Frequency Characteristics and Reshaping Technology for Inveter-Based Generators Based on Virtual Synchronous Generator

doi:10.12204/j.issn.1000-7229.2022.02.013

Abstract

Abstract:

The difference in frequency characteristics between inverter-based distributed generators (DGs) and traditional synchronous generator-based DGs involved in frequency regulation in the microgrid (MG) may cause deterioration of the transition process of parallel operation and may cause system collapse. Aiming at this problem, this paper firstly conducts theoretical analysis and simulation on the frequency characteristics of the two types of DGs, and clarifies the differences in frequency characteristics of them. On this basis, the frequency characteristics of inverter-based DGs are reshaped applying virtual synchronous generator (VSG) technology and classic control theory, and the influence of reshaping parameters is analyzed. Finally, the parallel operation characteristics after reshaping are verified by MATLAB simulation, which proves the feasibility and effectiveness of the proposed method.

Key words: distributed generator(DG), synchronous generator, inverter, frequency characteristic, virtual synchronous generator(VSG)

CLC Number:

TM61

DONG Cun, TAO Yibin, ZHANG Moufa, WANG Shibai, SANG Bingyu, LI Zhijun, ZHANG Jiaan. Frequency Characteristics and Reshaping Technology for Inveter-Based Generators Based on Virtual Synchronous Generator[J]. ELECTRIC POWER CONSTRUCTION, 2022, 43(2): 109-116.

Figures/Tables 12

Fig.1 Typical structure of microgrid system

Fig.2 Frequency response model of a synchronous generator-based DG

Table 1 Specific parameters of the model

Fig.3 Transient output power of two generators

Fig.4 Generator disconnection due to transient overload

Fig.5 Control block diagram of VSG

Fig.6 Control block diagram of VSG rotor motion

Fig.7 Output power with traditional VSG control methods

Fig.8 Block diagram of active power-frequency control of improved VSG

Fig.9 Transient output power with different control methods

Fig.10 Transient output power of the inverter when J1 takes different values

Fig.11 Transient output power of the inverter when T1 takes different values

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