| Abstract |
This paper proposes a two-level cascaded control strategy for a DC-DC-Katium-power-converter-based battery charger for railway applications. The Katium converter represents a particular DC-DC power converter topology, which is employed in the considered application as a Li-ion battery charger and a low-voltage power supply for a load composed of a resistive part and a constant-power part. The system model has a bilinear nature. A control-oriented modelling leads to obtaining a family of linear parameter-varying models by linearization around successive operating points, which mainly depend on the load power to be supplied. The battery current regulation is a disturbance-rejection problem, involving both constant and periodic (sinusoidal) disturbances. This problem is here solved by means of a two-level cascaded control structure whose lower level relies upon a pole-placement-based control on the previously derived state-space linear parameter-varying model, enriched with both usual integrators - for constant disturbance rejection - and resonant integrators, ensuring sinusoidal disturbance rejection. MATLAB®/Simulink® is chosen as software environment for numerical simulation closed-loop validation. |
