Non-linear sampled-data model for fourth order boost DC-DC converter

In this paper a non-linear sampled data model for fourth order DC-DC converters is developed. This model closely depicts the effect of large-signal variation in duty ratio caused due to large-signal disturbances such as load/source transients, which linear small-signal models and other non-linear models generally fails to predict. Large-signal linearization is applied to the exact discrete-time model, which is the basis for the formulation of non-linear sampled-data model. The validity of the proposed model is demonstrated on a 28 V 30 W fourth-order boost DC-DC converter. The mathematical model is transformed into the Matlab-Simulink platform for better illustration during open and closed loop operation. Response of the model for load/source disturbances simulated in Matlab-Simulink is compared with the response from circuit simulation software PSIM. Simulation results are validated with the results obtained on the experimental prototype of the converter. Comparison of response shows that the proposed model accurately predicts the converter dynamics.