A zero-voltage switching control strategy for dual half-bridge cascaded three-level DC/DC converter with balanced capacitor voltages

Abstract

The input cap voltages are unbalanced under the conventional control strategy in a dual half-bridge cascaded three-level (TL) DC/DC converter, which would affect the high voltage stresses on the capacitors. This paper proposes a pulse-wide modulation (PWM) strategy with two working modes for the dual half-bridge cascaded TL DC/DC converter, which can realize the zero-voltage switching (ZVS). More significantly, a capacitor voltage balance control is proposed by alternating the two working modes of the proposed ZVS PWM strategy, which can eliminate the voltage unbalance on the four input capacitors. Therefore, the proposed control strategy can improve the s in: 1) reducing the switching losses and noises of the power switches; and 2) reducing the voltage stresses on the input capacitors. Finally, the simulation results are conducted to verify the proposed control strategy.

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

“…Although ZCS technique can significantly reduce the tail current of the IGBTs, the maximum switching frequency of the IGBTs limits the magnetic components and space-constrained design. The converters in [24][25][26][27][28][29][30] use two half bridges to form the TL structure. Although it can eliminate the circulating current, in the primary side auxiliary circuit is also added to limit the ringing of the In this paper, a novel TL DC/DC converter with wide ZVS range, reduced circulating current and low filter requirement is proposed.…”