Authors: ŽELJKO HEDERIĆ, IVAN ALEKSI, BRUNO ŽULJ, MARIO ČAČIĆ, TIN BENŠIĆ, GORAN KURTOVIĆ, NIKOLA VEIĆ, MARIO SRNOVIĆ
Faculty: Faculty of Electrical Engineering, Computer Science and Information Technology Osijek
Country: Croatia
e-mail: zeljko.hederic@ferit.hr
The innovation consists in creating a model as a system of three electric drives that are mechanically coupled to be able to simulate different hybrid drives of vehicles and vessels with a mechanical and computer representation of energy flows. Mutually autonomously controlled electric drives (engine-generator drive system, gravity system, other drive sources) according to the parameters of real mechanical and electrical variables represent an advanced control system, whereby electric motors are mechanically coupled by a common shaft to ensure the reality of the mechanical coupling of real systems, and are also electrically connected to provide different patterns of electricity flows between the motor and the electric battery. The mock-up simulator can serve as an advanced simulator in the process of technological development of vehicle or boat propulsion, as well as for educational purposes of familiarization with very different systems of electric and hybrid vehicle and boat propulsion.
Current trends in the propulsion of vehicles and vessels are moving towards the use of electricity as the main source of energy for propulsion, as it’s highly efficient, easy to manage and offers the possibility of recuperating the kinetic energy from vehicles or vessels. If we add the trends towards the use of renewable energy sources (solar, wind, hydrogen, geothermal,…), there are numerous possibilities to combine energy sources and quantities, e.g. the possibility of energy storage through the regenerative operation of the electric propulsion engine as a generator. All the advantages of using hybrid systems are mainly based on efficient management of energy flows, which usually requires advanced models to capture the parameters of real devices and circuits and to determine realistic control parameters. Another important feature to be optimised is the use of the system over a longer period of time (modelling the trajectory of the vehicle or vessel taking into account terrain conditions – hills, ocean currents) with different external conditions (weather conditions, wet road, wind, sun). The third feature to be optimised is the availability of energy sources (e.g. refuelling stations at public ports).
All of the above data should be fed as input data into the model simulator, which links this data to the different parts of the propulsion system and performs simulations. All model motors are managed by a power electronics system that’s the possibility to connect to computer systems (e.g. MatLab Simulink, Siemens TIA Portal) where simulations of different propulsion systems of vehicles and ships, the preparation and realisation of signal and power flows according to the model simulator and the acquisition of feedback and performance information and finally the adaptation of these data for visual representations can be performed.
The model simulator for propulsion systems of vehicles and ships structurally consists of a room for three electric motors, a part for power electronics and switching technology, and a part for energy storage and storage of the visual parts of the model (monitor) during transport.
The system of three electric motors is divided into: a) a synchronous motor with permanent magnets as the most common form of drive due to its high efficiency and controllability b) an asynchronous motor used to simulate gravity (movement of vehicles uphill and downhill, movement of ships in water currents) c) an asynchronous motor used to simulate external driving forces (forces of combustion engines, gas and steam turbines, ship sailing, wind forces during driving).
To reduce the need for a large electrical energy tank, it’s envisaged that part of the energy consumed by the propulsion motor is fed back into the system via two asynchronous motors operating in braking mode, converting the mechanical energy of the propulsion into electrical energy. Various realistic scenarios can be created here. For ships, this can be an example of wind-driven sailing and energy recovery by propellers as water turbines and braking by water resistance when sailing in ocean currents. For vehicles, it can be the driving scenario of a serial hybrid electric vehicle driving uphill on a wet road with the wind blowing from behind. Here, it’s usually a matter of calculating the required energy and battery capacity, i.e. the required output and input power, because the entire system has up to seven different driving modes that have to be adapted to the different terrain and weather conditions.
The educational possibilities of the model simulator itself are very broad, as it offers several simulation levels (simple acceleration, driving at constant speed, … Consumption of the vehicle at standstill, the possibility of charging the batteries while the vessel is anchored in the flow of the river), which can be combined with different computer systems available on the market for simulating and visualisation of the movement of vehicles or vessels, allowing a multi-physical representation of the energy flows.
The model simulator is made of common, industrially available elements that are also used in other types of industrial plants, so that the final production costs, ease of maintenance and availability of spare parts are relatively favourable.
The model simulator was developed as part of the research carried out under the project “Research & Development of the Zero-Emission Passenger Sailing Ship” financed by the EU funds call “Increasing the development of new products and services arising from research and development activities – phase II” ( KK. 01.2.1.02.0127).