Signal flow graph nonlinear modelling of interleaved converters

This paper presents a systematic development of a unified SFG model for an N-cell interleaved DC-DC converter system operating in continuous current m ode. From this SFG small, large-signal and steady-state models are develope d, which are useful to study the converter behaviour. Converter performance expressions like voltage gain, efficiency and other small-signal transfer functions are derived. A straightforward algorithm is developed to draw the unified SFG of an N-cell interleaved converter system without going into t he rigorous procedure. Development of a unified signal flow graph is explai ned for a 3-cell interleaved converter system. Derivation of large, small-s ignal and steady-state models from the unified SFG is demonstrated by consi dering a 2-cell interleaved converter system. A large-signal model is progr ammed in a TUTSIM simulator, and the large-signal responses against supply, load disturbances are predicted. Signal flow graph analysis results are va lidated with PSIM simulations. Experimental observations are provided to va lidate the SFG modelling method.