Research on DC Microgrid Operation Based on Improved Droop Control

doi:10.12096/j.2096-4528.pgt.21003

Abstract

Abstract:

Taking photovoltaic array power generation, lithium battery energy storage, DC load and grid-side converter as the research objects, the whole system was divided into 6 working modes, and the coordinated control strategy of the microgrid was studied through the conversion operation of different working modes. The lithium battery was divided into two groups. In order to improve the efficiency of the battery and the whole system and optimize the working characteristics of the battery, the idea of energy balance was introduced, and the energy balance algorithm was combined with the droop control based on the state of charge value, which helped to achieve power balance of two groups of lithium batteries. The simulation model of the system was built using Matlab/Simulink software. The change of system operation was realized by changing the size of load power. The simulation results show that the DC bus voltage keeps constant, the power balance of the entire system is realized, and the feasibility of the coordinated control strategy of the system is verified.

Key words: DC microgrid, coordinated control, energy balance, droop control

CLC Number:

TK01
TM76

Jing LI, Zhihe WANG, Hao NI. Research on DC Microgrid Operation Based on Improved Droop Control[J]. Power Generation Technology, 2021, 42(6): 765-774.

Figures/Tables 12

Fig.1 Diagram of DC microgrid structure

Fig.2 Diagram of DC bus equivalent circuit

Fig.3 Working principle diagram of operating mode

Fig.4 Control block diagram of photovoltaic Boost converter

Fig.5 Block diagram of SOC droop control based on energy balance

Fig.6 Block diagram of constant voltage charge and discharge control

Fig.7 Block diagram of AC/DC converter control strategy

Fig.8 Simulation curve of SOC droop control based on energy balance

Fig.9 Simulation diagram of operation mode 1 and operation mode 2

Fig.10 Simulation diagram of operation mode 2 and operation mode 3

Fig.11 Simulation diagram of operation mode 4 and operation mode 5

Fig.12 Simulation diagram of operation mode 5 and operation mode 6

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