Nowadays, due to the advancements in power electronics, technological improvements in DC loads and motors, and continually increasing interest in the use of renewable energy sources, DC systems are gaining enormous popularity. They are used in many applications including the fast-charging stations for electric vehicles, DC-powered homes, aircraft, and telecommunications power systems. Moreover, replacing the traditional AC grids with DC microgrids could introduce several advantages such as lower energy generation cost, and higher reliability and efficiency. Despite all the advantages offered by DC grids, their protection devices still suffer from several difficulties. The protection devices can be divided into two main groups including the mechanical circuit breakers and the solid state circuit breakers. The former provides a highly efficient protection for DC systems, but it needs frequent maintenances and has a relatively slow operation. In contrast, the latter offers a quick fault interruption, and it also provides a reliable protection against DC faults, but it causes high power losses during the normal current conduction. To obtain an adequate solution for DC applications some hybrid breakers have been proposed in the latest research papers; however, the previous solutions introduce several issues, and usually, their lifetime decreases dramatically after every short circuit occurrence. In this thesis, besides surveying some of the recent hybrid circuit breakers, two new configurations are proposed and the procedure to dimension all the active and passive components in the devices is analyzed. Finally, the operability of the proposed breakers is proven through the simulation results and the necessary considerations for designing the PCB of the second model are presented.
Oggigiorno, grazie ai progressi nell'elettronica di potenza, ai miglioramenti tecnologici nei carichi e nei motori DC e al crescente interesse per l'uso di fonti di energia rinnovabile, i sistemi DC stanno guadagnando enorme popolarità. Sono utilizzati in molte applicazioni, comprese le stazioni di ricarica rapida per veicoli elettrici, case alimentate in corrente continua, aeroplani e infrastrutture di telecomunicazioni. Inoltre, la sostituzione delle tradizionali reti AC con microgrid DC potrebbe introdurre molteplici vantaggi come un minor costo di generazione di energia e una maggiore affidabilità ed efficienza. Nonostante tutti i vantaggi offerti dalle reti DC, i loro dispositivi di protezione presentano ancora diverse difficoltà. I dispositivi di protezione possono essere suddivisi in due gruppi principali, gli interruttori automatici meccanici e gli interruttori allo stato solido. I primi forniscono una protezione altamente efficiente per i sistemi DC, ma necessitano di frequenti manutenzioni ed hanno un tempo di intervento relativamente lento. Al contrario, i secondi forniscono una rapida interruzione del guasto e sono una protezione affidabile contro i guasti, ma provocano elevate perdite di potenza durante la normale conduzione della corrente. Per ottenere una soluzione adeguata per applicazioni in DC, alcuni interruttori ibridi sono stati proposti in letteratura scientifica; tuttavia, le soluzioni finora individuate presentano diversi problemi e, di solito, la loro vita diminuisce drasticamente dopo ogni evento di cortocircuito. In questa tesi, oltre a rilevare alcuni dei recenti interruttori ibridi, vengono proposte due nuove configurazioni e viene analizzata la procedura per dimensionare tutti i componenti attivi e passivi dei dispositivi. Infine, l'operabilità degli interruttori proposti è dimostrata attraverso i risultati di simulazione e vengono presentate le considerazioni necessarie per la progettazione del PCB del secondo modello di interruttore.
Design of bidirectional hybrid DC circuit breaker
HAGHNAZARI, HOSSEIN
2019/2020
Abstract
Nowadays, due to the advancements in power electronics, technological improvements in DC loads and motors, and continually increasing interest in the use of renewable energy sources, DC systems are gaining enormous popularity. They are used in many applications including the fast-charging stations for electric vehicles, DC-powered homes, aircraft, and telecommunications power systems. Moreover, replacing the traditional AC grids with DC microgrids could introduce several advantages such as lower energy generation cost, and higher reliability and efficiency. Despite all the advantages offered by DC grids, their protection devices still suffer from several difficulties. The protection devices can be divided into two main groups including the mechanical circuit breakers and the solid state circuit breakers. The former provides a highly efficient protection for DC systems, but it needs frequent maintenances and has a relatively slow operation. In contrast, the latter offers a quick fault interruption, and it also provides a reliable protection against DC faults, but it causes high power losses during the normal current conduction. To obtain an adequate solution for DC applications some hybrid breakers have been proposed in the latest research papers; however, the previous solutions introduce several issues, and usually, their lifetime decreases dramatically after every short circuit occurrence. In this thesis, besides surveying some of the recent hybrid circuit breakers, two new configurations are proposed and the procedure to dimension all the active and passive components in the devices is analyzed. Finally, the operability of the proposed breakers is proven through the simulation results and the necessary considerations for designing the PCB of the second model are presented.| File | Dimensione | Formato | |
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Design of Bidirectional Hybrid DC Circuit Breaker.pdf
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https://hdl.handle.net/10589/174269