1,720,965 research outputs found
Hairpin-Wound Rim-Driven Propeller for Electric Boats on Inland Waterways
No full textElectric mobility on water is in the early stage of development but has a great potential, especially when considering inland waterway vessels. Inland waterway vessels are the best candidate to benefit from a battery electric propulsion system, since they typically operate in environments with restrictions on noise and emissions; they have short ranges and are relatively close to charging infrastructures. Rim-driven propellers actuated by large diameter hollow-shaft electrical machines are a promising technology. Rim-driven propellers present a number of advantages when compared to standard propellers, such as increased efficiency and a compact structure that is particularly suitable for small and lightweight boats. The present work details the design and numerical simulation of the electric machine for rim-driven propeller pod applied to a speedboat to be used on lakes and rivers. The electric machine main distinctive features are a high power density, a thin radial section and a hairpin winding construction
Assessment of a Multi-Functional Converter System for Traction Electric Drives
No full textThe introduction of strict regulations in terms of air pollution is pushing automotive industry and heavy equipments vehicles manufacturers to integrate electric drives into the powertrain. To overcome the limitations on maximum battery voltage, a DC-DC bidirectional boost converter stage between the battery and the inverter is widely adopted by manufacturers. However, these converters are bulky, expensive and impact on the system efficiency. For this reason, Multi-Functional Converter Systems (MFCS) have been introduced in order to avoid the voltage boost stage and take advantage of the electric motor and the inverter to integrate the boost converter within these two components. This paper carries out a comparison between a traditional architecture, with a DC-DC boost converter stage, and a MFCS, to determine the best solution in terms of efficiency, weight and encumbrance
Design and Optimization of a Magnetic Gear for a Conveyor System Application
No full textMagnetic gears have some advantages when compared to the traditional mechanical ones, especially in terms of maintenance and absence of lubrication. Many types of magnetic gears have been presented in the last years, with the aim of pushing the torque density to very high levels.This paper deals with the design and optimization of a magnetic gear (MG) for an industrial conveyor system. The design was carried out considering the geometrical constraints and the gear ratio imposed by the target application, with the aim of reducing the torque ripple and obtaining a balanced radial attraction force on the segmented ring. Two different internal permanent magnet inner rotor geometries were drafted and optimized by means of finite element simulations. The different designs were compared against each other by means of different figures of merit, including torque ripple, radial force on the segmented ring, power losses and mass of the permanent magnets
Modular Multi-Three-Phase Electric Drives for Enhanced Reliability and Current Ripple Minimization
No full textReconfigurable Multi-Three-Phase Drive for Naval Rim-Driven Propulsion System
No full textMultiphase drives are the subject of great interest for the transportation electrification. Multi-three-phase machines are used with modular three-phase converters to obtain a redundant structure and their great advantage is the fault-tolerance capability. Starting from a symmetrical multi-three-phase machine, a reconfigurable architecture drive can be obtained. The main characteristic of a reconfigurable architecture is the ability to change the winding configuration to better match the operating point, specifically the machine speed. The main advantage of this architecture is the capability of reducing the number of active converters when the machine operates at low speed, thus reducing total converter power losses. However, system complexity increases, since reconfiguration cells are needed to interconnect the winding sets. The proposed reconfigurable multi-three-phase drive architecture exhibits two main benefits at low speed operation: increased efficiency and reduced phase current ripple for a given switching frequency. The reconfigurable architecture was assessed by means of analytical as well as numerical simulations, and the benefits obtainable at low speed operation were also demonstrated experimentally on a reduced scale prototype, capable of 'on the fly' reconfiguration without stopping the machine
Assessment of master-slave and droop control strategies in multi-three-phase drives
No full textMulti-phase electric drives can be employed in a great variety of applications. Their advantage in terms of fault-tolerance capability is becoming the focus of the work of many research activities, especially in the field of transportation electrification. The main topic is to create redundant and modular multi-three-phase drives to increase the overall system reliability and fault-tolerance. To this aim, distributed control architectures have been assessed. In this paper, a centralized master-slave control is compared against a distributed droop control architecture, in order to identify advantages and drawbacks. Both of the control strategies are applied to a double three-phase drive. The aim of the work is to assess whether the droop control architecture can be a valid alternative to a centralized master-slave control in terms of performances, but with the additional benefit of having a proper full redundant fault-tolerant application
Multi-three-phase propulsion system for fault-tolerant naval rim-driven propeller
No full textMulti-phase machines are gaining popularity especially in the field of transportation electrification. Multi-three-phase machines used in conjunction with modular three-phase converters result in a redundant structure with the great advantage of fault-tolerance operation capability. The present work reports the study of a multi-three-phase machine for a rim-driven propeller pod, to be employed in yachting boat electrification. The design of the machine, i.e. annular construction with large hollow shaft, was chosen to satisfy the constraints for the integration into the existing propulsion pod and to meet the reference nominal torque and speed for the inner propeller design. Detailed simulation of losses, including the effect of PWM modulation, was performed to assess the machine losses and to define the optimal switching frequency suitable for the drive. The study then focused on the fault operation capability by calculating the radial force acting on the machine rotor under different fault scenarios
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