Switched Reluctance Machine Drives Based Electric Marine-Propulsion System

One of the major advantages of an electric propulsion system is the complete control of shaft speed without conventional mechanical arrangements such as gear-box and clutch. Also, this increases the system efficiency. Therefore, this paper presents a switched reluctance machine (SRM) based electric marine propulsion system. Initially, a small signal analysis is carried out due to the nonlinear and time varying characteristics of an SRM. Then, to control the shaft speed, this paper proposes a two-loop control scheme which consists of inner current and outer speed control loops. Here, an average current program mode scheme is used which ensures constant switching frequency unlike hysteresis controller. Also, a scheme for regenerative braking is presented to replace a lossy mechanical-braking system. Finally, numerical simulation results are presented to validate the proposed control scheme.