Protecting a Low Voltage Direct Current System Using Solid-State Switching Devices for DC Grid Applications

Date of Award


Degree Name

Doctor of Philosophy


Electrical and Computer Engineering

First Advisor

Dr. Johnson A. Asumadu

Second Advisor

Dr. Ikhlas Abdel-Qader

Third Advisor

Dr. Azim Houshyar


Direct Current System, solid-state switching devices, DC grid applications


The objective of this work is to protect low voltage direct current (LVDC) systems using solid-state circuit breakers (SSCBs) for grid applications. This goal was achieved using an insulated gate bipolar transistor (IGBT) designed with the addition of a custom design snubber circuit. Protection of LVDC was accomplished by detecting and isolating different types of DC faults in LVDC microgrid systems at the DC bus.

This research contributes a novel DC circuit breaker model that uses a magnetically coupled inductor. A comparison of different IGBTs in terms of overvoltage and switching time was considered. This research presents a model study of a low-voltage DC microgrid protection system during short circuit current, including the calculation and details of its components. Different short circuit faults were studied along with design equations for the different circuit parameters. Because SSCBs respond quickly to faults, they have been considered for these systems. Study and comparison of these protection devices will enable greater understanding of the need for such devices. The short circuit current based on available estimation method was calculated, and the results were compared between the simulations. This work contributes to a better understanding of LVDC short circuit protection and overvoltage. The simulation results were shown with and without the newly designed snubber circuit.

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