SOC balancing and power sharing control method of direct-current micro-grid energy storage system

Abstract

The invention provides an SOC balancing and power sharing control method of a direct-current micro-grid energy storage system. The method comprises the following steps: 1, acquiring state-of-charge values of a first battery and a second battery in real time through low-bandwidth communication; 2, calculating the average value of the charge state values of the first battery and the second battery; and 3, obtaining a difference value between the charge state value of the first battery or the charge state value of the second battery and the average value, inputting the difference value into a first PI controller, and outputting a regulating variable by the first PI controller. According to the method, bus voltage drop caused by a droop coefficient is effectively avoided, low-bandwidth communication is adopted, the average value of the SOC of different energy storage units is calculated, the SOC average value PI closed-loop control is adopted, the regulating variable acts on the output voltage reference value of the converter, SOC balance of the energy storage units is achieved, and power equalization is achieved under the condition that the capacities of the energy storage units are the same.

Description

technical field [0001] The invention relates to the technical field of DC microgrid operation and control, in particular to an SOC balance and power sharing control method for a DC microgrid energy storage system. Background technique [0002] With the aggravation of energy and environmental problems worldwide, microgrids have attracted extensive attention from scholars from all over the world. DC microgrid does not need to consider the problems existing in AC microgrid such as reactive power and harmonic current, so the research on DC microgrid is gradually increasing. The increasing number of DC equipment such as electric vehicles and computers is the trend of future smart grid development. Distributed energy generation is affected by geographical and other factors, resulting in randomness, intermittency and volatility in new energy generation. Direct access to the microgrid system will challenge the stability of the power grid. The energy storage unit adopts an effectiv...

AI Technical Summary

Problems solved by technology

[0004] The invention provides an SOC balance and power sharing control method for a DC microgrid energy storage system, the purpose of which is to solve the problem that the traditional SOC balance control strategy uses droop control combined with low-bandwidth communication, causing the bus voltage drop to be too large

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