## 5 Verification
### Simulation Conditions and Parameters  
The parameters are determined based on the small signal analysis [24; 25] and the inertia matching method (in Section 4.2). The final system parameters are shown in Table 1.  
Then the microgrid model shown in Figure 17 is established in MATLAB/Simulink according to Table 1.  
The photovoltaic cell type is First Solar FS-380. MPPT is achieved by the perturbation and observation method [26]. The battery used in the energy storage unit is a Nickel-Metal Hydride battery. The bidirectional half-bridge topology in Section 3.3 is adopted for the topology of the bidirectional chopper. The converter is of IGBT/Diode type with the control scheme in Section 3.4. The microgrid is modeled by Synchronous Machine Grid Equivalent Model proposed in Section 4.1.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Parameters** & **Values** \\ \hline \multirow{7}{*}{Parameters of system} & The maximum output power of the PV array, \(P_{\mathrm{max}}\) & 10 kW \\  & The rated capacity of the PV storage virtual synchronous generator system, \(S_{\mathrm{IN}}\) & 20 kVA \\  & The rated capacity of microgrid, \(S_{\mathrm{2N}}\) & 80 kVA \\  & The initial state of charge of the energy storage, SOC & 70\% \\  & The reference value of DC voltage, \(U_{\mathrm{dc}}\)* & 750 V \\  & The rated phase voltage of power system, \(U_{\mathrm{rf,ph}}\) & 220 V \\  & The sampling frequency of power system, \(f_{\mathrm{S}}\) & 10 kHz \\  & The rated frequency of power system, \(f_{\mathrm{S}}\) & 50 Hz \\ \hline \multirow{7}{*}{Filter parameters} & The series inductance of the filter, \(l_{\mathrm{S}}\) & 1.00 mH \\  & The parallel capacitance of the filter, \(C_{\mathrm{S}}\) & 500 uF \\  & The series resistance of the filter, \(R_{\mathrm{S}}\) & 0.01 \(\Omega\) \\ \hline \multirow{2}{*}{Line parameters} & Line inductance, \(l_{\mathrm{s}}\) & 1.00 mH \\  & Line capacitance, \(C_{\mathrm{s}}\) & 0.01 uF \\ \hline \multirow{7}{*}{Control parameters} & The active droop coefficient of the PV storage system, \(R_{\mathrm{P1}}\) & 0.0001 \\  & The reactive droop coefficient of the PV storage system, \(R_{\mathrm{P2}}\) & 0.00025 \\  & The proportionality factor of PQ control power outer loop, \(P_{\mathrm{r,PQ}}\) & 6 \\  & The integration factor of PQ control power outer loop, \(P_{\mathrm{r,PQ}}\) & 15 \\  & The proportionality factor of PQ control current inner loop, \(P_{\mathrm{r,PQ}}\) & 3 \\  & The integration factor of PQ control current inner loop, \(I_{\mathrm{r,PQ}}\) & 0 \\  & The proportionality factor of power outer loop in voltage and current double closed-loop control, \(I_{\mathrm{r,UL}}\) & 4 \\  & The integration factor of power outer loop in voltage and current double closed-loop control, \(I_{\mathrm{r,UL}}\) & 17 \\  & The proportionality factor of current inner loop in voltage and current double closed-loop control, \(I_{\mathrm{r,UL}}\) & 5 \\  & The integration factor of current inner loop in voltage and current double closed-loop control, \(I_{\mathrm{r,UL}}\) & 1 \\  & The virtual Inertia of the PV storage virtual synchronous generator system, \(I_{\mathrm{1}}\) & 0.9 kg\(\cdot\)m\({}^{2}\) \\  & The virtual Inertia of the Synchronous Machine Grid Equivalent Model, \(l_{\mathrm{2}}\) & 3.6 kg\(\cdot\)m\({}^{2}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Table of simulation parameters.  
Figure 17: Simulation model structure diagram.  
Generator mode conditions have an initial load of 60 kW and dispatching a value of 10 kW (PV storage virtual synchronous generator system output active power 10 kW in generator mode). Then the load suddenly drops to 40 kW at the 2 nd second.  
Motor mode conditions of an initial load is 60 kW, dispatching value \(-\)10 kW (PV storage virtual synchronous generator system absorbs active power 10 kW in motor mode). Then the load suddenly drops to 40 kW at the 2 nd second similarly.