Identification and Robust Control of DC/DC Converter Hammerstein Model

This paper deals with model-based robust control of dc/dc power electronic converters. The converter is described by means of a Hammerstein model consisting of the nonlinear static characteristics of the converter and a linear time-invariant (LTI) uncertain model whose parameters depend on the actual duty-cycle operating range. This suggests that the controller be designed using robust control techniques. In view of applying robust control, identification of the earlier LTI models is performed by means of simulation experiments, carried out on a converter switching model implemented on MATLAB/SIMULINK environment. Internal model control (IMC) structure is employed for the controller design, but its implementation is performed using the equivalent feedback control structure. Comparison with some controllers designed starting from models that do not require identification steps is performed with the aim of showing the advantages connected to the availability of a suitable model, which describes the essential aspects of the behavior of the system, for control purposes. Comparison with a PI controller designed by means of phase margin assignment is carried out with the aim of justifying the use of more sophisticated control methods. Experimental results are also shown that aimed to prove the validity of the whole approach. Comparison of experimental and simulation results is also performed.