Download analysis of the interleaved isolated boost

ANALYSIS OF THE INTERLEAVED ISOLATED BOOST
CONVERTER WITH COUPLED INDUCTORS
ABSTRACT:
This paper analyzes the interleaved boost with coupled inductors (IBCI) converter, which
is an isolated topology that is suitable for high step-up applications. Two main contributions are
given: an exhaustive steady-state analysis and an accurate small-signal model. The former allows
for deriving a closed-form no iterative design procedure for the power-stage active and passive
components. In addition, it reveals an interesting equivalence with an apparently different
converter, i.e., the single active bridge. Subsequently, the IBCI converter dynamic behavior is
investigated, deriving a nonlinear average model that, under small-signal approximation, can be
linear zed around a given operating point and used for feedback controller design. A single
photovoltaic module interface converter, rated for 300-W output power, is considered as a case
study to validate the analysis outcome and the design procedure. Both are fully validated by
measurements taken on the laboratory prototype.
INTRODUCTION:
A configuration with many parallel-connected boost-fly back converters sharing a single active
clamp has been proposed, which requires n + 1 magnetic elements, where n is the phase number.
A bidirectional boost coupled with a fly back stage has been proposed, giving rise to a non
isolated structure, where soft-switching is achieved at the expense of a high circulating current.
A family of isolated converters providing a continuous input current is described, where two
isolated fly back converters, including cross-coupled windings and a single active clamp, are
used. These topologies require two transformers with three windings each.
A cascaded boost and isolated half-bridge stages sharing the same switching cell are described,
in which the total power is processed twice. An interleaved boost with series-connected outputs
is presented, which is able to achieve input current ripple cancelation at a predetermined dutycycle value.
A double dual boost has been analyzed, with the focus on small-signal modeling and control
design. An isolated converter with an interleaved current source generator employing a resonant
tank for zero-current commutation is proposed.
A voltage doubler rectifier is also used to increase the voltage gain. However, operation at dutycycle values below 50%, i.e., in a non overlapping mode, is not possible, unless suitable
provisions are taken to limit the device overvoltage when both switches are open.
EXISTING SYSTEM:
Conventional step-up converters, such as the boost converter and flyback converter,
cannot achieve a high step-up conversion with high efficiency because of the resistances of
elements or leakage inductance; also, the voltage stresses are large. A boost converter (step-up
converter) is a DC-to-DC power converter with an output voltage greater than its input voltage. It
is a class of switched-mode power supply (SMPS) containing at least two semiconductors (a
diode and a transistor) and at least one energy storage element, a capacitor, inductor, or the two
in combination. Filters made of capacitors (sometimes in combination with inductors) are
normally added to the output of the converter to reduce output voltage ripple.
PROPOSED SYSTEM:
Continuous input current can also be obtained using an interleaved boost input stage, for
the non isolated version, and for the isolated version herein called interleaved boost with coupled
inductors (IBCI). Similar interleaved topologies are described, where the two coupled inductors
are replaced by one or two inductors and a transformer. In addition, the value of the output
capacitors is reduced, so as to exploit the resonance between them and the secondary side
inductor L, thus changing some commutations from zero voltage to zero-current type.
ADVANTAGES:

continuous input current, due to ripple cancelation

inherent current sharing

reduced switch voltage stress

zero-voltage commutations in a wide load range

leakage inductance exploitation

clean device voltages without ringing
BLOCK DIAGRAM:
TOOLS AND SOFTWARE USED:

MPLAB – microcontroller programming.

ORCAD – circuit layout.

MATLAB/Simulink – Simulation
APPLICATIONS:

fuel cells (FCs)

single photovoltaic (PV) modules
CONCLUSION:
In this paper, a detailed steady-state analysis of the IBCI has been presented. This
allowed the definition of a noniterative design procedure where all circuit parameters can be
sized moving from a reduced set of specifications. Incidentally, the structural equivalence of the
IBCI and the SAB has been illustrated. A nonlinear average model and a linear small-signal
model were also derived, which allow for accurately predicting the IBCI c onverter dynamic
behavior. The model revealed how the converter response is dominated by the boost input stage
and by the output filter time constant, at least up to one tenth of the switching frequency. The
effect of the energy transfer inductor and of interleaving operation is therefore negligible in that
range. The design procedure has been applied to design a case study, a 300-W-rated prototype,
suitable as a PV module front-end converter. Nevertheless, the interleaved operation, together
with the continuous input current absorption, makes this topology suitable for higher power
levels as well. Examples in the kilowatt range are indeed reported in [22] and [23]. The prototype
has been extensively tested, and the experiments have proven the accuracy of the steady-state
analysis of the design procedure as well as of the small-signal model. The converter has shown a
95.8% peak efficiency when operating at 26-V input and delivering 300-W output power at 400
V.
REFERENCES:
[1] R. J.Wai and R. Y. Duan, “High step-up converter with coupled-inductor,” IEEE Trans.
Power Electron., vol. 20, no. 5, pp. 1025–1035, Sep. 2005.
[2] J. W. Baek, M. H. Ryoo, T. J. Kim, D. W. Yoo, and J. S. Kim, “High boost converter using
voltage multiplier,” in Proc. IEEE IECON, 2005, pp. 567–572.
[3] G. Spiazzi, P. Mattavelli, and A. Costabeber, “Effect of parasitic components in the
integrated boost-flyback high step-up converter,” in Proc. IEEE IECON, 2009, pp. 420–425.
[4] G. Spiazzi, P. Mattavelli, and A. Costabeber, “Improved integrated boost-flyback high stepup converter,” in Proc. IEEE ICIT, 2010, pp. 1169–1174.
[5] M. Das and V. Agarwal, “A novel, high efficiency, high gain, front end dc–dc converter for
low input voltage solar photovoltaic applications,” in Proc. IEEE IECON, 2012, pp. 5744–5749.