dc.contributor.advisor | Basu, Kaushik | |
dc.contributor.author | Rawat, Shubham | |
dc.date.accessioned | 2022-10-13T04:46:08Z | |
dc.date.available | 2022-10-13T04:46:08Z | |
dc.date.submitted | 2022 | |
dc.identifier.uri | https://etd.iisc.ac.in/handle/2005/5874 | |
dc.description.abstract | The development of Wide Bandgap (WBG) devices has enabled power electronic converters
to operate at much higher frequencies, voltages and high power. Working at a higher
switching frequency minimises the size of magnetics but results in significant switching
losses and electromagnetic interference (EMI) noise. Thus, it necessitates the use of soft-switching
techniques to reduce these losses. Phase-Shifted Full-Bridge (PSFB) Converter
is the most widely used soft-switching topology in the high-voltage and high-power, unidirectional,
DC-DC conversion. The phase shift PWM control utilises the converter parasitics
to achieve zero voltage switching (ZVS) turn ON. The gating technique allows the
magnetic energy stored in the leakage inductance of the isolation transformer to charge
and discharge the output capacitances of the inverter leg. However, the converter suffers
from severe voltage overshoots across the rectifier bridge during the zero to the active state
transition. The resonant circuit formed between the transformer leakage inductance and
the parasitic diode capacitance of the rectifier is responsible for the high-voltage ringing.
Many passive and active snubbers are presented in the literature to mitigate the high-voltage
overshoots across the diode bridge. While passive snubbers are relatively simple
to implement than active snubbers, they are lossy. On the other hand, the active snubbers
require additional gate driver circuitry and complex control.
The first part of the thesis proposes a novel passive regenerative snubber to overcome
the mentioned drawbacks of the existing snubbers. The proposed snubber is ideally lossless
with no control complexity. The work covers a detailed analysis of the PSFB operation
with the proposed snubber while obtaining closed-form expressions for the converter state
variables at the end of each topological stage. The study considers all the major converter
parasitics, such as transformer leakage and magnetising inductances, and parasitic capacitances
of the converter. Given the new snubber, the thesis also lays out a step-by-step
PSFB design procedure utilising the analysis carried out in the first part of the work. The
design aimed to develop a 100 kHz PSFB for an input voltage of 360-440 V in the output
power range of 0.5-1.5 kW at a fixed output voltage of 48 V. The design approach focuses
on two design objectives - All inverter switches must achieve ZVS turn ON and the
desired converter gain for all possible operating conditions.
A hardware prototype is built and tested. The experimental results validate the effectiveness
of the snubber in reducing the voltage overshoot. Further, the analysis and design
accuracy is verified using the measured state variables. The work, at last, presents the
overall converter efficiency and the loss distribution among the converter components. | en_US |
dc.language.iso | en_US | en_US |
dc.rights | I grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part
of this thesis or dissertation | en_US |
dc.subject | Isolated Unidirectional Converters | en_US |
dc.subject | Passive Snubbers | en_US |
dc.subject | Regenerative Snubbers | en_US |
dc.subject | Phase Shifted Full Bridge | en_US |
dc.subject | Voltage Overshoot | en_US |
dc.subject.classification | Research Subject Categories::TECHNOLOGY::Electrical engineering, electronics and photonics::Electric power engineering | en_US |
dc.title | A Novel Passive Regenerative Snubber for the Phase-Shifted Full-Bridge Converter: Analysis, Design and Experimental Verification | en_US |
dc.type | Thesis | en_US |
dc.degree.name | MTech (Res) | en_US |
dc.degree.level | Masters | en_US |
dc.degree.grantor | Indian Institute of Science | en_US |
dc.degree.discipline | Engineering | en_US |