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A multi-mode operation control method for photovoltaic - energy storage virtual synchronous machine to improve the system life
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  • Fang Liu,
  • zhongliang li,
  • xiaomeng wang,
  • Urfa Rasool
Fang Liu
State Grid Henan Electric Power Company Jiaozuo Power Supply Company

Corresponding Author:[email protected]

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zhongliang li
State Grid Henan Electric Power Company Jiaozuo Power Supply Company
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xiaomeng wang
State Grid Henan Electric Power Company Jiaozuo Power Supply Company
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Urfa Rasool
Research and Development department, TEMSTEC (pvt) Ltd,
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Abstract

The PV-storage virtual synchronous generator (VSG) is an emerging inverter control strategy for a weak grid; however, it is susceptible to random load perturbation, which causes unnecessary charging and discharging of energy storage, affecting its lifetime. In this paper, VSG selective input and output strategy is proposed to improve the lifespan of energy storage. The strategy comprises two PV-storage VSG operation modes and its power coordination control method. Firstly, the strategy of selective VSG input based on the disturbance size is proposed, and the VSG input moment is obtained by solving the system of model equations offline. The selective VSG start method is realized by matching changes in disturbance frequency online so that the grid can preferentially utilize the physical generator inertia. Secondly, the dynamic exit strategy of VSG control based on dynamic frequency characteristics is constructed to avoid the secondary throughput of PV-storage VSG during the frequency recovery phase after the grid is disturbed. It is necessary as the grid variation may affect the energy storage life and reduce frequency recovery speed. Finally, the correctness and effectiveness of the proposed scheme are verified by simulation and semi-physical experiment.