A series-connected asymmetrical PWM half-bridge three-level converter with reduced circulating current

[摘要] A novel three-level (TL) converter topology is proposed in this paper. The primary side of the proposed converter consists of two asymmetric half-bridge inverters, which are connected in series. The rectifier stage is composed of two parallel full-bridge-rectifier (FBR) which use the same diodes as the common current path. The asymmetrical-PWM control is employed to regulate output voltage. Compared with the traditional TL converters, the circulating current can be significantly reduced. Moreover, all the switches can achieve ZVS performance with a small leakage inductor over wide load range. The parallel connection of the two FBR also helps to reduce the current ripple of the filter inductor, leading to high density switching converter design. In this paper, a laboratory prototype (480-600Vdc input, 96Vdc/12A output) based on the proposed converter is built to validate the theoretical analysis.

[学科分类] 电子、光学、磁材料

[关键词] three level;zero-voltage-switching;circulating current;reduced filter size