http://hdl.handle.net/20.500.12367/2205 Sat, 25 Apr 2026 23:38:44 GMT 2026-04-25T23:38:44Z http://hdl.handle.net/20.500.12367/2843 Electric vehicle powertrains with modular battery banks tied to multilevel NPC inverters Busquets-Monge, Sergio; Alepuz, Salvador; Garcia-Rojas, Gabriel; Bordonau, Josep Nowadays, the internal combustion engine in vehicles is being replaced by electric motors, giving way to the electric vehicle, which results in reduced environmental impact, higher efficiency and lower emission of greenhouse gases. The powertrain of an electric vehicle is its most prominent subsystem, with the batteries and traction inverter being key components. Thus, due to their relevance, advances in the design of both components are of paramount importance. In this paper, the potential benefits achieved through a powertrain design approach based on combining a modular battery bank with multilevel NPC traction inverter topologies were analyzed, in comparison to a conventional two-level powertrain design. Several aspects were analyzed: modularity, complexity, battery-pack state-of-charge balancing, inverter loss, motor ac voltage harmonic distortion, motor common-mode voltage and reliability. [...] Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.12367/2843 2023-01-01T00:00:00Z http://hdl.handle.net/20.500.12367/2836 Active thermal control in neutral-point-clamped multilevel converters based on switching-cell arrays Alepuz, Salvador; Nicolas-Apruzzese, Joan; Rafiezadeh, Roya; Busquets-Monge, Sergio; Raya Di Francisco, Mariana Candela; Filba-Martinez, Alber Neutral-point-clamped multilevel converters are a suitable solution to the implementation of low–medium voltage and power applications at present, thanks to their intrinsic superior voltage and current quality. The conventional configurations of these converters present uneven power loss distribution, causing thermal stress in some power semiconductors, which weakens the power converter reliability. To overcome this, an implementation of the neutral-point-clamped multilevel converter based on a switching-cell array is introduced, adding redundant conduction paths on one side and more options to distribute the switching losses on the other side. An active thermal control is proposed to balance the temperature distribution in the converter. A four-level converter has been implemented to evaluate the proposed solution. [...] Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.12367/2836 2023-01-01T00:00:00Z http://hdl.handle.net/20.500.12367/2593 Fast reliability assessment of neutral-point-clamped topologies through Markov models Busquets-Monge, Sergio; Rafiezadeh, Roya; Alepuz, Salvador; Filba-Martinez, Alber; Nicolas-Apruzzese, Joan This article presents detailed Markov models for the reliability assessment of multilevel neutral-point-clamped (NPC) converter leg topologies, incorporating their inherent fault-tolerance under open-circuit switch faults. The Markov models are generated and discussed in detail for the three-level and four-level active NPC (ANPC) cases, while the presented methodology can be applied to easily generate the models for a higher number of levels and other topology variants. In addition, this article also proposes an extremely fast calculation method to obtain the precise value of the system's mean time to failure from any given formulated system Markov model. This method is then applied to quantitatively compare the reliability of two-level, three-level, and four-level ANPC legs under switch open-circuit-guaranteed faults and varying degrees of device paralleling. [...] Tue, 08 Jun 2021 00:00:00 GMT http://hdl.handle.net/20.500.12367/2593 2021-06-08T00:00:00Z http://hdl.handle.net/20.500.12367/2214 A survey on capacitor voltage control in neutral-point-clamped multilevel converters Alepuz, Salvador; Busquets-Monge, Sergio; Nicolas-Apruzzese, Joan; Filba-Martinez, Alber; Bordonau, Josep; Yuan, Xibo; Kouro, Samir Neutral-point-clamped multilevel converters are currently a suitable solution for a wide range of applications. It is well known that the capacitor voltage balance is a major issue for this topology. In this paper, a brief summary of the basic topologies, modulations, and features of neutral-point-clamped multilevel converters is presented, prior to a detailed description and analysis of the capacitor voltage balance behavior. Then, the most relevant methods to manage the capacitor voltage balance are presented and discussed, including operation in the overmodulation region, at low frequency-modulation indexes, with different numbers of AC phases, and with different numbers of levels. Both open- and closed-loop methods are discussed. Some methods based on adding external circuitry are also presented and analyzed. Although the focus of the paper is mainly DC–AC conversion, the techniques for capacitor voltage balance in DC–DC conversion are discussed as well. Finally, the paper concludes with some application examples benefiting from the presented techniques. Thu, 10 Feb 2022 00:00:00 GMT http://hdl.handle.net/20.500.12367/2214 2022-02-10T00:00:00Z