Filter Optimization for multi-phase DC-DC converter in automotive energy backup system

Abstract

Cascaded filters offer a possibility to minimize the size of the filter components due to their increased attenuation at high frequencies. A cost optimized design of a cascaded filter of a multi-phase converter for an automotive energy back-up system will be shown, that results in small values of the inductances. However, the decreasing inductance values results in increasing current ripples in the first filter stage. The implementation of coupled inductors helps to reduce the current ripples of the single phase currents significantly and achieves a cost optimized design with increased converter efficiency. The influence of tolerances on the ripple cancelation phenomenon in multi-phase converters and coupled inductors on the cascaded filter design will be analyzed. The theoretical predictions are in good correlation with the experimental results obtained from a full-size prototype converter.

Comparison of multi-port converter topologies with bidirectional energy flow for automotive energy net applications

“…By using phase-shifted pulse-width modulation of the different converter phases the high frequency ripple currents in the three ports of the converter can be reduced. Furthermore by coupling the inductors of the different phases the size, weight and costs of the inductors can be reduced [13,14].…”

Coupled-Inductor Filter: A Basic Filter Building Block

“…It is critical then that the value of k √ (L dc /L ac ) not be too close to unity, or the notch frequency will be extremely sensitive to changes in k, L dc , and L ac . On the other hand, k √ (L dc /L ac ) should be close to unity for good attenuation of frequencies above ω notch , following from the asymptotic HF gain given in (3). In a practical design, a compromise is required.…”

Optimal peak‐efficiency control of the CMOS interleaved multi‐phase step‐down DC‐DC Converter with segmented power stage

“…On this account, term ½ in (9) disappears. Equalling (9) and (10) then results in the energy balance (11) This allows to obtain the value of I B , which is to be integrated by capacitor C matched to C GS(N)…”

“…This results in considerable reduction of the electro-magnetic interferences [6][7][8]. Consequent reduction of the passive component size (input and output filters) enables a compact flat-package realisation, suitable for portable device applications [9]. Typical architecture of the multi-phase converter with highlighted input and output currents I IN and I OUT is shown in Fig.…”

“…In these figures, a decrease (and for some particular values cancellation) of AC ripple currents can be seen. Moreover, it appears that fundamental frequency of all AC components is n-time higher for the multi-phase converter, when compared with its single-phase counterpart [7][8][9]. Alternatively, further reduction of the residual AC ripple current/voltages are described in the literature, as for instance method based on active ripple cancellation [10], or interleaved converters with coupled inductors [11].…”