Evolution and Control of Dual-Input Bi-directional Port Boost DC–DC Converter for Battery Storage Based DC Systems

This article proposes a topological evolution of dual-input single-output dc–dc converter for battery-based dc system. Three sixth-order dual-input boost converters (SODIBC Type-1 to Type-3) have been evolved. Among these, SODIBC Type-3 is identified as the best topology due to its salient feature, which are: high voltage conversion ratio and bi-directional port without increasing the number of controlled switches. It is formulated using a combination of conventional boost and a modified buck–boost converter. An additional switch is inserted to interconnect the battery to the bi-directional port, which also controls the charging and discharging current. The presence of inductor at the input side keeps its source current ripple within the prescribed limits. Also, both the inputs share a common ground with the output, which reduces the electromagnetic interference in the system. This double input single output converter is embedded with multimode operation (Type-A, Type-B, and Type-C) and its mode transition is through simple switch gate control. The power conversion and control features are investigated by transforming it into a two-input two-output multivariable control problem. Through small-signal analysis, the SODIBC transfer function matrix model is formulated. On the basis of this, a multivariable diagonal controller is designed for battery discharging operation by enforcing the gain margin and phase margin specifications. These are ensured here by shaping the Gershgorin bands, which are due to the interaction indicating off-diagonal transfer functions of the plant transfer function matrix. The mathematical modeling of the topologies and comparison analysis has been carried out. Finally, a 100 W SODIBC prototype has been developed to confirm the effectiveness of battery bi-directional power transfer capability and the designed multivariable control strategy.