# Optimization of Ship Permanent Magnet Synchronous Motor ADRC Based on Improved QPSO
## 5 Simulation Experiments and Results Comparison
As shown in Figures 15 and 16, the torque curve of the PMSM under QPSO-ADRC demonstrates significant advantages over PSO-ADRC. During startup, the torque under QPSO-ADRC is slightly higher than that under PSO-ADRC, but the fluctuations are much smaller, resulting in a smoother startup process. This indicates that QPSO-ADRC better handles instantaneous load changes during startup, reducing transient fluctuations and improving stability. After reaching a steady state, the torque fluctuations under QPSO-ADRC are much smaller than under PSO-ADRC. Specifically, torque fluctuations under PSO-ADRC are around 1.8 Nm, while under QPSO-ADRC, they are only about 1 Nm, showing higher steady-state accuracy and better torque stability. This difference is primarily due to the global optimization of ADRC parameters by the QPSO algorithm, which enables  
Figure 14: Speed Curve Comparison at 0.12 s.  
Figure 12: Speed Curve Comparison. Figure 13: Speed Curve Comparison at 0.1 s.  
the controller to better adapt to dynamic changes in the motor system, thereby reducing steady-state fluctuations. To verify the stability and efficiency of the proposed control method during operation, a Fast Fourier Transform (FFT) analysis was performed on phase A current at a fundamental frequency of 50 Hz. The results are shown in Figure 17. Total Harmonic Distortion (THD) is a critical indicator of both the system's power quality and the motor's efficiency. A comparative analysis of the THD values for different control strategies reveals that the THD values for PSO-ADRC, IPSO-ADRC, ICFO-ADRC, and QPSO-ADRC controls are 17.54%, 14.92%, 20.94%, and 13.48%, respectively. Under QPSO-ADRC control, the THD reduction rates are 23.1%, 9.7%, and 35.6%, respectively. The reduction in THD indicates a decrease in harmonic distortions and system instability, leading to smoother operation and lower losses, thereby enhancing operational efficiency. The experimental results provide strong evidence that, compared to conventional control strategies, the proposed method exhibits superior performance in terms of both motor efficiency and system reliability. To gain a deeper understanding of the performance differences among the control strategies, the speed and torque fitness values for the four algorithms were evaluated. Since the PMSM speed under ADRC control stabilizes quickly, and the error occurs only during a brief period, this compromises the accuracy of the fitness evaluation. As a result, the speed and torque fitness functions, which originally integrated the weighted error over the entire 0.6 s period to obtain a single output value, were modified. The new method sums the weighted error integrals over three specific time intervals: 0 to 0.05 s, 0.2 to 0.25 s, and 0.4 to 0.45 s. This adjustment enables a more accurate assessment of the system's error behavior. As shown in Table 3, compared to the PSO-ADRC, IPSO-ADRC, and ICFO-ADRC control  
Figure 16: QPSO-ADRC Control Torque Curve. Figure 15: PSO-ADRC Control Torque Curve. strategies, the speed fitness value decreased by 46.7%, 34.1%, and 69.9%, respectively, while the torque fitness value decreased by 50.8%, 36%, and 52.8%, respectively. These results demonstrate that QPSO-ADRC leads to a substantial reduction in both speed and torque fitness values under the same operating conditions, providing strong evidence that the proposed control method can significantly improve the control quality of the PMSM.