Analysis of Operating Modes of a Bidirectional Quasiresonant DC Voltage Converter as Employed in Energy Storage Systems

The paper is dedicated to a voltage converter based on symmetrical inverter topology and suitable for power flow reversal. The current applications of the device under consideration include electric power storage and backup systems with the possibility of subsequent energy return to the electric power grid or the consuming load. Converters of this type in conjunction with other bidirectional converters can be used to convert direct current to both direct and alternating current. The implementation of the quasi-resonant process of transistor switching for both voltage boosting and bucking minimises the dynamic switching loss. Preferred ranges of electrical parameters have been determined for the oscillating circuit and the high-frequency transformer, which ensure safe output voltage regulation in a wide range. Wide-range regulation requires more complex circuitry, which reduces the efficiency and reliability of the device due to the increased number of semiconductor elements. For regulation and small deviation of input voltage, the proposed solution is the optimal choice.