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An optimal design of a 2-MW dc supply with a variable output dc voltage range between 400 V and 1500 V, and intended for testing equipment under IEEE 1547 is presented in this paper. Trade-offs between size and system complexity must be taken into account because the main components (dc inductor, semiconductor switches, cooling system, etc.) of such a high power system are expensive and/or bulky. Several dc-dc converter topologies are evaluated and compared for the intended application, and all the components are selected based on current market availability. The 4-stage interleaved dc-dc converter topology is selected since it has a good performance-to-price ratio. Challenges of operation under both heavy and light loads are addressed. The control algorithm for this topology is presented and illustrated using simulation results. These simulations demonstrate that the proposed dc supply design provides an acceptable dc power source for testing distributed generation equipment under IEEE 1547 at not only relatively high power levels, but also light power levels.

Increasing load densities are leading to higher fault currents that may exceed the ratings of current circuit breakers. In addition, computer-controlled equipment is more susceptible to power supply disturbances of relatively long durations. So, there is a need for a new piece of equipment which is able to interrupt fault currents before reaching their first maximum peak isolating very fast faulted sections of a distribution system. Solid-state fault current limiters (SSFCL) have been proposed as a solution to accomplish the above, and thus, as a substitute for slow-operating electromechanical circuit breakers. The design of a silicon carbide fault current limiter with high voltage blocking capability and the subsequent testing at a 15-kV test facility are addressed in this paper. The semiconductor devices of this series-connected SSFCL are custom packaged silicon carbide super gate turnoff thyristors and SiC PIN diodes. The 4.16-kV experimental tests illustrate the performance of the proposed SSFCL and demonstrate the potential for deploying them in distribution systems.

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