Research on noise suppression method of underwater propulsion motor based on periodic-phase-variation hybrid spread spectrum modulation

In this paper, a periodic-phase-variation hybrid spread spectrum modulation (PPVH-SSM) method is proposed to suppress the electromagnetic noise interference of underwater propulsion motors (UPM). Given the problem that the traditional spread spectrum modulation method is difficult to select parameters due to the contradiction between the spread spectrum bandwidth and the degree of harmonic suppression, resulting in the problem that the method cannot effectively suppress noise interference, the author first analyzes the disadvantages of the traditional method, that is, it cannot make full use of the frequency points within the given bandwidth to disperse harmonic energy. Secondly, the harmonic mathematical model after the proposed PPVH-SSM method is deduced through mathematical formulas. It is theoretically proved that the technique has more harmonic frequency points in the specified frequency band, and the reason why the new method can have a larger bandwidth under the premise of the same harmonic suppression degree is analyzed and proved. In the Matlab/Simulink simulation process, the phase-locked method is used to ensure the stability of the phase transition. Finally, the effectiveness and superiority of the proposed method in suppressing the electromagnetic noise interference of the UPM are verified and compared.