Nonlinear control of a magnetic coupling converter for a supercapacitor storage device for a DC link stabilization

This paper presents a new control strategy for dc-link stabilization that use supercapacitors (SC) as the energy storage unit. A three-port isolated converter based on a dual active bridge topology is presented, and a reduced-order mathematical model of the system is described for power plant control. Using a nonlinear control approach based on the flatness property, we propose a simple solution to dynamic and stabilization problems in the power electronics systems. The controller design parameters are independent of the operating point at which interactions between the dc main substation, loads and energy storage unit are taken into account by the controller. Furthermore, high dynamics in the disturbance rejection are achieved, which is the key contribution described in this paper. To validate the proposed method, a hardware system is modeled using digital estimation with a DS1103 dSPACE controller platform. We analyze a prototype small-scale network that uses a 1 kW six-pulse rectifier as a dc substation and a 250 F, 32 V supercapacitor bank (by Maxwell Technologies Inc.) as an energy storage substation. Finally, the utility of the control algorithm is validated using experimental results measured during load cycles.