Browsing by Author "Biswas, Suvankar"

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    Application of Integrated Magnetics and Discontinuous Conduction Mode to Multi-port DC-DC Power Conversion for integrating PV panels with storage
    (2016-12) Biswas, Suvankar
    Multi-port converter design and analysis presents one of the most intriguing challenges in the incorporation of renewables in the power grid. Choice of topology is of paramount importance to improve the power conditioning. To this eect, the Cuk topology can be a suitable candidate : low Electromagnetic Interference (EMI), low component count, simplied Maximum Power Point Tracking (MPPT) and power management, reduction of lter capacitor requirement, high eciency. This thesis revisits the concept of integrated magnetics in the Cuk topology and uses it judiciously to achieve the aforementioned requirements, by generating ripple-free currents at two terminals, independent regulation of two outputs in addition to magnetic integration. However, till date, no completely deterministic method has existed to design the integrated magnetic version of the Cuk converter. Two dierent methods, adopted from the area-product and the Kg (geometrical constant) methods are explored to design the two-port version of this converter. The area-product method is validated by means of experimental results on a 250W prototype. The ideas are then extended to a three-port version, but with the addition of another feature: independent regulation of two output ports. This is achieved by means of a combined Continuous Conduction Mode (CCM)-Discontinuous Conduction Mode (DCM) operation, but without sacrificing the ripple-free nature of currents on two of the ports. The non-isolated version of this converter, meant for modular use in a microconverter architecture, is validated by means of simulation and experimental results on a 150W prototype. A soft-switching scheme has also been demonstrated for a three-port converter with integrated magnetics. This has an active-clamp Zero-Voltage Switching (ZVS) turn-on circuit with the addition of a Zero-Current Switching (ZCS) turn-o. The design of the external components and simulation results for the same are presented as well. Finally, with the ever-increasing adoption of wide bandgap devices and planar magnetics in power electronics, it makes sense to get rid of the isolation transformer altogether for PV-to-grid applications, since isolation is not an imposed standard in PV power systems. Two Cuk converter based topologies are proposed which are hybrid charge-pump/inductive converter circuits. Simulation results are presented for the same.
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    Multiport DC-DC conversion incorporating integrated magnetics for renewables
    (2014-03) Biswas, Suvankar
    Multi-port converter design and analysis presents one of the most intriguing challenges in the incorporation of renewables in the power grid. Choice of topology is of paramount importance to improve the power conditioning. To this effect, the integrated Cuk topology achieves multiple objectives : low EMI, low component count, simplified MPPT tracking and power management, reduction of filter capacitor requirement, high efficiency. This is achieved by integrating all the magnetic components on a single core, and addition of soft-switching capability thereof. This thesis revisits the concept of integrated magnetics and formulates an elegant solution procedure to the problem of zero-ripple. It investigates the idea of utilizing the concept of a coupled-inductor filter on a three-port converter and removes the need for an external filter, thereby almost introducing an effective DC-DC transformer. The pre-FEM(finite element modelling) selection and design of the core and circuit aspects have been explained in this thesis. The simulation results are presented using PLECS. Additionally, some FEM results are added for the reduced three-winding structure. The validation of some design parameters are also discussed.A soft-switching scheme has also been demonstrated for a two-port converter with integrated magnetics. This has an active-clamp ZVS turn-on circuit with the addition of a ZCS turn-off. The design of the external components and simulation results for the same are presented as well.