Interconnected state observers for series resonant converters

We are considering the problem of state observation in series resonant converters (SRC). This is a crucial issue in SRC output voltage control as the control model is nonlinear and involves nonphysical state variables, namely real and imaginary parts of complex electrical variables. An interconnected high gain observer is designed to get online estimates of these states. The observer is shown to be globally asymptotically stable. Simulation results estimation, the global stability of the observer is analytically treated using the lyapunov theory; finally we present numerical simulation to illustrate the performance of the suggested approach.