Zeta converter operating in continuous conduction mode using the unity power factor technique

Several topologies have been researched in search of a structure which not only is able to fulfil the requirements of the power factor and the amount of harmonics injected in a line foreseen in the norms, but which would also show the best ensemble of characteristics. Although being the most frequently employed and studied structure, the boost converter presents some limitations in its application, for it is not a naturally isolated structure and because it only operates as step up voltage. As an alternative to these limitations the Zeta converter operating in discontinuous mode applied to the power factor correction was proposed (D.C. Martins, 1994). The Zeta converter showed itself as very attractive because it operates as step up as well as step down voltage, beside the fact of being a naturally isolated structure and processing power at one single stage. But in applications which imply high power, the operation of a converter in discontinuous mode is not attractive because it results in high RMS values of the currents causing high levels of stress in the semiconductors. Aiming to extend the alternative by use of the Zeta converter in power factor correction to applications in higher powers, and having in mind the main characteristics and advantage of this converter in face of the limitations of the boost converter, this paper presents the study of the Zeta converter operating in continuous conduction mode for power factor correction by using the average current mode control.