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Recent developments in dc powered technologies have increased interest in highly efficient dc–dc converters, especially at high voltage and high-step voltage ratios. Modular multilevel converters (MMCs) are an attractive alternative approach to this demand because they can manage medium and high dc voltages while using standard semiconductor devices with high efficiency if they employ soft-switching techniques. However, the latest soft-switching techniques require resonant circuits, limiting their operation. This article proposes a new zero-current switching modulation technique for a high-step-ratio MMC dc–dc converter as result of a rms current minimization problem. The proposed optimization generates trapezoidal or triangular current to operate the converter over a wide output voltage and power range, while using a simple control scheme to regulate the output voltage and the voltage balance among the floating cell capacitors. The theoretical analysis has been verified with a laboratory-scaled prototype, demonstrating the effectiveness of the approach and excellent dynamical response.

Se describen e ilustran cuatro nuevas especies de Agrypnini de Chile: Dilobitarsus holomelas sp. nov., D. crassus sp. nov., D. sagittatus sp. nov. y Candanius pehuenche sp. nov. Los ejemplares tipo de Lacon chilensis (Solier, 1851), L. fairmairei (Candèze, 1882) y Dilobitarsus vitticollis (Fairmaire y Germain, 1860) son ilustrados por primera vez. En base a la examinación de este material, el lectotipo y dos paralectotipos de Adelocera vitticollis Fairmaire y Germain, 1860 son designados. Adicionalmente, se aportan nuevos caracteres morfológicos que justifican la sinonimia entre Carlota Arias-Bohart, 2014 y Candanius von Hayek, 1973, y se proporcionan claves actualizadas para el reconocimiento de las especies de Dilobitarsus y Candanius de Chile

The type specimens and specimens labelled as types of unavailable names of the genus Ectinogonia Spinola, 1837 deposited in the Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid (Spain) are catalogued and illustrated. Thirteen type or possible type specimens of five different taxa were found, including the holotype of the subspecies originally described as Ectinogonia (Ectinogonia) melichari rufimarginata Cobos, 1969 (now E. (Kheiliella) melichari rufimarginata).

Pineda, Cristian (2022): Types of the New World Stigmoderini (Coleoptera: Buprestidae) deposited in Finnish Museum of Natural History, Helsinki (Buprestidae: Buprestinae: Stigmoderini). Zootaxa 5134 (3): 435-440, DOI: https://doi.org/10.11646/zootaxa.5134.3.7

A teratological case in a specimen of Glaphyrolytta viridipennis (Coleoptera: Meloidae) from Argentina is described. The case belongs to a multiple homodynamic eschistomelie in the right protarsus of the specimen. The possible causes of this malformation are discussed.

Se describe e ilustra una nueva especie de Candanius de Chile, cuya identidad fue confundida originalmente con C. gracillimus. Se registra la emergencia de un adulto desde madera muerta de molle (Schinus molle L.) y se describe la exuvia de la larva. Adicionalmente, se presenta una clave simplificada para separar las especies conocidas del género.

Dactylozodes descarpentriesi unpublished name [Figure 62A & 62B] Paratype: “Rép. que Argentine Tandil // Brit. Mus 1974-271. // PARATYPUS A. COBOS // D. (Parazodes) descarpentriesi nov. sp. Paratypus A. Cobos det. 1974 // NHMUK 011520994 ”. Paratype: “Rép. que Argentine Tandil // Brit. Mus 1974-271. // PARATYPUS A. COBOS // D. (Parazodes) descarpentriesi nov. sp. Paratypus A. Cobos det. 1974 // NHMUK 011520995 ”. Current status: unpublished name. Comments: Lasionota (Lasionota) descarpentriesi (Cobos, 1974) is an unpublished name., Published as part of Pineda, Cristian & Matsumoto, Keita, 2021, Types of the New World Stigmoderini (Coleoptera: Buprestidae) deposited in Natural History Museum, London Buprestidae: Buprestinae: Stigmoderini, pp. 443-470 in Zootaxa 4964 (3) on pages 465-466, DOI: 10.11646/zootaxa.4964.3.2, http://zenodo.org/record/4714553

The rise of new dc technologies is pushing the development of highly efficient dc-dc converters, especially at high voltage and high step ratio. Modular multilevel converters (MMCs) are an attractive alternative because they can manage medium and high dc voltages with standard semiconductor devices with high efficiency if they employ soft-switching techniques. However, the latest soft-switching techniques have been proposed for fixed voltage range, limiting their operation. This paper proposes a soft-switching modulation for the high step ratio Modular Multilevel dc-dc Converter in extended voltage range. The proposal achieves zero-current switching and regulates the voltage balance among the floating cell capacitors, while using a simple control scheme to regulate the output voltage. The theoretical analysis has been verified with full-scale simulations, demonstrating excellent dynamic response and reduced rms current.

Cascaded H-bridge converters are widely used in the implementation of medium voltage static synchronous compensators (STATCOMs). This is because of the advantages of relatively high-power density and the improved utilisation of low-voltage semiconductor devices. Major concerns with this topology are (i) to ensure a proper balance of the individual DC capacitor voltage in its cells, and (ii) the balancing of the average DC voltage between its clusters. In the research literature, these issues are typically addressed by using centralised control approaches, meaning that both an extensive processing capability and multiple digital outputs and communication channels for the switching signals are required, increasing system complexity. In contrast to this trend, in this paper, a distributed control scheme based on a consensus algorithm is proposed to deal with these issues in a three-phase STATCOM based on a cascaded H-bridge converter. The main advantages of the proposed control scheme are: (i) it does not require a centralised controller, since the cells work autonomously in a cooperative fashion to achieve voltage regulation, distributing the control effort among the cells, and (ii) it increases the fault tolerance of the converter and thus, the reliability of the system by adequately considering its redundancy. Extensive simulation work is provided to validate this proposal, and the characteristics described above.

