High-Accuracy Generalized Average Model of Dual Active Bridge Converters

This article presents a detailed procedure for deriving the generalized average model (GAM) of a dual active bridge converter. The proposed model incorporates higher orders of harmonic components to increase accuracy. Moreover, the turn ratio of the high-frequency transformer (N_t) is considered for realistic modeling, which removes the...

BEAVIS: Balloon Enabled Aerial Vehicle for IoT and Sensing

UAVs are becoming versatile and valuable platforms for various applications. However, the main limitation is their flying time. We present BEAVIS, a novel aerial robotic platform striking an unparalleled trade-off between the maneuverability of drones and the long-lasting capacity of blimps. BEAVIS scores highly in applications where drones...

DC Link Capacity Enhancement for MMC-based Distribution Link using Dynamic Voltage Operation

When operating a modular multilevel converter (MMC), a margin appears between the arm voltage and sum capacitor voltage corresponding to the power dependent ripple. This margin can be used to enhance the DC link voltage and increase the transfer capacity of an MMC-based distribution link while keeping the submodule (SM) stresses fixed....

Development of Reliable Power Electronic Systems using Real Time Digital Twin Based Power Hardware-in-the-Loop Testbed

Reliable Power Electronic Systems (PES) are vital for enabling energy transition technologies of the future. Power hardware-in-the-Loop (PHIL) test bed can be used to validate such systems cost-effectively and time-efficiently. In general, the Real Time Digital Twin (RTDT) is a virtual representation of the PES and its operating environment that...

Implementation of Real-Time Digital Twin of Dual Active Bridge Converter in Electrolyzer Applications

Power electronics converters (PEC) play a crucial role in interfacing renewable energy systems and electrolyzers to ensure a high production yield of green hydrogen. The design of such PEC is not straightforward due to the safety hazards of using multiple electrolyzer stacks and converter modules at industrial levels. Therefore, real-time...

Impact of Electrolyzer on the Operation of a Dual Active Bridge Converter

Electrolysis requires a high DC current at low voltage to produce hydrogen from water. Designing power converters for such a load requirement could be challenging while fulfilling the galvanic isolation needs. Therefore, prior knowledge of the electrolyzer's impact on the converter operation should be needed. In this context, this paper...

TestKnight: An Interactive Assistant to Stimulate Test Engineering

Software testing is one of the most important aspects of modern software development. To ensure the quality of the software, developers should ideally write and execute automated tests regularly as their code-base evolves. TestKnight, a plugin for the IntelliJ IDEA integrated development environment (IDE), aims to help Java developers improve...

Additive manufacturing of functionally graded inconel 718: Effect of heat treatment and building orientation on microstructure and fatigue behaviour

This paper addresses the effect of the post-process heat treatments on the microstructure and fatigue crack growth behaviour of the functionally graded (FG) laser powder bed fusion (L-PBF) Inconel 718 (IN718) superalloy. Sets of samples were additively manufactured (AM) altering the process parameters, namely the laser power, the laser...

Adaptive Modularity for Power Electronics Based Electrolysis Systems for Green Hydrogen

Electrolysis holds tremendous potential in reducing the carbon footprint and providing energy dense fuels such as methane. Such systems can be integrated with renewable energy systems with the aid of power electronics interfaces. However, this integration is not straight-forward and imposes various converter design challenges. This paper...

Monitoring Intracellular Metabolite Dynamics in Saccharomyces cerevisiae during Industrially Relevant Famine Stimuli

Carbon limitation is a common feeding strategy in bioprocesses to enable an efficient microbiological conversion of a substrate to a product. However, industrial settings inherently promote mixing insufficiencies, creating zones of famine conditions. Cells frequently traveling through such regions repeatedly experience substrate shortages and...

Effect of microstructure induced anisotropy on fatigue behaviour of functionally graded Inconel 718 fabricated by additive manufacturing

In this paper, the effect of microstructural anisotropy on the fatigue crack growth behaviour of the functionally graded Inconel 718 fabricated through laser powder bed fusion (L-PBF) is investigated. Different manufacturing parameters, including low and high laser powers, were used to produce a variety of non-graded (NG) and functionally...

Nanoelectromechanical resonators from high-T _c superconducting crystals of Bi ₂ Sr ₂ Ca ₁ Cu ₂ O<IMG ALIGN=MIDDLE ALT=-8+δ

In this report, we present nanoelectromechanical resonators fabricated with thin exfoliated crystals of a high-T _c cuprate superconductor Bi ₂ Sr ₂ Ca ₁ Cu ₂ O. The mechanical readout is performed by capacitively coupling their motion to a coplanar waveguide microwave cavity fabricated...

Comparative performance of different scale-down simulators of substrate gradients in Penicillium chrysogenum cultures: the need of a biological systems response analysis

In a 54 m³ large-scale penicillin fermentor, the cells experience substrate gradient cycles at the timescales of global mixing time about 20–40 s. Here, we used an intermittent feeding regime (IFR) and a two-compartment reactor (TCR) to mimic these substrate gradients at laboratory-scale continuous cultures. The IFR was applied to...

Computational fluid dynamics simulation of an industrial P. chrysogenum fermentation with a coupled 9-pool metabolic model: Towards rational scale-down and design optimization

We assess the effect of substrate heterogeneity on the metabolic response of P. chrysogenum in industrial bioreactors via the coupling of a 9-pool metabolic model with Euler-Lagrange CFD simulations. In this work, we outline how this coupled hydrodynamic-metabolic modeling can be utilized in 5 steps. (1) A model response study with a fixed...

Euler-Lagrange analysis towards representative down-scaling of a 22 m3 aerobic S. cerevisiae fermentation

With reaction timescales equal to or shorter than the circulation time, the ideal mixing assumption typically does not hold for large scale bioreactors. As a consequence large scale gradients in extra-cellular conditions such as the substrate concentration exist, which may significantly impact the metabolism of micro-organisms and thereby the...

Euler-Lagrange computational fluid dynamics for (bio)reactor scale down: An analysis of organism lifelines

The trajectories, referred to as lifelines, of individual microorganisms in an industrial scale fermentor under substrate limiting conditions were studied using an Euler-Lagrange computational fluid dynamics approach. The metabolic response to substrate concentration variations along these lifelines provides deep insight in the dynamic...

Elucidation and modeling of the in-vivo kinetics of enzymes and membrane transporters associated with β-lactam and non-ribosomal peptide production in Penicillium chrysogenum

Even 80 years after the discovery of penicillin, it still holds 16% of total antibiotics market. This makes it crucial, from an economical point of view, to improve our understanding of the production organism Penicillium chrysogenum to maximize the penicillin production, as its theoretical yields are far from reached. With the advancement in...