Active power classified distribution method for hybrid energy storage system applied to micro-grid

Abstract

The invention discloses an active power classified distribution method for a hybrid energy storage system applied to a micro-grid. The active power classified distribution method is characterized in that the micro-grid hybrid energy storage system formed by a super-capacitor energy storage module, a storage battery energy storage module and an energy storage coordinating controller is arranged. The distributed method includes the following steps that 1, total active power of a hybrid energy storage target, a super capacitive SOC measured value and a storage battery SOC measured value are obtained; 2, first-level distribution is performed on the total active power of the hybrid energy storage target; 3, second-level distribution is performed based on the super-capacitor SOC measured value; 4, the second-level distribution is performed based on the storage battery SOC measured value; 5, distribution results are output to complete the active power classification and distribution. The active power classification and distribution method can effectively avoid over charging and over discharging of a super-capacitor and a storage battery, the number of times for circulation of the storage battery is reduced, service life of the super-capacitor and the storage battery is prolonged, and stability and performance indexes of the micro-grid are improved.

Description

technical field [0001] The invention relates to the field of application of energy storage technology in micro-grids, in particular to a method for grading and distributing active power applied to hybrid energy storage systems in micro-grids. Background technique [0002] A typical microgrid consists of a variety of distributed generation units, energy storage and loads, and the microgrid energy management system is responsible for power generation scheduling in the microgrid. Among them, energy storage plays a very important role in the stable control of microgrid, the improvement of power quality and uninterrupted power supply, and is the key factor to maintain the stable operation of microgrid. A single energy storage system only has one of the characteristics of large capacity or fast response, which cannot meet the needs of high-performance microgrids. Hybrid energy storage with both large capacity and fast response characteristics is of great importance to improve the ...

AI Technical Summary

Problems solved by technology

[0004] The first is to adopt a multi-hysteresis control strategy to distribute the output power of the supercapacitor and battery according to the output characteristics of the two, optimize the output of the battery, and improve the performance index of the microgrid. However, this control method does not consider the supercapacitor and battery. In the state of overcharge or overdischarge, the power output is limited, and the state of overcharge or overdischarge will cause damage to the supercapacitor and battery, reducing the service life of the supercapacitor and battery;

[0005] The second is the control strategy based on the energy storage SOC. This method is to maximize the total power of the hybrid energy storage under the SOC limit of the super capacitor, and cut off the charging or discharging of the super capacitor if the limit is not met. Function, the remaining power is output by the battery. This method effectively avoids the overcharge or overdischarge state of the supercapacitor, and at the same time minimizes the requirements for charging and discharging the battery and improves the service life of the supercapacitor. However, this method does not consider the battery The limit of overcharge or overdischarge may cause damage to the battery. At the same time, this control method has nothing to do with the output characteristics of the supercapacitor and the battery. Therefore, the supercapacitor is easy to enter the cut-off state and the performance index of the microgrid will decline. And this method When the energy storage SOC does not meet the requirements, a buffer zone is not set before entering the cut-off power output, which reduces the stability of the microgrid

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