Conversor CC-CC AGT-CCTE com controle de balanceamento de corrente no transformador

Abstract

The work presents the study of a control technique that balances the currents in the transformer primary windings of the converter CC-CC AGT-CCTE in order to prevent such element from saturating. For this converter, proposed by Araújo et al. (2010), all its components were dimensioned considering a duty cycle (D) of 0.7, minimum input voltage of 42 V and operation in MCC. To verify the accuracy of the calculations, open-loop simulations of the power circuit were performed, which showed compliance with theoretical values. The development of the control circuit design was also presented and it is composed by the main current loop, voltage loop and current balance loops, in which the latter allows balancing the currents in the primary windings of the converter transformer. The main current and voltage loops make it possible to regulate input current and output voltage, respectively. To validate the effectiveness of the control circuit, simulations were carried out with and without the current balance loop, both in steady state and in dynamic state, using linear and non-linear load. Tests with ideal parameters and with a difference of up to 10% in the amplitude of the triangular carriers were successful in balancing the currents that pass through the primary windings of the transformer. However, with a difference of up to 10% in the frequency of the carriers, no advantages were observed in the use of current balance meshes, since with any frequency variation of the carriers the necessary 180-degree phase shift is lost.