Modellazione e controllo del sistema di trasferimento di potenza wireless per la ricarica di veicoli elettrici

Gasoline accounts for 56% of the transportation fuel consumed, contributing to the industry's overall 29% energy consumption. Greenhouse gases are released into the atmosphere when gasoline is used extensively, endangering the ecosystem. Currently, there is an increasing attraction to EV technology due to their decreased carbon emissions, and it is anticipated that their quantity will increase significantly in the near future. The limited driving range of EVs is a big problem with implementation. This requires a continuous improvement in their charging infrastructure, namely wireless charging systems, designed for various private, commercial, and public uses, including both home and public charging stations. Wireless charging facilities can address the issues of wired charger connectivity, charging time, and range anxiety, which are the main obstacles to the widespread adoption of EVs. Wireless charging involves the transmission of power from a transmitting side to a receiving side without any physical touch, essentially enabling wireless power transfer (WPT). Nevertheless, the actual use of wireless charging infrastructure for EVs has encountered many technical obstacles. The primary obstacles to implementing the wireless charging system are a low coupling coefficient between the transmitter and receiver, misalignment between the charging pads of the transmitter and receiver, and potential interference from outside objects like metal or living organisms. As part of its evaluation, this dissertation models and compares several magnetic couplers for misalignment and coupling coefficient applications with and without shielding. In addition, it evaluates and contrasts several reactive compensation circuits that are well-suited to diverse applications in terms of efficiency, power factor, load independence, and misalignment tolerance. Following a comprehensive state of the art of WPT technology and a detailed depiction of a typical WPT system, the thesis next shifts its attention to modelling and control analysis of WPT systems. In summary, the objective is that the control system should provide a good tracking performance with respect to the battery voltage or current reference. This thesis primarily focuses on the modelling and control of the series-series (SS) compensated WPT system, which is typically a dc-dc converter and usually incorporates a feedback control to stabilize the system output. Small-signal equivalent circuit models are crucial for optimizing control variables to develop a high-performing controller. The small signal model for an SS-WPT system is first implemented with generalized state space averaging method and simulated results validated the mathematical model with a close agreement. The proposed small signal modelling for the SS-WPT system is based on the extended describing function. The order of the small signal equivalent model resulted five, and the model can well predict the low frequency response of the original system. All the small-signal characteristics of the intended system can be thoroughly studied thanks to these circuit models. Also, the small-signal model is used to analyse the explicit input to output voltage transfer function and their state space equations. Using the reduced order small signal model state space equations, it was possible to work on control strategy with optimized control variables. A full-order state observer based on state feedback controller using pole placement and LQR techniques to control the output voltage of an SS-WPT system has been implemented. The requirements about the system's maximum overshoot and the time it takes to settle down are used to figure out the controller poles locations. The simulation result using the step input shows that the closed loop response settles at steady state with a satisfactory trajectory.