Analysis of Effect of Increasing Motor Voltage from 690-V to 1000-V on 1.5-MW Motor Drive Design for Large-Scale Electric Propulsion Ship

For large-scale electric propulsion ship, line voltage of independent microgrid in the ship can be increased from 690-V to 1000-V to reduce filter weight of grid-side systems. This paper investigates the advantages and disadvantages in terms of 1.5-MW motor drive design when the rated motor voltage is increased from 690-V to 1000-V. The analysis is performed in the order of induction motor, DC-link capacitor, and switching device for motor drive. The simulation results from MATLAB/SIMULINK are expressed by map considering various motor operating conditions. For fair comparison, the cost analysis is also conducted. As a result, this study finds that the motor drive loss and switch junction temperature are reduced, but the motor drive efficiency is also decreased at low-speed and low-torque operating condition. Therefore, we conclude that there is the need for research about improvement of motor drive efficiency at this operating condition.