## 7 Conclusions  
In this paper, the impact of the phase difference between the carrier waves of VSIs on the dc-link capacitor current in dual-axis PMSMs drivers was investigated. The harmonic component of the three-phase VSIs controlled by the SVPWM technique was analyzed using the double Fourier analyses method. The second carrier harmonic component is the significant harmonic component of the dc-link capacitor current, and the carrier wave phase shifting method was proposed to eliminate this harmonic component for the dual three-phase VSI dual PMSMs system. The optimum angle between carrier waves, which is \(\pi/2\) rad, was determined using the mathematical analysis of the second carrier harmonic component in order for maximum cancellation of the second carrier harmonic, and thus a maximum reduction in the dc-link capacitor current. The proposed method was simulated for different operating conditions of the PMSMs to prove that the proposed method can be applied for all conditions. The mathematical model and simulation results were verified by the experimental results. It was demonstrated that a phase difference of \(\pi/2\) between the carrier waves reduces the magnitude of the second harmonic, leading to a 60% reduction in the dc-link capacitor current. In addition, the dc-link capacitor temperature was reduced by 20 \({}^{\circ}\)C. Both the simulation and experimental results indicate that the reduction in the dc-link capacitor current is maximized when both PMSMs operate under the same conditions. Even under different operating conditions of PMSMs, the proposed method significantly reduces the capacitor ripple current by partially cancelling the second carrier harmonic components, resulting in a noticeable improvement compared to the standard approach.  
It is also expected that the proposed method, by reducing the harmonics of the input current, will improve the electromagnetic interference (EMI) performance of the motor driver unit. However, this issue can be further investigated in future research through detailed electromagnetic interference and electromagnetic compatibility (EMI/EMC) testing of the motor driver unit under various operating conditions. Moreover, we recommend conducting more analysis about the overall efficiency and total harmonic distortion. In addition, only the SVPWM technique is researched in this article. Further research should focus on the other PWM techniques to determine the optimum phase shift angle. Moreover, comparisons with the other current reduction methods such as active compensation or SVPWM compensation should be considered in future studies. Further studies should also analyze the economic impact of the proposed method, especially in terms of reducing the size and cost of the dc-link capacitor.  
Conceptualization, D.S. and B.D.; methodology, D.S. and B.D.; software, D.S.; validation, D.S. and B.D.; formal analysis, D.S.; investigation, D.S.; resources, D.S.; data curation, D.S.; writing--original draft preparation, D.S.; writing--review and editing, D.S. and B.D.; visualization, B.D.; supervision, B.D.; project administration, B.D.; funding acquisition, D.S. and B.D. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
The authors would like to thank ASELSAN, whose support made this work possible.  
The authors declare no conflicts of interest.