Buck converter digitally controlled by a fuzzy state-space controller

In this paper a digitally controlled step down converter using fuzzy state space controller is studied. The state controller is designed to eliminate the start-up overshoot and reduce maximal dynamic error of load change response, but the state controller is not capable to eliminate the steady-state error under the load change condition. In order to improve this property, two control algorithms were investigated. The first one was the state controller with constant gains supported by an additional decomposed fuzzy PID controller and the second one was a fuzzy state space controller. Both of control algorithms are performed at a continuous current mode of operation. The experimental results are presented in the paper. The control algorithms are implemented on 16-bit DSP unit. All algorithm are suitable for implementation by FPGA as well.