Design and construction of a four-channel interleaved buck dc/dc converter for an electric boat application

This paper focuses on the design and construction of an electric drive system for an electric boat. A number of technical interventions were made to convert a simple boat to an electrically driven boat. In our days the electric boats and the electric propulsion in general constitute a part of the electric transportation. The electric transportation seems to be an alternative solution in the continuously increasing demand in the sector of transports as well as in energy and environmental problems. The high efficient electric machines and power electronic converters, the high control level of power electronics that offers manoeuvrability in a ship, the lack of noise - disturbance and the absence of pollution lead to the use of electric propulsion in boats and ships more and more nowadays. In the application, on account of practical and safety reasons we were led to the choice of a low voltage permanent magnet direct current (DC) motor. This is resulting to a high value of current to get the nominal power of 1.5 kW. For this reason an interleaved four - channel dc/dc converter was designed and constructed which has the ability to control high currents and can be considered as ideal for such type applications. The particular converter is constituted by 4 parallel channels, it is working in the continuous conduction mode (CCM) and it decreases the voltage of 36 V to 0-24 V to control the velocity of the dc propulsion motor which its full load current is 78 A. Firstly, simulation via PSpice program and also a number of experiments have been made to investigate the operation of the converter. The experiments show that the efficiency of the interleaved converter of the application is about 95 %, so it is a good solution for driving low voltage - high current dc motors. Such types of electric motors are used in electric transportation applications. The launching of the boat “PROTEUS” and a number of sea tests show the advantages of the electric propulsion.