Modelling and simulation of tidal energy generation system

Abstract

Nowadays, most of the global electricity generation comes from fossil fuels. With consequent economic burdens and environmental pollution which is caused by the consumption of fuels which creates global warming. Therefore, tidal energy may play a tremendous role in mitigating this carbon dioxide due to its cleanest and most abundant energy source, as well as its cheap price. However, its output power variation with the serious variation of tides causes major power quality problems. This work focused on modelling, simulation and control of tidal energy from a tidal energy generation system in which the power output is challenged by problems such as harmonics, frequency fluctuations, and voltage sags since electricity users can introduce the harmonics onto the supply voltage waveform by non-linear loads. The system has been composed of a 1.5 MW/VDC, a 1.2 MW three-level inverter with a nominal voltage of 600 V, and an inductance (LCL) filter which are connected after inverters receive power from a permanent magnet synchronous tidal generator and connected to a DC load. It has been expected that the inverter will produce harmonic distortion of less than 0,5% and achieve 85%.The same nonlinear controller used in wind turbine applications stand for (PMSG) will be based to adjust the tidal energy system. However, high-speed simulations of circuit-oriented electric and electronic systems have been chosen. The generator power output can be optimised by utilising various control methods that have been proposed to control the voltage and the frequency. The Voltage Oriented Control is a technique that relies on high-level performance DQ‐coordinate controllers. This technique for a three‐phase boost rectifier has been created and simulated. The system simulation has been executed using the MATLAB /Simulink program. The controller, that is, a current controller and a DC‐link voltage controller, has been designed by Internal Model Control method. The presentation of the simulation results has been done and the control evolution of the system performance in response to the load and DC-bus voltage step changes. Two scenarios have been considered relying on the load conditions to analyse the development of the system performance’s case, the tidal array energy generation generates less power which did not reach the load demand, then the grid was injecting into tidal array energy generation system. In the last scenario, the tidal array generation is higher than the load, then the surplus of energy has been exported into the grid. Therefore, the intermediate circuit voltage and the high voltage ripple in the input line currents become unacceptable when the control system is not activated.It is demonstrated in this work that the Tidal energy system connected to the grid presents a good performance with a low total harmonic distortion around 0.12% for the voltage and 0.07% for the current. The validity and performance of the preferable control method have been verified by simulation results and correspond with what has been expected. The simulation results demonstrate that the controller can stabilise the constant dc-link voltage under the dynamic and steady-state performance of the system.