Stand-alone hybrid power plants based on renewable energy sources are becoming a more and more interesting alternative. However, their management is a complex task because there are many variables, requirements and restrictions as well as a wide variety of possible scenarios. Though a proper sizing of the power plant is necessary to obtain a competitive cost of the energy, smart management is key to guarantee the power supply at a minimum cost. In this work, a novel hybrid power plant control strategy is designed, implemented and simulated under a wide variety of scenarios. Thereby, the proposed control algorithm aims to achieve maximum integration of renewable energy, reducing the usage of non-renewable generators as much as possible and guaranteeing the stability of the microgrid. Different scenarios and case studies have been analyzed by dynamic simulation to verify the proper operation of the power plant controller. The main novelties of this work are: (i) the stand-alone hybrid power plant management regarding a battery energy storage system as a part of the spinning reserve, (ii) the characterization of the largest loads as non-priority loads, (iii) the minimization of the needed spinning reserve and fuel consumption from diesel generators.

Switching in power semiconductors with emerging materials such as silicon carbide (SiC) leads to undesired overvoltages and oscillations that limit switching frequency, largely due to impedance in the current commutation loop. Minimizing this parasitic impedance in printed circuit boards (PCB) requires precise characterization. To this end, this work presents a new measurement method based on obtaining S-parameters with a vector network analyzer (VNA) and on using a shielded flexible probe with mobile test terminals. The flexible probe uses a metal shielding plane perpendicular to the PCB to prevent the main measurement errors resulting from the variation in the magnetic flux responsible for loop inductance during the VNA frequency sweep. The proposed curve-fitting procedure consists of measuring the characteristic impedance and propagation time of the traces, considering they form ideal transmission lines. These values are used for a nonlinear least squares adjustment for the actual line (with losses). Finally, an experimental assembly with microstrip transmission lines was developed to validate the proposed method experimentally. The experimental results were compared with those obtained by using a rigid test fixture as a reference, those calculated analytically and those obtained from partial element equivalent circuit (PEEC) simulation. The curve-fitting method yields better results than the analytical and the simulation methods and they exhibit (up to 350 MHz) precisions of 1.37% in the characteristic impedance measurement and of 0.81% in the propagation time.

This work begins with the initial design of an LCL filter for a 20 kW SiC inverter, and its response is experimentally analysed from the perspective of grid quality. Based on these results, a sensitivity analysis is carried out by varying the parameters of the RC branch. The objective is to identify the RC branch that achieves maximum efficiency in harmonic content reduction, as well as minimising losses. The conclusions drawn relate to the sizing of the LCL filter and the various possibilities for its optimisation. The conclusions presented have been obtained with regard to the sizing of the LCL filter and the different possibilities for its optimisation.