System and method for starting an electric motor of a propulsion unit

摘要

The system comprises a main engine (10) driving a first main propeller (12) and a generator (20) controlled by an excitation circuit (40), a propulsion unit (30) comprising an electric motor (33) driving a second, contra-rotating propeller (35), and a control circuit (60) controlling the excitation circuit (40) and receiving as input signals at least the rotation speed (N) and the voltage (U) of the electric motor (33). The control circuit (60) calculates the torque (T) of the electric motor (33) based on said measured values and regulates the excitation circuit (40) in order to supply a lower voltage (U) to the electric motor (33) during the start up procedure.