Transistor clamped five level inverter using non-inverting double reference single carrier PWM technique for photovoltaic applications

This treatise deals with transistor clamped five level inverter Using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique. Conventional or two level inverter have drawbacks like i) Requirement of fast switching devices ii) Very high dv/dt iii) High Electromagnetic Interferences (EMI) iv) Bulky filters v) Faster heating of switches and vi) Not suitable for high voltage applications. Multilevel Inverters (MLIs) are engaged to conquer the drawbacks of conventional two levels inverter. MLIs generate an AC voltage using small voltage steps obtained with the help of DC supplies or capacitor banks. To design the proposed five level inverter 5 numbers of power control switches and 8 diodes are required. The proposed inverter circuitry is investigated by using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique in terms of harmonics content in output waveform. Under-modulation (modulation Index =0.85), unity (modulation Index =1) and over-modulation (modulation Index =1.25) PWM signal is obtained to drive control switches. Simulation results will confirm the functionality, design and operation of the proposed MLI and NIDRSC PWM Techniqu

Non isolated and non-invertingcockcroft-walton multiplier based hybrid 2Nx interleaved boost converterfor renewable energy applications

Abstract: In this paper hybrid non isolated and noninvertingCockcroft- Walton multiplier based 2Nx InterleavedBoost converter (2Nx IBC) for renewable energy applications is presented. The presented hybrid boost converter topology is derived from non-invertingNx Multilevel Boost Converter (Nx MBC) and inverting Nx Multilevel Boost Converter (Nx MBC). In renewable energy applications, generated voltage needs to be stepped up with high conversion ratio using a DC-DC converter at voltage levels as per the application requirement. The advantages of the presentedtopology of interleaved converter are high voltage conversion ratio, reduce ripple, low voltage stress, non-inverting output voltage without utilizing the high duty cycle, coupled inductors and transformer. The main advantage of presented topology consists in increasing voltage gain by adding capacitor and diode into circuitry without disturbing the main circuit.Moreover, the presented topologyis compared with several recent non isolated high gainDC-DC converters. The proposed topology is simulated in MATLAB/SIMULATION andobtained results verify the validity of the design and operation of converter

Offshore Wind Energy Conversion System Connected to the Electric Grid: Modeling and Simulation

This paper is on modeling and simulation for an offshore wind system equipped with a semi-submersible floating platform, a wind turbine, a permanent magnet synchronous generator, a multiple point clamped four level or five level full-power converter, a submarine cable and a second order filter. The drive train is modeled by three mass model considering the resistant stiffness torque, structure and tower in deep water due to the moving surface elevation. The system control uses PWM by space vector modulation associated with sliding mode and proportional integral controllers. The electric energy is injected into the electric grid either by an alternated current link or by a direct current link. The model is intend to be a useful tool for unveil the behavior and performance of the offshore wind system, especially for the multiple point clamped full-power converter, under normal operation or under malfunctions

Reconfiguration of Multilevel Inverter with Trapezoidal Pulse Width Modulation

This paper presents different multi-carrier unipolar trapezoidal pulse width modulation strategies for a reduced switch asymmetrical multilevel inverter. The different strategies are phase disposition, alternative phase opposition and disposition, and carrier overlapping and variable frequency that involve triangular waves as carriers with a unipolar trapezoidal wave as a reference. The reduced switch, asymmetrical multilevel inverter operation was examined for generating the seven-level output voltage using Matlab/Simulink 2009b and the results were verified with a real-time laboratory-based experimental setup using a field-programmable gate array. Different parameter analyses, such as total harmonic distortion, fundamental root mean square voltage, and distortion factor, were analyzed with different modulation indices to investigate the performance of the selected topology. Unipolar trapezoidal pulse width modulation provides a higher root mean square voltage value.publishedVersio

Age influence on effectiveness of a novel 3-phytase in barley-wheat based diets for pigs from 12 to 108 kg under commercial conditions

