New control method of bidirectional isolated dc/dc converter

- Control system which can obtain output voltage much higher than winding ratio of transformer -

Abstract

A new control system of the bidirectional isolated dc/dc converter which can obtain the output voltage much higher than the turn ratio of the transformer, will be presented. The output terminals of two single phase bridge inverter A and B are connected through an isolated transformer, and the pulse width of the inverter of higher d.c. voltage is narrowed to make equal the fundamental a.c. voltage of both inverters. After doing so, to control the power flow, the phase angle between both inverters is controlled. To make explanation simple, the transformer turn ratio is supposed to be 1:1. The d.c. voltage of the INV-A is 100[V], and the d.c. voltage of the INV-B is 200[V]. In this case, to make the a.c. output voltage of both inverters same, the pulse width of the INV-A is 180 degree and the pulse width of INV-B is narrowed to 60 degree. By doing so, the power flow from the d.c. 100[V] source to the d.c.200[V] source can be realized.