A DC-DC converter topology with phase shift control and lossless snubbers for use in a 200 A battery charger working on 400 V mains

A battery charger for telecommunications is presented. This converter operates at a rectified three phase 400 V mains which supplies the DC-DC converter with 750 V DC. The paper describes the switching loss reduction when high voltage IGBTs operate in this promising DC-DC converter topology. There are measurements on a transistor in a chopper circuit to investigate the turn-off characteristic with a capacitor in parallel with the transistor. This test was done on a Toshiba IGBT-module. The selected capacitor was then used for the measurements on the DC-DC converter. The measurements on the DC-DC converter were done with both Toshiba and Siemens IGBT modules. The stresses on the components are decreased both compared to hard-switched and resonant types of converter.