1,721,037 research outputs found
Special Issue on More Electric Aircraft
No full textElectrification is a remarkable trend in the aviation industry. Electric machines and power electronics systems have been increasingly embedded in aerospace applications. In this field, the abovementioned systems are mainly used for flight control, engine starting/generating, propulsion, environmental control, braking, and fuel and hydraulic pumps
A Five-Level Single-Phase Grid-Connected Converter for Renewable Distributed Systems
No full textIn low-power renewable systems a single-phase grid-connected converter is usually adopted. This paper deals with a novel five-level converter topology that follows this trend. A review of the state of the art of the five-level topologies and a theoretical power loss comparison with the proposed solution is realized. The proposed converter architecture is based on a full-bridge topology with two additional power switches and two diodes connected to the midpoint of the DC Link. Since the two added levels are obtained by the discharge of the two capacitors of the DC Link, the balancing of the midpoint voltage is obtained with a specific PWM strategy. Simulation and experimental results show the effectiveness of the proposed solution
A Time-Saving Approach for the Thermal Lifetime Evaluation of Low-Voltage Electrical Machines
No full textModern electrical machines, such as those employed in transportation applications are required to provide very high performance in terms of power (and torque) density and efficiency. The reality, however, is that the more these machines are 'pushed' in relation to power density, the more is the probability of failure of their insulation systems, through enhanced electrical and thermal stresses. On the other hand, regardless the power density level, the electrical machine still needs to respect the certification processes set by the international standards and procedures. Unfortunately, today reliability and lifetime are still not considered as main design objective functions right from the start of the design process. This is a direct result of a gap in knowledge in terms of the precise understanding of failure mechanisms. If physics of failure models are available, then reliability can be included at all design stages. Therefore, this article proposes a method that shortens the time demanded for the thermal lifetime evaluation procedure or qualification of low-voltage electrical machines. The theory behind the method is presented and, then, experimentally validated on custom designed specimens
FemtoCore enabled quasi-distributed Control for Modular Multilevel Converters
No full textThe development of the processing capability has enabled the implementation of advanced control systems for power electronics converters. In this framework, the modular multilevel converter has attracted the attention of industry and academia, thanks to the good performance in terms of power quality, wide voltage capability, and fault tolerance, which are key requirement for high power applications. This paper proposes a quasi distribute control architecture based on a FemtoCore platform, an optimized soft-core designed for modular power electronics applications. Latency estimates and simulation results shows the potential of this solution for the control of modular multilevel converters
Effect of semiconductor parasitic capacitances on ground leakage current in three-phase current source inverters
Full text linkThis paper investigates the influence of power semiconductor parasitic components on the ground leakage current in the three-phase Current Source Inverter topology, in the literature called H7 or CSI7. This topology allows reducing converter conduction losses with respect to the classic CSI, but at the same time makes the topology more susceptible to the parasitic capacitances of the semiconductors devices. In the present work, a grid-connected converter for photovoltaic power systems is considered as a case study, to investigate the equivalent circuit for ground leakage current. The same analysis can be extended to applications regarding electric drives, since the HF model of electric machines is characterized by stray capacitance between windings and the stator slots/motor frame. Simulation results proved the correctness of the proposed simplified common-mode circuit and highlighted the need of an additional common-mode inductor filter in case of resonance frequencies of the common-mode circuit close to harmonics of the power converter switching frequency. Experimental results are in agreement with the theoretical analysis
Information technologies for distributed machine drives: An overview
No full textThe exponential growth experienced by the semiconductor manufacturing field has led to a large proliferation of devices with large amounts computational power, enabling countless technologies and revolutionizing many fields. Control systems and machine drives are certainly among them. Much research is being carried out to develop multi-phase and fully segmented machines, with their inherent fault tolerance. To take full advantage of the redundancy and load sharing capabilities of the machine structure, with multiple winding sets, a suitable distributed control method must be used. A high performance network between the drives is thus required. This paper will present an overview of the available communication protocols that are used in the field and evaluate how suitable are they to this new class of very demanding real time tasks
Multiphase fault tolerant distributed control techniques for integrated drives based on resonant regulators
No full textOne of the challenges brought forward by the gradual electrification undertaken by the aviation sector is the requirement of fault tolerance for machine drive systems to be used for critical on-board tasks such as propulsion or primary flight surface actuation. Their inherent advantages in both volumetric and gravimetric power density makes integrated drives the prime candidates for these applications. Despite the large advances in this field, few key area still need work. Key among which is fault tolerant current control strategies. This paper studies the application of resonant control techniques to achieve a scalable and fault tolerant current control strategy for multiphase machine
A Scalable System Architecture for High-Performance Fault Tolerant Machine Drives
Full text linkWhen targeting mission critical applications, the design of the electronic actuation systems needs to consider many requirements and constraints not typical in standard industrial applications. One of these is tolerance to faults, as the unplanned shutdown of a critical subsystem, if not handled correctly, could lead to financial harm, environmental disaster, or even loss of life. One way this can be avoided is through the design of an electric drive systems based on multi-phase machines that can keep operating, albeit with degraded performance, in a partial configuration under fault conditions. Distributed architectures are uniquely suited to meet these challenges, by providing a large degree of isolation between the various components. This paper presents a system architecture suitable for scalable and high-performance fault tolerant machine drive systems. the effectiveness of this system is demonstrated through theoretical analysis and experimental verification on a six-phase machine
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