The article presents the analysis of the simulation test results for three variants of the power electronics used as interface between the power network and superconducting magnetic energy storage (SMES) with the following parameters: power of 250 kW, current of 500 A DC and voltage of 500 V DC. Three interface topologies were analyzed: two-level AC-DC and DC-DC converters; three-level systems and mixed systems combining a three-level active rectifier and a two-level DC-DC converter. The following criteria were considered: input and output current and voltage distortions, determined as THDi and THDu, power losses in power electronics components; cost of the semiconductor components for each topology and total cost of the interface. Results of the analysis showed that for high-power low-voltage and high-current power electronics systems, the most advantageous solution from a technical and economical perspective is a two-level interface configuration in relation to both AC-DC and DC-DC converters.