Open AccessFrequency support control of two‐stage photovoltaic grid‐connected system based on virtual governor
Author(s) -
Li Hui,
Tan Hongtao,
Bao Guangqing,
Xie Xiangjie,
Chai ZhaoSen,
Yang Tian,
Ding Kun
Publication year - 2021
Publication title -
iet renewable power generation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.005
H-Index - 76
eISSN - 1752-1424
pISSN - 1752-1416
DOI - 10.1049/rpg2.12161
Subject(s) - photovoltaic system , control theory (sociology) , duty cycle , maximum power point tracking , frequency deviation , maximum power principle , computer science , power (physics) , grid connected photovoltaic power system , grid , automatic frequency control , voltage , engineering , electrical engineering , mathematics , control (management) , physics , telecommunications , geometry , artificial intelligence , quantum mechanics , inverter
Given the urgent need for photovoltaic (PV) energy to participate in grid frequency regulation, a control strategy of the DC/DC converter of a two‐stage PV system based on the virtual governor (PV‐VG) is proposed in this paper. First, a one‐step PV maximum power point estimation (MPPE) method is proposed, which can obtain the reference voltage corresponding to the maximum power point and the power deload point, and some complex iterative calculations and sampling processes are circumvented. Then, based on the constant DC bus voltage of the two‐stage PV system, the coupling mathematical model of boost circuit duty cycle ( D ) and PV output power is established. According to the power setting and frequency deviation, the D is taken as the direct control target to reflect the direct coupling characteristics of D and grid frequency ( f‐D ) so that the PV system can adjust the output power reference independently according to the grid frequency deviation. Finally, a simulation model is built in Matlab/Simulink and RT‐LAB, and the results show that the accuracy of the proposed one‐step MPPE method is over 99.8%, and the correctness and efficiency of the PV‐VG control strategy are verified in some case study.