Analysis and stabilization of CCM flyback converters supplying constant power loads

This paper proposes a control scheme for stabilization and voltage regulation of a continuous conduction mode (CCM) flyback converter supplying constant power loads (CPL)s. A two-stage controller is proposed for the non-linear system. The first stage involves inserting a virtual resistor in series with the primary winding of the flyback transformer. The virtual resistance, inserted through control action damps limit cycle oscillations due to CPL. This stage is referred to as active damping stage. The second stage enables voltage restoration and performs voltage regulation in the event of source and load variations. This stage is referred to as voltage compensation stage. Stability conditions are derived for equilibrium points. A method to choose one of the control parameters to minimize the output capacitance of the converter is proposed. Simulation results are presented using both averaged and switched models to verify the proposed control scheme.