[EN] The main objective of this study was to evaluate the influence of pig's age on the effectiveness of a new microbial 3-phytase, produced by Komagataella phaffii, under commercial conditions in barley-wheat based diets. Two experiments were conducted in weaned, growing and finishing pigs; firstly, to determine phytase efficacy on dry matter, organic matter, energy, protein and mineral (phosphorus, P and calcium, Ca) digestibility (n = 48; Experiment 1), and secondly, to evaluate the effect of phytase on growth performance and bone mineralization (n = 312; Experiment 2). In each experiment, three barley-wheat based diets were formulated following the recommendations for each animal age, of which two versions were manufactured, including 0 and 1000 phytase units (FTU)/kg of feed of the new 3-phytase to be tested. Results showed the new phytase had the potential to increase the digestibility of Ca and P (on av. + 0.05 and +0.06, respectively; P < 0.01), especially P digestibility in growing pigs (+0.10; P < 0.001), consequently decreasing P and Ca excretion. Digestible energy (DE) of the diet increased with the addition of phytase in weaned pigs (+0.69 MJ/kg of dry matter (DM); P < 0.001). Dietary inclusion of new 3-phytase enhanced average daily gain from 46 to 94 days of age (+0.07 kg/d; P < 0.05) and decreased feed conversion ratio from 46 to 154 days of age (on av. -0.13; P < 0.05), although no significant effect was observed from 154 to 185 days of age. Addition of the new 3-phytase also promoted bone mineralization, increasing the weight of the bones (+3.99 and +3.64 g of tibia at 95 days and metacarpus at 100 days of age, respectively; P < 0.05) and the ash, Ca and P content in these bones (e.g. + 0.46 and +0.33 g of P in tibia at 95 days and metacarpus at 100 days of age, respectively; P < 0.001). In conclusion, pig age affected the efficacy of a new 3-phytase on P and Ca digestibility both in weaned and growing diets and DE content of the weaned diets, which also resulted in improvements in growth, feed conversion and bone development until 154 days of age. These effects seem to be reduced during the finishing period, although the advantages of the new 3-phytase on bone mineralization were maintained until 185 days of age.We thank the technical staff at the experimental farms of the Research and Technology Animal Centre (CITA-IVIA), the Institute of Animal Science and Technology (Universitat Politècnica de Valencia) and Javier Gómez (Crianzas Campovivo) for expert technical assistance and experimental support.Cambra López, M.; Cerisuelo, A.; Ferrer, P.; Ródenas Martínez, L.; Aligué, R.; Moset, V.; Pascual Amorós, JJ. (2020). Age influence on effectiveness of a novel 3-phytase in barley-wheat based diets for pigs from 12 to 108 kg under commercial conditions. Animal Feed Science and Technology. 267:1-13. https://doi.org/10.1016/j.anifeedsci.2020.114549S113267Adeola, O., & Cowieson, A. J. (2011). BOARD-INVITED REVIEW: Opportunities and challenges in using exogenous enzymes to improve nonruminant animal production. 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Animal production for efficient phosphate utilization: from optimized feed to high efficiency livestock

Phosphorus (P) is an essential nutrient for livestock but its efficiency of utilization is below 40%, contributing to environmental issues. In this review, we summarize recent approaches to optimize P availability in livestock diets and improve its utilization efficiency. Phase feeding could potentially reduce P excretion by 20%. Addition of phytase enzymes to diets increased P availability from 42 to 95%. Low phytate transgenic plants and transgenic animals increased P availability by 14% and 52-99%, respectively. In practice, a combination of phase feeding and enzymes has the highest potential for P reduction but legislation and ethics implications will prevent using transgenic animals in the short term. Functional and nutritional genomics may provide tools to improve efficiency in the future

Simple synthesis of 32P-labelled inositol hexakisphosphates for study of phosphate transformations

In many soils inositol hexakisphosphate in its various forms is as abundant as inorganic phosphate. The organismal and geochemical processes that exchange phosphate between inositol hexakisphosphate and other pools of soil phosphate are poorly defined, as are the organisms and enzymes involved. We rationalized that simple enzymic synthesis of inositol hexakisphosphate labeled with 32P would greatly enable study of transformation of soil inositol phosphates when combined with robust HPLC separations of different inositol phosphates