Recently, Modular Multilevel Converters (MMCs) have become an attractive solution for MV applications. MMCs can handle high voltage levels by interconnecting either full-or half-bridge converters in series, achieving high performance, modularity and excellent power quality. Although most of the reported MMC converters are proposed to interface AC voltages at least in one port, few topologies have been reported for direct DC-DC conversion, mainly intended for interconnection of two DC grids, focusing the most of the reports on the modulation and internal balancing of the converter. In this paper, the output voltage of a high-step ratio DC-DC MMC is controlled to operate as a grid forming converter. Simulation results show excellent performance of the converter, achieving internal voltage balancing and zero current switching operation(ZCS) under steady-state and transient response.

Direct current (Dc) networks have proven advantages in high voltage direct current (HVDC) transmission systems, and now they are expanding to medium- and low-voltage distribution networks. One of the major challenges is to develop reliable dc–dc voltage transformation achieving high efficiency and performance, especially at high voltage and high step ratio. New resonant modular multilevel topologies have arisen as an alternative, mainly because of advantages such as optional use of transformers, natural voltage balance, simple control, and soft-switching capability. However, this type of operation generates a high peak current, does not allow control of power flow in all power range, and has a limited range of voltage variation. This article proposes an asymmetrical triangular current mode applied to high step ratio modular multilevel dc–dc converters. The proposed modulation increases the efficiency and achieves bidirectional control of the power, soft-switching, and a natural balance of the voltage in the cell capacitors. The experimental results show the bidirectional operation and the capacitor voltage balance of the converter under different operating conditions with higher efficiency (97.72%) and lower peak current compared to previous reports of this topology using resonant operation.

Se describen e ilustran cuatro nuevas especies del género Candanius von Hayek de Chile: C. brevipennis sp. nov., C. australis sp. nov., C. ramirezi sp. nov. y C. marmoratus sp. nov. Para cada una de las especies de Candanius, excepto C. australis, se registra la emergencia de adultos desde madera muerta de diferentes especies leñosas. Se designa el lectotipo y paralectotipos de Anius gracillimus Candèze. Adicionalmente, se amplía la distribución conocida de C. gracillimus a la Provincia de Maipo, Chile. Agrypnini, escarabajos click, genitalia, taxonomía.

High voltage direct current (HVDC) transmission systems and low voltage direct current (LVDC) networks are becoming popular due to their advantages and present feasibility, mainly pushed by the advance in power electronics. However, one of the main drawbacks of dc networks is the lack of a dc-dc converter that performs as the ac transformer in terms of efficiency, reliability and high-step voltage ratio, specially in medium and high voltage. Modular multilevel converters are an attractive alternative because they can manage medium and high dc voltages with standard semiconductor devices, and they can achieve high efficiency with soft switching modulation, such as resonant, trapezoidal or triangular currents usually used in double active bridges (DAB). This paper proposes a novel generalized trapezoidal current mode applied to high step ratio Modular Multilevel dc-dc Converters. The proposed modulation increases the efficiency and achieves bidirectional control of the power, soft-switching and a natural balance of the voltage in the capacitors. The simulation results show the bidirectional operation and the capacitor voltage balance of the converter under different operating conditions with high efficiency (98.2%).

In this paper is presented a simple method to design an inductor for high performance on a DC-DC Modular Multilevel Converter(MMC). This element is one of the main limitations for a proper fulfilment. A high-frequency inductor for high power applications is a key element to achieve high efficiency in such type of converters. The theoretical design of the inductor is compared with an experimental prototype, which is then implemented in a high-power DC-DC converter. Experimental results validate the accuracy of the theoretical design and the improvements in the efficiency of the overall DC-DC high power converter.

Lampygnatha ikuoi gen. & sp. nov. is described and illustrated from southeast Brazil. A hypothesized mimicry complex that involves the new taxon, Allocerus spencei Kirby (Coleoptera: Cerambycidae) and Cratomorphus splendidus (Drury, 1782) (Coleoptera: Lampyridae) is discussed. A key to the identification of all genera of New World Stigmoderini is presented.

Conognatha (Pithiscus) mielkei Pineda, Barros and Koike n. sp. (Coleoptera: Buprestidae), from southeast Brazil is described and illustrated. We also report five new state records for Brazil for the following species: Conognatha (C.) ovatula, Conognatha (P.) apicalis, C. (P.) excellens, C. (P.) insignis and C. (P.) sellovii.

DC networks have generated much interest in recent years, from transmission in high voltage to their use in distribution systems. One of the major challenges is to replace the high efficient and reliable ac transformer, especially at high voltage and step ratio. New resonant modular multilevel topologies have arisen as an alternative, mainly because of advantages such as optional use of transformers, natural voltage balance, simple control and soft-switching. However, this type of operation generates a high peak current, does not allow control of power flow in all power range and has a limited range of voltage variation. This paper proposes an asymmetrical triangular current mode applied in high step ratio Modular Multilevel dc-dc Converters that achieves bidirectional control of the power, soft-switching and a natural balance of the voltage in the capacitors. The simulation results show the bidirectional operation and the capacitor voltage balance of the converter under different operating conditions with high efficiency and low peak current compared to resonant mode. The proposal was tested in a down-scale prototype, confirming the operation principle.

Ancylotela angustinotum Pineda, new species (Coleoptera: Buprestidae), is described and illustrated from a single female specimen collected in San Juan Province, Argentina. The new taxon is easily distinguished from Ancylotela oculata Waterhouse, 1882 by its subparallel-sided body shape, pronotum almost as long as wide, and large, M-shaped elytral spots.