To study the technology of marine energy-saving and emission reduction,an optimal control strategy of induction motor is described for marine main engine waste heat utilizing system.The energy-saving system utilizing waste heat,which consists of turbocharger and induction motor,is analyzed;LQG optimal controller which employed dynamic model of exhaust gas turbocharger-induction motor is designed,and the energy feedback control of induction motor is realized.Mathematical simulation and hardware-in-the-loop experimental results show that reversible induction motor can enhance the dynamic performance of turbocharger.The proposed control scheme effectively harmonizes the relationship between rotor speed and the instability in main engine exhaust gas,and improves the dynamic response,stability and waste heat utilizing efficiency of exhaust turbocharger system.