Utilizing green energy is a key area for research. In this Final Project the utilization of green energy for sailboats is investigated. The sailboats initially are equipped with internal combustion engines (ICE) that are used during leaving and returning to the port and for providing propulsion during lull. The up-to-date electric synchronous and asynchronous motors are robust and reliable, have excellent static and dynamic performance especially when supplied by DC/AC converters. They are produced in very large series, thus have low cost, and an outstanding advantage in this area that they do not pollute the environment. Two well-known renewable energy resources are solar and wind. Open water has advantages in capturing green energy, as practically no obstacles limit harvesting the solar or the wind energy. Using the harvested and stored energy, the electric motor can propel the ship. In this Final Project (FP) a novel system is introduced which utilizes solar and wind energy for ship propulsion.
In the first part, the technical background of the components and the basic operation of the system is described. These are the following: photovoltaic (PV) panels that are charging the battery through a DC/DC converter. Asynchronous machine and propeller, which either drives the boat or charges the batteries through a converter. Energy storage device, which supplies the energy to the induction machine. This battery is charged from the utility network in the harbour via an AC/DC converter (battery charger) and the harvested solar and wind energy.
After the technical background overview, commercially available products are selected. First a middle sized sailboat is chosen with an ICE. The electric motor drive system is designed by aiming at the rated power of the ICE., i.e. the components were chosen taking into account the power level of combustion engine and the cruising range.
Two kinds of computer simulation models have been developed and used for designing the drive system and studying the static and dynamic behaviour.
A simulation program was developed, which simulates the controlled movement of the selected boat and the technical performance. Furthermore the effect of the wind and solar irradiation is taken into account. The consumption of the stored energy is calculated in real time, which makes it possible to predict the remaining cruising distance with the actual charging level of the battery. The second type of simulation programs provides help for both hardware and software development. The motor speed is controlled using a microcontroller. The speed of the boat is set through a PC and the behaviour of the motor is examined. At the end the FP the economics of the system is calculated to determine the payback time, feasibility and viability of the system.