## 5 Simulation Results
### Oscillation Analysis Verification When Changing the Control Parameters of the Grid-Side Converter  
Figure 18 gives the simulation results when changing the control parameters of the grid-side converter. As it can be seen, when \(K_{\text{pv}}\) is changed to 2, the oscillation phenomenon observed in Figure 18a exhibits a noticeable reduction in intensity when contrasted with the curve presented in Figure 17. A similar result can also be seen in Figure 18c when \(K_{\text{pc1}}\) is changed to 8. As a result, these two control parameters have a weak performance in completely suppressing the oscillation. Therefore, \"\(\times\)\" is used to label them in Table 1.  
Furthermore, when \(K_{\text{iv}}\) is decreased to 20, the oscillation is completely suppressed, as shown in Figure 18b, to maintain the system's stability. Similarly, when \(K_{\text{ic1}}\) is decreased to 25, the oscillation also disappears, which indicates that reducing the relevant parameters can suppress the oscillation. Thus, \"\(\downarrow\)\" being used to label them in Table 1 is verified.  
Figure 17: Oscillation waveforms under the initial parameters.  
Oscillation Analysis Verification When Changing the Control Parameters of the Machine-Side Converter  
Figure 19 gives the simulation results when changing the control parameters of the machine-side converter. As it can be seen, when changing \(K_{\text{pw}}\), \(K_{\text{iw}}\), \(K_{\text{pc2}}\), and \(K_{\text{ic2}}\), the oscillations are hardly mitigated, and they show almost no changes compared to Figure 17. As a result, the control parameters of the machine-side converter have no ability to suppress the oscillations. Therefore, \"\(\times\)\" being used to label them in Table 1 is verified.  
Figure 18: DC-side voltage waveforms when changing the control parameters of the grid-side converter.  
Oscillation Analysis Verification When Changing the Excitation System and the Turbine Governor Parameters  
Figure 20 gives the simulation results when changing the excitation system and the turbine governor parameters. As it can be seen, just as in Section 5.2, when changing \(K_{\text{pg}}\), \(K_{\text{ig}}\), and \(K\), the oscillations are also hardly mitigated, and they show almost no changes compared to Figure 17. As a result, the excitation system and the turbine governor parameters have no ability to suppress the oscillations. Therefore, \"\(\times\)\" being used to label them in Table 1 is verified.  
Figure 19: DC-side voltage waveforms when changing the control parameters of the machine-side converter.  
Oscillation Analysis Verification When Changing the Equivalent Impedance Parameters of the Grid Network  
Figure 21 gives the simulation results when changing the equivalent impedance parameters of the grid network. As it can be seen, when decreasing \(L_{\text{g}}\), or increasing \(R_{\text{g}}\), the oscillations can be suppressed, and the system ultimately returns to a stable operating state. Therefore, \"\(\downarrow\)\" being used to label \(L_{\text{g}}\) and \"\(\downarrow\)\" being used to label \(R_{\text{g}}\) in Table 1 are verified.  
Figure 21: _Cont._  
Figure 20: DC-side voltage waveforms when changing the excitation system and the turbine governor parameters.