Abstarct: In this work a method is proposed in order to control of DC-DC boost converter output voltage. Model baxsed Fractional-supervisory control method is utilized such that the linear model corresponding to every operating point and Fractional order PID coefficients are calculated in order to achieve this aim. The reference voltage determines these coefficients. Then a Petri Net type supervisor is neaded to generate coefficients of The Fractional Order PID controller corresponding to every operating point. Finnaly analytical results are simulated in Matlab Simulixnk invironment and accuracy of calculations are illustrated.