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This paper proposes a novel electric propulsion system for naval ships, which consists of Active Front End (AFE) converters directly connected to battery Energy Storage Modules (ESMs). Employing the proposed AFE converters with ESMs in the power systems of naval ships can enhance the reliability and quality of the electric power. Furthermore, the fuel-efficiency of the generator can be improved by a higher loading factor of the generator and its prime movers. The proposed AFE configuration does not require an additional dedicated DC/AC converter for the ESMs. Instead of that, the AFE converter itself can control the DC link voltage and the discharging and/or charging of the ESMs. A control scheme to achieve these control objectives is also presented in this paper. The overall power system, including the generators and electrical loads of a naval ship, is implemented by a small scaled Power Hardware-In-the-Loop (PHIL) simulator. Through this experimental setup, the proposed system configuration and the power control strategies are verified. It is shown that the fuel-efficiency and transient dynamics can be improved in the normal and contingency operation modes.

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This paper proposes a new sensorless method for a Synchronous Machine with an Inverter Integrated Rotor (SMIIR). The SMIIR is a newly developed machine based on the wound rotor synchronous machine (WRSM) but has no brushes and slip-rings. And conventional high-frequency signal injection sensorless methods are based on physical magnetic saliency. Therefore, conventional methods cannot be applied to the SMIIR which has no sufficient magnetic saliency. The proposed sensorless method suggests virtual resistance saliency created by the rotor-side inverter, whose axes can be placed arbitrarily. Based on this virtual saliency the rotor position information is included and excluded in the relationship between the highfrequency stator voltage and stator current. Because the SMIIR already injects high-frequency voltage for the power transfer,there is no need to inject additional voltage for the proposed high-frequency sensorless method. And initial +d axis detection algorithm using the rotor-side inverter without using magnetic saturation is also proposed. The feasibility of the proposed sensorless method was verified by experimental results with the prototype SMIIR.