The application of posicast control to DC-DC converters

Analysis, design and simulation of a Posicast-based controller are presented for both buck and boost converters. Posicast is a feedforward compensator, which eliminates the overshoot in the step response of lightly damped systems. However, the traditional method is sensitive to variations in natural frequency. The new method described here reduces this undesirable sensitivity by using Posicast within the feedback loop. Design of the Posicast function is independent of computational delay. Compared to a PID controller, the new controller results in a lower noise in the control signal. Furthermore, for the boost converter, the unfavorable effect on system stability caused by RHP zero of the model can be neglected in the design of controller. The performance of Posicast-based controllers for both buck and boost converters has been investigated through simulations using SIMULINK.