Keywords: single ended primary inductance converter, SEPIC, switching function modelling, power factor correction, PFC, single–phase rectifiers, feedback control, experimental validation, hysteresis, source current THD, total harmonic distortion, voltage regulation
Modelling, design and control of a SEPIC power factor corrector for single–phase rectifiers: experimental validation
In this paper, a new general case switching–function–based model is proposed for a DC–to–DC single ended primary inductance converter (SEPIC). Compared to conventional buck or boost converters, this topology allows a low current ripple at the input for a relatively low level of the DC–bus voltage. The converter is used as a power factor correction (PFC) circuit for a single–phase rectifier and, based on the obtained model, steady–state analysis is performed and new design criteria were established for a proper selection of the inductors and capacitors. In order to verify the performance of the converter in PFC applications, a simple hysteretic–based feedback control is implemented and verified through simulations. For validation purpose, experiments are carried out on a 1kW laboratory prototype of the converter. The system performance is evaluated in terms of source current total harmonic distortion (THD), voltage regulation, robustness and dynamic behaviour.