On the Passivity-based Control for Multilevel Inverters

In this paper the problem of reducing the total harmonic distortion (THD) with fast transient response of buck-type multilevel power inverters is approached from a control point of view. The main contribution is the proposition of a control law that, considering a standard circuit topology driven by an also standard switching policy of the PWM type, solves the output voltage tracking control problem with remarkable THD low levels and very fast transient response. The proposed controller is designed exploiting the dissipation (passivity) properties of the (approximated) averaged model of the circuit while its evaluation is carried out in an experimental setting with the objective to examine its robustness properties with respect load uncertainty and dynamic transient response. The experiments were carried out considering both linear and nonlinear loads