Analysis of DC-DC volt-inverting Luo converter with reduced output voltage ripples operating in DCM

The electromagnetic processes in volt-inverting Luo converter in discontinuous conduction mode (DCM) were studied using the method of averaging in state space based on Lagrange theorems. With the help of this method, a mathematical model was obtained, which made it possible to develop analytical relations for calculating the processes in converter in the DCM mode. The ratios for average and ripple values of currents and voltages in the reactive elements of converter, as well as the corresponding ripple factors, were obtained. These ratios contribute to simplification of converter calculations and allow to realize necessary output parameters with a given limitation on the magnitude of output voltage ripples and storage inductor current ripples. Graphical dependences of output voltage ripple factor of converter were calculated to illustrate the conducted research. It is shown that compared to traditional topology of the buck-boost converter, the output filter in volt-inverting Luo converter allows to reduce the ripple coefficient of output voltage by a number of times proportional to product of values of inductance and capacitance of the filter, as well as of the commutation frequency square.