Fast Braking Control of Ship Hybrid Propulsion System

Ship hybrid propulsion system has been more and more popular in small-to-middle sized riverboats, ‘river and sea’ boats and coaster crafts, because of its high flexibility and efficiency. However, this hybrid power ship normally needs to reverse the main engine to asternway, in the braking period the main engine will even stop inj ection so as to shut its output torque off, which extends the braking time. In view of this phenomenon, this paper analyses the torque characteristics of propeller in the braking period by simulation. On the basis of propeller torque characteristics study, a MTPA(maximum torque per ampere) control method of shaft motor and the supercapacitor reserving mode is proposed to absorb braking energy, thus reducing braking time.