Improving current equalization in energy storage systems for lighting smart grids applications with the bidirectional one-leg converter

摘要

This paper studies the limitations of the control strategy of a bidirectional one-leg converter able to move energy from a low-voltage DC bus to a battery bank or an ultra-capacitors bank and vice-versa. One of the goals of the work is to implement strategies which allows parallel operation of these modules without communication between them. The power converter was modeled in order to carry out a proper digital current controller. This way, the control of the extracted or injected current into the DC bus can be done either by means of a classic master-slave parallelizing technique or by the proposed strategy in this work: a bus current control as a function of the voltage of the DC bus (Current Droop strategy). The design has been validated theoretically and experimentally over a DC bus with a nominal value of 48 volts over an experimental workbench (eWRE project).