Hybrid propulsion testing using direct-drive electrical machines for super yacht and inland shipping

Hybrid or full electric propulsions for inland ships are becoming more popular. In these application, direct-drive PM propulsion motors are a preferred machine configuration. This paper discusses the challenges to determine the losses, as estimated with simulations, during the testing procedures of a 350kW at 300rpm, respectively. The full-load testing of the drive system is performed by mechanically coupling two identical machines, of which one operates as a motor and the other as a generator, or "back-to-back" testing configuration. Two Direct-Drive PM machines have been manufactured to validate key findings from the modelling, particularly in terms of loss predictions, thermal modelling and influence of the design features such as magnet segmentation. A back-to-back set-up is created for testing these machines with a speed range of 0-450 rpm. Before the measurement commended, tests were carried out in accordance with IEC60034-1, IEC60034-15, IEC60085-1, IEEE43, IEEE118 and Lloyd's register. These tests included: surge, resistance, winding symmetry, high voltage test, insulation resistance and polarization index. All these tests were successfully completed and agreed with the analysis as described before. Following the motors have been installed in an inland ship hybrid propulsion.