DC circuit breakers must be able to arrest overcurrent conditions to prevent electrical equipment and wiring from causing building fires or other hazards from occurring. With more DC renewable sourced structures such as Cal Poly’s DC House, an inexpensive and reliable protection system is necessary to ensure safe energy transfer to the loads. One method of protecting a system is preventing excessive amounts of current to be drawn by the load when the surrounding components are rated at a lesser value. DC circuit breakers act as a monitoring system and barely presents an effect on the voltage or power. With most DC circuit breakers on the market being mechanical, the response time to an overload condition is limited to the speed the contacts can disconnect. The examination of response timing and overcurrent limiting is explored in this thesis when using a solid state based DC circuit breaker. The system is designed to handle 600 W, where the operating voltage is 48 V and the maximum allowable current is 12.5 A. The solid state DC circuit breaker has the capability of arresting excessive currents within 30 µs and can be reset through a single pole single throw switch.

The DC House project strongly relies on renewable energy sources to provide power to the house for various loads. However, when these sources are unable to provide power at a certain time, a back-up energy source from a battery must be readily available to fulfill the house’s power needs. This thesis proposes a bi-directional flyback power converter to allow a single-stage power path to charge the battery from and to discharge the battery to the DC House 48 V system bus. The design, simulation, and hardware prototype of the proposed flyback bi-directional converter will be conducted to demonstrate its feasibility. Results from a 35W prototype demonstrate the operation of the proposed converter for both charging and discharging purposes.