Comparison of Submarine Drive Topologies Using Multiobjective Genetic Algorithms

A multiobjective genetic algorithm (MOGA) is used to compare submarine propulsion concepts and seek out tradeoffs in their design. Concepts include the novel integrated electric propulsion (IEP) concept and hybrid steam turbine and electric motor drive. System design and supervisory controllers are optimized under multiple operating conditions to give maximum propulsive efficiency. The advantages of each propulsive topology are compared, along with tradeoffs in their design. The hybrid steam turbine/electric motor drive is found to give superior propulsive efficiency compared with pure mechanical and pure electrical drive topologies. The optimal hybrid drive system design favors a large steam turbine and smaller electric motor, which is utilized during slow cruise speeds and top speed cruising only. Optimization of the supervisory controller simultaneously with the system design is found to give improvements in overall propulsive system efficiency.