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European legislation on building performance and energy efficiency pushes the shift towards minimizing the environmental footprint of buildings. Buildingintegrated photovoltaics (BIPV) is a promising technology that can accelerate the transition to energy-neutral buildings. Quantifying the potential of BIPV is crucial and one means of obtaining those results is through simulation. The state-of-the-art tools offer either thermal or electrical specialization; in particular, balance of system components (BOS) such as power converters have not been studied in detail within the building simulations BIPV domain. In this paper, a multi-physics model of a BIPV integrated DC/DC converter is developed in the Modelica language, taking into account the thermal and electrical couplings inherent to power electronic systems. The model has been validated using representative outdoor BIPV measurements and a DC/DC converter prototype. It has been found that the proposed model provides reasonable accuracy and outperforms an equivalent power conditioning model in TRNSYS. To demonstrate the model's functionality, two case studies are performed. First, the temperature-dependence of the converter's efficiency and losses is quantified and analyzed and, second, the prominent contributors to the converter losses are identified and discussed.

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This work focuses on a Quasi-Two-Level (Q2L) converter topology for medium voltage drives (MVDs). It targets applications where the drive and the motor are connected via a long cable. In such systems a dv/dt filter is usually placed between the drive and motor to increase the rise time of inverter output voltage pulses, and thereby reduce the motor terminal overvoltage. The Q2L converter allows for an intrinsic reduction in the motor terminal overvoltage by dividing the voltage transitions in the inverter output voltage waveform into multiple smaller steps. Simulation results obtained with a distributed parameter cable model are presented, which show that the Q2L converter can offer lower converter capacitor energy and reduced dv/dt filter component values for a given motor terminal overvoltage requirement compared to the 5LANPC, a conventional MVD topology, at the cost of worse WTHD and efficiency.

Building-Integrated Photovoltaics (BIPV) replace traditional building elements with power generating elements through the use of solar cells. One of the targets for this technology is to place the module-level power converter into the photovoltaic module's frame to achieve an integrated system. Temperature is the most influential parameter for a converter's reliability, its damage caused on the components needs to be studied in detail. In this paper, a reliability comparison based on a four-day mission profile has been made in order to assess the most reliable frame position for this converter to be placed in as all of them possess a different temperature profile. The results show that placing the converter in the lateral bottom of the frame is significantly more reliable than the mid or top position. In addition, a lifetime analysis is performed on the converter's dc-link capacitor in order to demonstrate the required methodology. In future work, this can be extended towards other sensitive components when appropriate lifetime models become available. These lifetime estimations can then be combined to achieve an overall BIPV system lifetime assessment.

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We study the mechanisms of pattern formation for vegetation dynamics in water-limited regions. Our analysis is based on a set of two partial differential equations (PDEs) of reaction-diffusion type for the biomass and water and one ordinary differential equation (ODE) describing the dependence of the toxicity on the biomass. We perform a linear stability analysis in the one-dimensional finite space, we derive analytically the conditions for the appearance of Turing instability that gives rise to spatio-temporal patterns emanating from the homogeneous solution, and provide its dependence with respect to the size of the domain. Furthermore, we perform a numerical bifurcation analysis in order to study the pattern formation of the inhomogeneous solution, with respect to the precipitation rate, thus analyzing the stability and symmetry properties of the emanating patterns. Based on the numerical bifurcation analysis, we have found new patterns, which form due to the onset of secondary bifurcations from the primary Turing instability, thus giving rise to a multistability of asymmetric solutions.