help me on building buck-boost converter to control dc motor plz

Abstract

This paper presents a Buck-Boost converter using a MOSFET as a switch fed a dc series motor. The characteristics for step - up and down of the output voltage are studied. It is found that this system posses a good operation performance with a minimum ripple in the output of the motor current and voltage. The mathematical models describing both the open and closed-loop systems are proposed using the differential equations describing the system in different modes of operation for open and closed loop systems. The steady-state, starting-up and transient operating conditions are investigated for the open loop system. For the closed loop system, a positive step change in the load is investigated. Also, the effect of positive and negative step changes in the reference voltage are studied.