Adaptive Control Algorithm for Two-Stage Integrated DC Transformer in DC Microgrid Applications

Abstract

This paper presents the Two-Stage integrated DC Transformer (TSDCT) for DC Micro-Grid (MG) applications based on the Adaptive Control Algorithm (ACA). The prevailing control methods and design constraints employed in the DC transformer (DCT) do not consider the influence of the circuit's structural elements with their parasitic components on its performance. Consequently, it devalues the control variables that fail to achieve indispensable control features in the DC micro-grid network. Therefore, the proposed ACA is employed in the TSDCT, which improves the performance of TSDCT in comparison to the other control techniques in the DC micro-grid network. The proposed ACA includes the effect of the resonant tank circuit's parameters and converter's structural elements. Thereby, it defines the design constraints that significantly improve the performance of TSDCT in terms of efficiency and a wide range of voltage regulation at different buses. The detailed modeling and analysis are carried out at each stage to describe the principle and evolution of critical components involved in the ACA. Further, the control to output transfer functions are determined towards the implementation of the proposed ACA in the TSDCT. As a result, it exhibits voltage regulation in a wide range, soft-switching operation, high control resolution, and better performance under different operating conditions. Finally, a 4 kW laboratory platform is built, and test results validate the performance of the proposed TSDCT based on the proposed ACA for DC micro-grid applications.