Efficiency optimization of an automotive multi-phase bi-directional DC-DC converter

Output ripple reduction of an automotive multi-phase bi-directional dc-dc converter

“…Details on the additional controllers that decide on the number of activated phases N (1) and implement an offset current control (3) can be found in [6].…”

“…The current waveform shows a negative offset current −I 0 at the beginning of the period that allows ZVS of all four switches because the antiparallel body diode is conducting at turn-on of a switch and the parasitic output capacitance C oss assists the turn-off process [2]. However, there is a degree of freedom in selecting the switching times t i and algorithms for an optimized control behavior and optimized efficiency are proposed in [2] and [6].…”

“…It is advantageous to operate only a certain number N out of N Σ converter phases of a multi-phase converter at the same time to improve efficiency in part load conditions [6]. Typically, for the N operated phases equally distributed phase shift angles ϕ n = 2π n−1 N are introduced.…”

“…9 with the ratio I 2,mod,m /I 2,mod,n . With this approach and the fact that the phases can be instantly turned on and off [6], the tolerance measurements can now be carried out during nominal operation at the same operating point U 1 , U 2 , I 2 . Thereto, the current I 2 is controlled and delivered by only a single phase activated at the same time.…”

Comparative evaluation of soft-switching concepts for bi-directional buck+boost dc-dc converters

“…Equation (14) is considered as an upper limit of the RMS current, which in a practical implementation of the CF-ZVS modulation and especially in the part load operation and for v ≈ 1 could be reduced further by optimization of the switching times t i [14].…”