SVM based control of a single-phase half bridge boost rectifier under power factor correction and balanced operation

Abstract

A vector control based single-phase half-bridge boost converter circuit operating at a fixed high switching frequency is proposed in order to obtain a unity power factor (PF) and a balanced operation of the DC-link capacitors. In most cases this structure is controlled via a hysteresis comparator and a current sensor. Moreover, to prevent any imbalance in the voltages of the two DC-link capacitors it is necessary to use an additional voltage feedback. In the present paper a PWM switching technique which takes account of the phasorial nature of several electrical magnitudes in the converter is utilized. A mathematical model of the boost rectifier in the direct and quadrature axes is described and it is shown that this system is unstable and presents two control inputs. Then, to provide stability to the converter and to obtain the desired output DC voltage with a unity PF (though it can be set to another value) and voltage balance in the DC-link capacitors two feedback loops are implemented through both inputs. Analytical results are verified through simulation of the averaged circuit model. An experimental prototype is being made which will work from 90 V peak at the input to 300 V DC at the output.