The noise of the underwater Integrated Motor Propulsion System is one of its key performance indicators. During operation, it constitutes a complex noise system involving multiple significant noise sources such as the propeller, motor, and frequency converter. To investigate the main characteristic frequencies and causes of noise in this system, this paper analyzes the hydrodynamic noise, electromagnetic noise, and frequency converter noise formation principles of the Integrated Motor Propulsion System, along with experimental validation. The study reveals that the system exhibits significant low-frequency noise, with its primary characteristic frequencies being the 6th Harmonic and 12th Harmonic of the propulsion motor's fundamental frequency, which are the main contributors to noise. The frequency converter's switching frequency noise also shows localized peaks but is not the dominant contributor. No significant hydrodynamic noise characteristic frequencies are observed, indicating that the propeller is not the primary noise source.
Wang et al. (Sun,) studied this question.