**4. Conclusions**

Based on the current situation that a low-voltage high-current generation system focuses mainly on rectifying the voltage of the power grid, the present study proposes a synchronous generator system with a multiple three-phase permanent magnet, which is controlled by the Lyapunov algorithm. Through analysis, there is a problem of mutual coupling between the control variables. To solve this problem, a simple decoupling method was adopted. By decoupling, the Lyapunov derivative of the

system is always negative, thus ensuring the stability of the system. Since the direct power control method and dead-beat algorithm are widely used, in this paper, these two methods were used to compare the performance. The simulation results show that when the Lyapunov algorithm is utilized for the synchronous generator system with a multiple three-phase permanent magnet, the system has low voltage overshoot, and reasonable dynamic and static performance. It is found that system stability is not disturbed by large signals and has reasonable performance for the unit power factor. The experimental results are consistent with the simulation, which proves that the control strategy is an effective and reliable control scheme.

**Author Contributions:** Conceptualization, J.L. and X.T.; methodology, J.L. and X.T.; software, X.T.; validation, J.L. and X.T.; formal analysis, J.L. and X.T.; investigation, J.L and X.W.; writing—original draft preparation, J.L. and X.T.; writing—review and editing, J.L and X.T.; visualization, H.H.-C.I.; supervision, H.H.-C.I.; project administration, X.W.; funding acquisition, X.W. and J.L.

**Funding:** This research was funded by National Natural Science Foundation of China, gran<sup>t</sup> number 51177031.

**Conflicts of Interest:** The authors declare no conflict of interest.
