PMSM and 5-level CSI based boat electrical propulsion system efficiency analysis

This work evaluates an adjustable speed drive (ASD) designed for a 12 kW electrical boat propulsion system from the efficiency perspective. The ASD comprises a custom designed permanent magnet synchronous machine (PMSM) and a five-level current source inverter (5L-CSI). A PMSM with concentrated windings is evaluated using a design procedure based on analytical equations and non-linear optimization. The machine losses are obtained through finite elements magnetic fields calculations. The power converters conduction and switching losses are computed considering the machine and inverter models, which includes the effects of a space vector modulation strategy. Global and components efficiency figures are presented for different operation points. The paper shows that the maximum electrical efficiency of the system corresponds to 91%.