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Virtual synchronous generator frequency response study of energy computing and storage devices

Zhang Baoge, Ping Shanyan, Long Yi, Jiao Yuemin, Wu Boxiang

Archives of Electrical Engineering

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2022

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Vol. 71, nr 4

895--907

EN

Renewable energy sources are connected to the grid through inverters, resulting in reduced grid inertia and poor stability. Traditional grid-connected inverters do not have the function of voltage and frequency regulation and can no longer adapt to the new development. The virtual synchronous generator (VSG) has the function of voltage and frequency regulation and has more outstanding advantages than the traditional inverter. Based on the principle of the VSG, the relationship between energy storage capacity, frequency response and output power of the VSG is derived, and the relationship between the virtual inertia coefficient, damping coefficient and frequency characteristics of the VSG and output power is revealed. The mathematical model is established and modeled using the Matlab/Simulink simulation software, and the simulation results verify the relationship between energy storage capacity and frequency response and the output power of the VSG.

2

Research on topology of a novel three-phase four-leg fault-tolerant NPC inverter

Zhang Baoge, Ping Shanyan, Long Yyi, Jiao Yyuemin, Wu Bboxiang

Archives of Electrical Engineering

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2022

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Vol. 71, nr 2

489--506

EN

Diode neutral point clamped (NPC) three-level converters have been widely used in recent years. Aiming at the problems of the high device failure rate and unstable neutral point potential of NPC three-level converters, an NPC three-level circuit with fourth bridge arm redundancy is proposed based on the traditional NPC three-level converter. The redundant fourth bridge arm is used to realize the function of stabilizing voltage when there is no fault and replacing the fault half-bridge arm to maintain the continuous operation of the converter when there is a fault. By analyzing the working principle of space vector pulse width modulation (SVPWM) and the power loss of the switch, it is of particular significance to the design and control of NPC three-level converters in the future. Matlab/Simulink verifies the feasibility of the fault-tolerant circuit structure.

3

A novel two-phase interleaved parallel bi-directional DC/DC converter

Zhang Baoge, Hong Deyu, Wang Tianpeng, Zhang Zhen, Wang Donghao

Archives of Electrical Engineering

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2021

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Vol. 70, nr 1

219--231

EN

The energy storage system (ESS) is an important way to improve the power quality of renewable energy sources (such as solar energy and wind energy). A bi-directional DC/DC converter is an essential part of the ESS to achieve bi-directional energy transfer. According to the characteristics of the low-voltage gain and high-voltage stress of switches in the existing bi-directional DC/DC converter, this study proposes a novel two-phase interleaved parallel bi-directional DC/DC converter. The converter can effectively combine the advantages of a Z-source network and interleaved parallel structure. The working principle, the boost mode and buck mode of the converter are analyzed in detail. In addition, the voltage conversion ratios under the two modes are deduced. The control strategy of the two-phase interleaved parallel bi-directional DC/DC converter is introduced in detail. Furthermore, the main working waveforms of the system under each working mode are verified by building a simulation experiment model using MATLAB/Simulink. The simulation results show that the system has advantages of high-voltage gain, low-voltage stress of switches and automatic current sharing between inductors.