| With the increasing consumption of fossil fuels,photovoltaic power generation has developed rapidly.However,the use of power electronic devices in optical storage microgrids has led to difficulties in the power system,such as weak inertia support,weak frequency regulation,and poor damping characteristics.Due to VSG technology being able to provide virtual inertia and damping support for stable operation of the power grid,it has been widely applied.This research establishes a simulation model for optical storage microgrids,and analyzes and verifies control strategies such as coordinated control of optical storage power and VSG parameter fuzzy control.Firstly,the principle of synchronous machine control was analyzed,and a VSG ontology control model was constructed through virtual rotor,virtual governor,virtual exciter design,and voltage and current dual loop control.The small-signal modeling of VSG control grid connection is established,the influence of virtual inertia and damping on the dynamic stability of the system is analyzed from the zero pole diagram of the transfer function,and the influence of virtual inertia and damping on the regulation time and overshoot of the system in the under damping state is analyzed from the perspective of active power step analysis.Secondly,models of photovoltaic power generation unit and energy storage unit were established,and two control strategies(MPPT control and power reduction control)and bidirectional DC/DC control strategy of energy storage unit were analyzed.MPPT control was implemented based on disturbance observation method.Four working modes were proposed based on the weather conditions of photovoltaic units and the SOC status of energy storage batteries,and power coordination control strategies were proposed based on three common working modes and verified through simulation.Finally,the influence of virtual inertia and damping on the dynamic performance of the system was analyzed based on the power angle curve and frequency curve.On the basis of establishing a VSG fuzzy control model in the optical storage microgrid connection mode,the maximum and minimum virtual inertia values were determined based on the maximum frequency change rate and energy storage characteristics.Fuzzy control rules were established by analyzing the relationship between virtual inertia and damping,frequency deviation,and frequency change rate.The fuzzy control strategy proposed in this paper was compared with fixed parameter VSG and conventional adaptive VSG through Matlab/Simulink,verifying the superiority of the proposed strategy. |
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