Sliding mode control of the DC-DC flyback converter with zero steady-state error

In this paper a novel approach for controlling the output voltage of the isolated flyback converter is presented using sliding mode controller. Due to non-minimum-phase nature of the converter and presence of a right-half-plan-zero in voltage transfer function, indirect regulation of the output voltage is applied. In the designed controller, simultaneous use of output voltage and transformer current feedbacks improves dynamic response of the controller. The sliding mode controller is developed so that in the final control law, integral of the output voltage error is present and consequently the output voltage error will be zero in the steady-state. Also, in order to measure transformer magnetizing current, simple and efficient method is proposed. Finally, in order to evaluate response of the controller, flyback converter is a simulated using MATLAB / Simulink.