Development of an efficient propulsion motor and driver for use in the deep ocean

Autosub is a NERC Community Research Project being hosted by the Institute of Oceanographic Sciences Deacon Laboratory. The aim is to develop an autonomous underwater vehicle capable of operating to full ocean depth which will collect data for the purposes of oceanographic science and climate forecasting. In order to maximise, the mission length, the vehicle should have a high energy density source and above all, be reliable. Deep submergence propulsion motors typically comprise a motor running in pressure compensating oil, a reduction gearbox and an output shaft passing through a shaft seal. The losses resulting from a fast running motor stirring the oil, gearbox inefficiencies and seal friction typically result in a low overall efficiency. This paper presents the progress being made in developing a 1.6 kW contra rotating brushless DC motor, a key element in an energy efficient propulsion system. The authors discuss the design of the test dynamometer, the test method, and performance results in shallow water