [0001] The invention belongs to the field of power systems, and more specifically relates to a micro-grid control technology including distributed power sources and multi-energy storage converters, which is suitable for off-grid parallel operation control technology of multi-energy storage converters in large-capacity energy storage systems. Background technique [0002] Solar power and wind power technologies are developing rapidly, and their capacity is increasing; however, solar power and wind power are inherently intermittent, unstable and uncontrollable. If they are directly connected to the grid, it will affect the stable operation of the grid. The energy system can stabilize the fluctuation of this intermittent energy, reduce its impact on the grid, and make its characteristics tend to be controllable "grid-friendly". Thanks to the addition of the energy storage system, solar power and wind power can operate independently with the energy storage system...

AI Technical Summary

Problems solved by technology

The advantage of the centralized control method is that the control is simple, and there is no circulation among multiple PCSs; the disadvantage is that the reliability of the centralized controller is high. Once the centralized controller fails, the entire system cannot operate, and the system has a single operating mode and is difficult to expand.

The master-slave control method cancels the centralized controller, avoiding the situation that the system cannot run due to the problem of the centralized controller; but the master-slave control method needs to select a PCS as the host, resulting in the low capacity of the main power supply in the system and the ability to resist load fluctuations Worse; although the host can be switched, the switching process requires a power outage

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