Improved equalization control method for multiple energy storage units of direct-current microgrid

Abstract

The invention relates to the field of electrical control, in particular to an improved equalization control method for multiple energy storage units of a direct-current microgrid. The improved equalization control method comprises the following steps of: constructing an equalization control circuit of the multiple energy storage units of the direct-current microgrid, constructing a monotonically increasing function according to self charge state parameters, and introducing the monotonically increasing function into an energy storage unit improved droop control loop, so as to form a reference voltage of the control system; and enabling the reference voltage, the sampled output voltage and the sampled input current to form a double-closed-loop control system, outputting a duty ratio controlsignal by a digital controller to drive a switching power device, and realizing communication-free self-adaptive droop control of an energy storage unit. According to the improved equalization controlmethod, an algorithm is applied to two working modes of charging and discharging of the energy storage unit, switching is not needed, output current of the interface converter does not need to be sampled, and the design of the controller is simplified.

Description

technical field [0001] The invention relates to the field of electrical control, in particular to an improved balance control method for multiple energy storage units of a DC microgrid. Background technique [0002] In recent years, as a power supply system that integrates distributed energy, energy storage components, and power converters, microgrids have attracted extensive attention from academic circles in various countries. As a reliable and efficient power supply method, DC microgrid has become an important form of future intelligent power distribution system due to its advantages of strong system reliability, high transmission efficiency and no need to consider phase, reactive power and harmonic issues. [0003] As a small inertia and weak support system, the DC microgrid usually has a small capacity and does not have good anti-interference ability. In order to meet the stable operation of the system and increase the capacity configuration, the energy storage units (...

AI Technical Summary

Problems solved by technology

[0005] However, the control method proposed in the above literature ignores the line resistance between the converter output terminal and the DC bus, and the droop control expressions corresponding to the charging and discharging process are different. During the dynamic conversion process of the energy storage unit, the controller Frequent switching is required, which not only increases the difficulty of controller design, but also adversely affects the control effect of the system

Images