The correct operation of a microgrid requires storage devices that avoid instability of the system. The central part of an energy storage system is the DC-DC converter which connects the ultracapacitor pack or the battery pack and a DC bus of an energy system. This paper presents the DC-DC converter design to control of an energy storage system based on supercapacitors but it can be also used for charging and discharging of accumulators. The converter for such application should have a good transient response performance to prevent voltage sags in micro-grid. In this paper development of 4-phase interleaved DC-DC converter with using of the inter-phase coupled inductors is analyzed to improve transient response. The steady state phase and output current ripple of the interleaving bidirectional DC-DC converter is analyzed. The prototype of the converter has been built. Some of the experimental results are presented in the paper.