Wei Chen, Nan Qiu^*, Xusheng Yang

Energy Engineering, Vol.121, No.4, pp. 987-1005, 2024, DOI:10.32604/ee.2023.045475

Abstract During the operation of a DC microgrid, the nonlinearity and low damping characteristics of the DC bus make it prone to oscillatory instability. In this paper, we first establish a discrete nonlinear system dynamic model of a DC microgrid, study the effects of the converter sag coefficient, input voltage, and load resistance on the microgrid stability, and reveal the oscillation mechanism of a DC microgrid caused by a single source. Then, a DC microgrid stability analysis method based on the combination of bifurcation and strobe is used to analyze how the aforementioned parameters influence the oscillation characteristics of the system.… More >

Feng Zhao, Jinshuo Zhang^*, Xiaoqiang Chen, Ying Wang

Energy Engineering, Vol.121, No.2, pp. 339-358, 2024, DOI:10.32604/ee.2023.043082

Abstract In the DC microgrid, the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power. To address this issue, the application of a virtual synchronous generator (VSG) in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator (AVSG) control strategy for the interface DC/DC converter of the battery in the microgrid. Besides, a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control. Firstly, a… More >

Jingjing Tian¹, Shenglin Mo^1,*, Feng Zhao¹, Xiaoqiang Chen²

Energy Engineering, Vol.121, No.2, pp. 439-459, 2024, DOI:10.32604/ee.2023.029956

Abstract In this paper, an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load and PV power variations in a stand-alone DC microgrid. The strategy includes primary and secondary control. Among them, the primary control suppresses the DC microgrid voltage fluctuation through the Ⅰ and Ⅱ section control, and the secondary control aims to correct the P-U curve of the energy storage system and the PV system, thus reducing the steady-state bus voltage excursion. The simulation results demonstrate that the… More >

Feng Zhao, Chengrui Xiao^*, Xiaoqiang Chen, Ying Wang

Energy Engineering, Vol.120, No.6, pp. 1353-1370, 2023, DOI:10.32604/ee.2023.025976

Abstract With the penetration of a large number of photovoltaic power generation units and power electronic converters, the DC microgrid shows low inertia characteristics, which might affect the stable operation of the microgrid in extreme cases. In order to enhance the “flexible features” of the interface converter connected to the DC bus, a control strategy of DC microgrid with photovoltaic and energy storage based on the virtual DC generator (VDCG) is proposed in this paper. The interface converters of the photovoltaic power generation system and the energy storage system simulates the inertia and damping characteristics of the DC generator to improve… More >

Wenqian Zhang¹, Jingwen Chen^1,*, Saleem Riaz³, Naiwen Zheng¹, Li Li²

CMES-Computer Modeling in Engineering & Sciences, Vol.132, No.2, pp. 585-604, 2022, DOI:10.32604/cmes.2022.020523

Abstract Distributed collaborative control strategies for microgrids often use periodic time to trigger communication, which is likely to enhance the burden of communication and increase the frequency of controller updates, leading to greater waste of communication resources. In response to this problem, a distributed cooperative control strategy triggered by an adaptive event is proposed. By introducing an adaptive event triggering mechanism in the distributed controller, the triggering parameters are dynamically adjusted so that the distributed controller can communicate only at a certain time, the communication pressure is reduced, and the DC bus voltage deviation is effectively reduced, at the same time,… More >