1. Ship motor operating conditions and environmental requirements

Ship propulsion systems face harsh operating conditions for a long time:

Environmental challenges: high humidity, salt spray corrosion, temperature fluctuations (-20℃ to 50℃), vibration and shock;

Performance requirements: high efficiency (sensitive to energy consumption during continuous navigation), high power density (limited ship space), low noise (passenger ship comfort requirements), fast dynamic response (emergency maneuvering requirements);

Reliability requirements: long life (more than 10 years), low maintenance (difficult to frequently overhaul ocean operations).

2. Technical advantages of permanent magnet motors over asynchronous motors

Based on the special working conditions of ships, permanent magnet synchronous motors (PMSMs) exhibit the following core advantages:

Comparison dimensions	Permanent magnet motor	Asynchronous motor
Efficiency and energy consumption	Full load efficiency reaches 97%, and partial load efficiency is still over 90%	Full-load efficiency is about 92%, and low-load efficiency drops sharply to below 80%
Power density	Volume is reduced by 40%, and power density is increased by 50%	Large volume, the same power requires a larger installation space
Dynamic response	Torque response time <5ms, accurately matching the propeller speed change requirements	Response delay> 50ms, which can easily cause propulsion system oscillation
Noise and vibration	Electromagnetic noise is reduced by 20dB, and mechanical vibration is reduced by 30%	High-frequency electromagnetic noise is significant, requiring additional sound insulation design
Environmental adaptability	IP68 protection + salt spray resistant coating, brushless design eliminates spark hazards	Protection level is generally IP55, brushes are easily corroded by moisture
Maintenance cost	Brushless/slip ring structure, maintenance cycle extended to 5 years	Brushes are replaced every 1-2 years, and bearings are frequently maintained

3. Innovative application of permanent magnet motors in the field of ships

1. All-electric propulsion system

Application scenario: integrated electric propulsion of luxury cruise ships and military ships;

Advantages: Eliminate traditional drive shafts, improve layout flexibility, and achieve 85% propulsion efficiency;

Case: Royal Caribbean’s “Wonder of the Seas” uses 4×20MW permanent magnet propulsion motors, saving 15% fuel.

2. Podded propulsion device (POD)

Technical breakthrough: permanent magnet motor directly drives propeller, 360° vector steering;

Benefits: maneuverability is improved by 50%, and port berthing time is shortened by 30%.

3. Hybrid power system

Mode innovation: permanent magnet motors work together with diesel engines/fuel cells to achieve “zero emission” mode;

Case: Japan’s “e5” hydrogen fuel cell ship is equipped with permanent magnet motors, with a cruising range of 800km and zero carbon emissions.

Permanent magnet motors can be promoted across industries.

Industry	Application scenarios	Core Value
Deep-sea equipment	Unmanned underwater vehicle (AUV) propulsion	High power density supports long flight time, with a pressure resistance of 6000m
Port machinery	Cable crane drive	Precise positioning control (error <1mm), energy consumption reduced by 25%
Marine energy	Tidal current generator set	Low-speed direct drive design, annual power generation increased by 30%
Polar transport	Icebreaker auxiliary propulsion	-40℃ low-temperature starting capability, torque fluctuation suppression technology
Fishing vessels	Trawler winch power system	High overload capacity (200% rated torque for 1 minute)

Conclusion

Permanent magnet motors are reshaping the technical landscape of ship propulsion systems with their high efficiency, high reliability and environmental adaptability. From 10,000-ton giant ships to deep-sea probes, their application boundaries are constantly expanding. With the upgrading of green shipping and intelligent demand, permanent magnet technology will become the core driving force for the shipbuilding industry to move towards a zero-carbon future and release its potential in more high-end equipment fields.