High Gain Transformer-less DC/AC Inverter for PV System

Investigation interests on many scientific aspects of photovoltaic (PV) trans-former-less inverter system has improved over the past decade. Using step-up transformer or high frequency transformer in electrical system has made the entire system expensive and voluminous. There is alternative topology to replace the transformer by implementing DC/DC quadratic boost converter to expand the voltage from 12VDC to 325VDC from the photovoltaic (PV) solar and convert it to AC applying H-bridge inverter circuit. This method will replace the conventional method of bulky transformer into a lighter converter with the same performance. The circuit is simulated using Power Sim (PSIM) software to initiate the design and study the circuit capability. The experimental result will project the exact voltage in the range of 230VACrms . The harmonic profile of the inverter is studies and compared with the normal inverter configuration.

Development of square wave inverter using DC/DC boost converter

<span lang="EN-US">This paper proposes an alternative topology of an inverter to the existing topologies available in the market. A prototype is intended with the purpose of investigates the possibility of designing an inverter using two Boost Converters. This project initialized with a series of simulations using Matlab in order to determine the feasibility of the proposed topology. The next step is the design and development of the proposed prototype where suitable electronics components are chosen based on the simulation result. A PIC microcontroller is used to control the proposed prototype where a control scheme is created based on the programming in the microcontroller. The performance of the proposed prototype has been verified to be optimum by several practical testing using different values of capacitor, inductor and duty cycle. Lastly, data and analysis are presented in a proper mannered way. In the end, this project intends to produce stepped-up square wave output voltage waveform by proper controlling of two Boost Converters.</span>

Development of square wave inverter using DC/DC boost converter

<span lang="EN-US">This paper proposes an alternative topology of an inverter to the existing topologies available in the market. A prototype is intended with the purpose of investigates the possibility of designing an inverter using two Boost Converters. This project initialized with a series of simulations using Matlab in order to determine the feasibility of the proposed topology. The next step is the design and development of the proposed prototype where suitable electronics components are chosen based on the simulation result. A PIC microcontroller is used to control the proposed prototype where a control scheme is created based on the programming in the microcontroller. The performance of the proposed prototype has been verified to be optimum by several practical testing using different values of capacitor, inductor and duty cycle. Lastly, data and analysis are presented in a proper mannered way. In the end, this project intends to produce stepped-up square wave output voltage waveform by proper controlling of two Boost Converters.</span>

Ingroup relationships of Lagerpetidae (Avemetatarsalia: Dinosauromorpha): a further phylogenetic investigation on the understanding of dinosaur relatives

Despite representing a key-taxon in dinosauromorph phylogeny, Lagerpertidae is one of the most obscure and enigmatic branches from the stem that leads to the dinosaurs. Recent new findings have greatly increased our knowledge about lagerpetids, but no phylogenetic analysis has so far included all known members of this group. Here, we present the most inclusive phylogenetic study so far conducted for Lagerpetidae. Phylogenetic analyses were performed based on three independent data matrixes. In two of them, Lagerpeton chanarensis Romer, 1971 is the sister taxon to all other known Lagerpetidae, whereas Ixalerpeton polesinensis Cabreira et al., 2016 is in a sister group relationship with a clade that includes PVSJ 883 and Dromomeron. Conversely, the other analysis supports an alternative topology, where I. polesinensis is the sister taxon to either L. chanarensis or all other Lagerpetidae. Although coeval and geographically close, I. polesinensis and PVSJ 883 do not form a clade exclusive of other lagerpetids. As previously suggested D. gigas Martínez, Apaldetti, Correa & Abelín, 2016 is the sister taxon of D. romeri Irmis et al., 2007. The phylogenetic analyses also indicate that the earliest lagerpetids are restricted to southwestern Pangea, whereas later forms spread across the entire western portion of the supercontinent. Finally, quantification of the codified characters of our analysis reveals that Lagerpetidae is one of the poorest known among the Triassic dinosauromorph groups in terms of their anatomy, so that new discoveries of more complete specimens are awaited to establish a more robust phylogeny.

Analysis of Integrated Current Sense in Multiphase Buck Converters

Accurate and lossless current sensing is vital for high performance multiphase buck converters used in the latest voltage regulation modules (VRMs). A synchronous FET onstate resistance based approach is an alternative topology to DCR based sensing and is compatible with any controller, which requires inductor current information. The MOSFET driver has built-in sense circuitry, which when co-packaged with the MOSFETs reduces total footprint and ease of design. The Powerstage embodiment virtually eliminates the parasitic inductance and resistance between Control and Synchronous power MOSFETS; and using thick copper clips substantially reduce the parasitics associated with the input supply voltage (VIN) and the switch node output voltage (VSW) connections when compared to wire-bonded solutions. This paper presents a novel investigation into a contradictory low on-resistance paradox in a stacked 3D configuration. Through analysis, characterization and simulation the author deciphered the conundrum leading to a root cause explained by a mismatch of internal gain and referenced on-resistance. Building on previous metrology improvements the innovative insights drove analysis toward root-cause.