Electro-Thermal Model-Based Design of Bidirectional On-Board Chargers in Hybrid and Full Electric Vehicles

In this paper, a model-based approach for the design of a bidirectional onboard charger (OBC) device for modern hybrid and fully electrified vehicles is proposed. The main objective and contribution of our study is to incorporate in the same simulation environment both modelling of electrical and thermal behaviour of switching devices. This is because most (if not all) of the studies in the literature present analyses of thermal behaviour based on the use of FEM (Finite Element Method) SWs, which in fact require the definition of complicated models based on partial derivative equations. The simulation of such accurate models is computationally expensive and, therefore, cannot be incorporated into the same virtual environment in which the circuit equations are solved. This requires long waiting times and also means that electrical and thermal models do not interact with each other, limiting the completeness of the analysis in the design phase. As a case study, we take as reference the architecture of a modular bidirectional single-phase OBC, consisting of a Totem Pole-type AC/DC converter with Power Factor Correction (PFC) followed by a Dual Active Bridge (DAB) type DC/DC converter. Specifically, we consider a 7 kW OBC, for which its modules consist of switching devices made with modern 900 V GaN (Gallium Nitrade) and 1200 V SiC (Silicon Carbide) technologies, to achieve maximum performance and efficiency. We present a procedure for sizing and selecting electronic devices based on the analysis of behaviour through circuit models of the Totem Pole PFC and DAB converter in order to perform validation by using simulations that are as realistic as possible. The developed models are tested under various operating conditions of practical interest in order to validate the robustness of the implemented control algorithms under varying operating conditions. The validation of the models and control loops is also enhanced by an exhaustive robustness analysis of the parametric variations of the model with respect to the nominal case. All simulations obtained respect the operating limits of the selected devices and components, for which its characteristics are reported in data sheets both in terms of electrical and thermal behaviour.

4d Chern-Simons theory as a 3d Toda theory, and a 3d-2d correspondence

We show that the four-dimensional Chern-Simons theory studied by Costello, Witten and Yamazaki, is, with Nahm pole-type boundary conditions, dual to a boundary theory that is a three-dimensional analogue of Toda theory with a novel 3d W-algebra symmetry. By embedding four-dimensional Chern-Simons theory in a partial twist of the five-dimensional maximally supersymmetric Yang-Mills theory on a manifold with corners, we argue that this three-dimensional Toda theory is dual to a two-dimensional topological sigma model with A-branes on the moduli space of solutions to the Bogomolny equations. This furnishes a novel 3d-2d correspondence, which, among other mathematical implications, also reveals that modules of the 3d W-algebra are modules for the quantized algebra of certain holomorphic functions on the Bogomolny moduli space.

Morphological and Yield Traits of Pole-Type French Bean Genotypes

Understanding the phenotypic variation and association between the grain yield, and other agronomic traits in French bean genotypes is important for its varietal improvement program. Field experiments were conducted during 2018 and 2019 cropping season at Horticulture Research Station, Dailekh, Karnali Province of Nepal to evaluate pole-type French bean genotypes for plant morphological characters, yield and the association between the agronomic traits. Twelve (Bhatte, Chaumase, Dhankute Chhirke, WP Con Bean, White OP, Dhundi Raj, LB-31, LB-37, LB-39, Madhav, Chinese Long, and Trishuli) pole-type French bean genotypes were laid out in a randomized complete block design (RCBD) with three replications. Pole-type French bean genotypes showed the significant variation for plant morphological traits and grain yield. Genotype LB-31 exhibited significantly the highest pod number (78.0/plant), green pod weight (675.0 g/plant), green pod yield (36.1 t/ha), and dry grain yield (2.4 t/ha). Following LB-31 genotype, genotype Chaumase and LB-39 produced the highest green pod yield (31.3 t/ha and 31.2 t/ha, respectively). The number of clusters per plant, pod number per plant and green pod weight per plant exhibited the significant positive correlation with green pod and dry grain yield. Hence, these traits can be selected to improve the yield potential of pole-type French bean genotypes. Pole type French bean genotypes used in the experiment were well adapted to the study area. Therefore, the high yielding genotypes viz LB-31, Chaumase and LB-39 could be recommended to use as seed source for on-farm production in Mid-Western Nepal.

Comparative study of partitioned stator flux-modulation motors with different permanent magnet arrays

By incorporating the merits of partitioned stator and flux modulation techniques, the partitioned stator flux modulation motors featuring high torque, have attracted much attention. This paper investigates four partitioned stator flux modulation motors with different types of PM arrays, including surface-mounted type, consequent-pole type, Halbach-array type, and half-Halbach type. The influences of key parameters on the average electromagnetic torque is conducted and compared. Then, based on the optimal designs, four motors are compared in terms of magnetic field distribution, back-electromotive force, torque characteristics, loss and overload ability. The result reveals that the half-Halbach motor is capable of utilizing more PM to improve electromagnetic torque. Also, the consequent-pole motor achieves the highest torque per PM usage. In addition, performance comparison under the same PM usage is carried out. The result shows that the half-Halbach motor not only exhibits the highest average torque but also achieves the highest PM utilization. Last, the prototype of half-Halbach motor is built for experimental verification.

Variability and Genetic Divergence in Vegetable Cowpea Germplasm of Goa

Vegetable cowpea or Yard long bean [Vigna unguiculata var. sesquipedalis L. (Walp)] is a warm season leguminous crops grown especially for vegetable purpose along the west coast of India. In Goa, pole type varieties are preferred over bushy types as they offer multiple harvests with comparatively longer pods. There is wide variability found for different morphological and other traits in the local types cultivated in the state of Goa. Exploration of genetic variability in the available germplasm is a prerequisite for initiation of any successful breeding programme. Twenty nine genotypes of vegetable cowpea including three improved varieties collected from different parts of Goa state were evaluated for twelve quantitative characters including yield. High variability was observed for pod yield/plant, number of pods/plant and pod length. The high variability for pod yield per plant is apparent as the pod yield ranged from 315.25 to 2070.45 g/plant with an average of 827.48 g per plant. Pod yield depends on number of pods per plant, pod length and pod weight. Number of pods per plant ranged from 36.65 to 147.80. Pod weight depends on pod length, number of seeds per pod and hundred seeds weight. Wide variation was observed for all these characters in the present study. The GCV value was maximum for pod yield per plant (g) followed by pod weight (g) and number of pods per plant. Low values of GCV were observed for days to first flowering, days to first harvest and number of seeds per pod. In the present study, the twenty nine genotypes could be grouped into fourteen clusters based on genetic distance. High coefficient of variation was observed for pod yield per plant, pod weight, number of pods per plant and pod length indicating their significant contribution in determining the inter cluster distances.

Jenis-Jenis Vegetasi di Area Penangkaran Burung Maleo Desa Taima Kecamatan Bualemo Kabupaten Banggai

Macrocephalon maleo an endemic bird species to Sulawesi and classified as Endangered by the IUCN and on the Government of Indonesia's list of priority species for conservation. The study was conducted in April - July 2019, data collection was taken from nesting ground of the maleo bird in Taima Village, sub district Bualemo, districs Banggai. Data were collected from two transects on 5 plots, and were analysed its relative frequency distribution. The results showed that there were 18 plant species for all plots. In tree species plots are dominated by Quassia indica (29.42%), pole type plots are dominated by Thespesia populnea (11.86%), sapling plots are dominated by Cycas sp. (9.81%) and bush species plots were dominated by Justicia sp. L (31.98%). The results others showed that habitat Maleo at both locations consisted of trees with 7-15 meters tall and shrubs. Keywords: vegetation, plant, maleo, taima village.