1,720,999 research outputs found
Extended MTPA and Flux-Weakening Control with Total Copper Loss Minimisation and Transient Torque Compensation for Wound-Rotor Synchronous Machines
No full textWound Rotor Synchronous Machine (WRSM), namely Electrically Excited Synchronous Machine (EESM) and Hybrid Excited Synchronous Machine (HESM), can represent effective solutions to address the concerns raised by the use of Rare Earth Elements (REE) in Permanent Magnet Synchronous Machines (PMSMs), which involve geopolitical implications, environmental impact and cost. The possibility to vary the rotor excitation brings opportunities (especially in Flux-Weakening operation, FW), but also some additional challenges, namely in the selection of the optimal operating point in terms of stator and rotor currents. This paper analyses the operation of EESM and HESM and proposes a strategy for the minimisation of overall Joule losses. A comprehensive control scheme will be developed, which achieves smooth and efficient operation across the whole speed range. An "Extended MTPA"strategy is proposed in the low-speed range, while a closed-loop FW algorithm is proposed for the high-speed. Furthermore, the torque actuation lag issue (related to the slow dynamics of the rotor current) is addressed by providing a novel compensation strategy
5-hydroxytryptamine3 receptors sited on cholinergic axon terminals of human cerebral cortex mediate inhibition of acetylcholine release
No full textIntegrated Battery Modular Multilevel Converter based Drive for Electrically Excited and Hybrid Excited Synchronous Machines
No full textThis paper proposes a sustainable solution for high-voltage and high-capacity battery-powered traction systems that addresses the dependency on Rare Earth materials for the machine's Permanent Magnets (PMs), aiming at eliminating or significantly reducing their usage. To achieve this goal, the paper advocates for the adoption of Electrically Excited Synchronous Machines (EESM) and Hybrid Excited Synchronous Machines (HESM) as ideal candidates, eliminating the need for permanent magnets while maintaining high-performance capabilities. Furthermore, integration of the On-Board Charger (OBC) and Battery Management System (BMS) functionality with the traction converter itself offers an opportunity to simplify the design of the overall system and limit the total part count, which can be a challenge for transportation applications with high-power demand and space constraints. Moreover, the battery pack's voltage levels are observed to be increasing, requiring a modular approach to accommodate evolving voltage requirements effectively. The proposed drive is based on an Integrated Battery Modular Multilevel Converter (IB-MMC) in conjunction with an Electrically Excited Synchronous Machine, which completely avoids the use of Permanent Magnets for traction. The simulation results are provided to demonstrate the effectiveness of the proposal
A microplate-based colorimetric assay of the total peroxyl radical trapping capability of human plasma.
No full textModular Multilevel Converters for Next-Generation Electric Arc Furnaces in Steelmaking Electrification
No full textOngoing effort towards the decarbonization of steelmaking requires the widespread adoption of Electric Arc Furnaces (EAFs). Due to the variability of load and its effect on the upstream grid, the adoption of inverter-based solutions is largely beneficial, yet not widespread. Due to the different requirements in terms of arc operating voltages which depend on plant power ratings, the Modular Multilevel Converter (MMC) is a prominent candidate. However, several challenges need to be solved, such as the high reactive power, variability, and load imbalance, all of which strongly affect the stability of the voltage of the modules. The adoption of an MMC for EAF supply is proposed and analyzed in this work, starting from a brief review of the existing solutions. The peculiarities of this application related to its design and control are reported for the first time. An effective current control strategy is also proposed, allowing to achieve excellent control performance. Simulations based on realistic system parameters and conditions demonstrate the feasibility and effectiveness of the proposal
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