Dead Time Management in GaN Based Three-Phase Motor Drives

This paper deals with the dead time selection in Gallium Nitride (GaN) FET based three-phase brushless DC motor drives. The GaN wide-bandgap (WBG) technology enables the increase of the switching frequency compared with silicon MOSFET. In inverter applications, it is necessary to insert a dead time in the switching signals, to avoid cross conduction in the inverter leg. The dead time selection is a compromise between the switching time and the quality of the inverter output waveforms. GaN FETs can operate with dead times in the range of tens of ns. In this paper the advantages of the GaN technology in the reduction of dead time in terms of output waveforms distortion and speed ripple compared with silicon MOSFET are carried out. Furthermore, an evaluation on the dead time compensation technique compared with the hardware technology reduction is investigated demonstrating the effectiveness and the saving of software and hardware resources obtained by GaN FET devices

Torque Control Accuracy Using Different Techniques for Determination of Induction Motor Rotor Time Constant

Abstract – Induction motor (IM) drives represent a competitive solution for both industry and transports electrification. Most control solutions for induction motors currently perform the torque regulation by implementing field- oriented control (FOC) algorithms schemes defined in rotating dq coordinates. According to this scenario, the estimation of the d-axis position covers a key role to get good accuracy of the torque regulation. If considering the low-speed operation of the motor, the torque control performance is significantly affected by the accuracy in estimating the rotor time constant. According to the literature, this parameter can be computed using either the results of standard- (no-load and locked rotor tests) or flux-decay tests. However, these tests get unequal values of the rotor time constant, thus leading to a different torque control performance. Therefore, this paper aims at investigating the best value of the rotor time constant to optimize the accuracy of the FOC-based torque control. Experimental results obtained on a 4 poles IM, rated 10 kW at 6000 r/min, are presented

Electric vehicle ultra-fast battery chargers: A boost for power system stability?

As a consequence of the exponential growth of the electric vehicle (EV) market, DC fast-charging infrastructure is being rapidly deployed all around the world. Ultra-fast charging (UFC) stations are starting to pose serious challenges to the electric power system operation, mostly due to their high peak power demand and unregulated discontinuous operation. To address these issues, local energy storage can be installed, ensuring a smoother grid power absorption profile and allowing to provide grid-supporting features. In this work, a control solution for the grid-side AC/DC converter of next-generation EV UFC stations is proposed. A virtual synchronous compensator (VSC) control algorithm is implemented, in order to lessen the impact of the charging station on the utility and to provide the full spectrum of grid ancillary services (i.e., frequency regulation, reactive power compensation, harmonic reduction, short circuit current generation, etc.). The proposed control strategy is verified experimentally on a downscaled 15 kVA three-phase inverter, emulating the grid front-end of the charging station

Admittance Model Identification of Inverters using Voltage Injection

The advancements in power electronics are leading to a growing number of electronic converters connected to the electric grid. Even though this enables a more efficient transformation and use of energy, the harmonic interaction between converters can cause instabilities in the network. Therefore, it is important to model the individual converters and their interconnection in an efficient way, in order to study the global stability of the system. A promising modelling strategy analytically derives the equivalent admittance of the converters. However, due to industrial secrecy issues, experimental identification methods are also necessary to obtain the converter equivalent admittance with a black-box approach. This paper analyses the experimental characterization of inverters using the voltage injection method. A detailed explanation of the theoretical background of this method and its practical implementation are provided

Fault-Tolerant Torque Controller Based on Adaptive Decoupled Multi-Stator Modeling for Multi-Three-Phase Induction Motor Drives

Among the multiphase solutions, multi-three-phase drives are becoming more and more widespread in practice as they can be modularly supplied by conventional three-phase inverters. The literature reports several control approaches to perform the torque regulation of multi-three-phase machines. Most of such solutions use the vector space decomposition (VSD) approach since it allows the control of a multi-three-phase machine using the conventional control schemes of three-phase drives, thus reducing the complexity of the control algorithm. However, this advantage is practically lost in the case of open-three-phase faults. Indeed, the postfault operation of the VSD-based drive schemes requires the implementation of additional control modules, often specifically designed for the machine under consideration. Therefore, this article aims to propose a novel control approach that allows using any control scheme developed for three-phase motors to perform the torque regulation of a multi-three-phase machine both in healthy and faulty operation. In this way, the previously mentioned drawbacks of the VSD-based control schemes in dealing with the faulty operation of the machine are avoided. Moreover, the simplicity of the control algorithm is always preserved, regardless of the machine's operating condition. The proposed solution has been experimentally validated through a 12-phase induction motor, rated 10 kW at 6000 r/min, using a quadruple-three-phase configuration of the stator winding

H-Bridge Converter as Basic Switching Topology Workbench in Power Electronics Teaching

This article deals with an effective power electronics learning setup based on a Full-Bridge converter used to teach electrical energy conversion experimentally. In the proposed learning by doing methodology, the hardware and the software are properly mixed in order to obtain an easy-to-use experimental learning environment. In this paper, the H-Bridge is the fundamental brick to build students’ knowledge on the main topics of power electronics converter circuit in different operative conditions. This H-Bridge comes with a reconfigurable output LCL to achieve several basic DC-DC powerconverters topologies. Converter current and voltage switching behavior can be investigated using the proposed setup. Furthermore, the friendly hardware and software set-up allows studying the converter modulation and control techniques of the different power electronics circuits

Hybrid Battery Systems: An Investigation for Maritime Transport

Received: 19 June 2023. Revised: 25 July 2023. Accepted: 2 August 2023. Available online: 25 September 2023.The electrification of naval propulsion systems is increasingly investigated as a promising avenue to reduce CO2 emissions. This study explores the application of electric propulsion in diverse waterborne transport sectors, ranging from commercial and industrial cargo ships to naval vessels, passenger cruise liners, ferries, and small recreational boats. In these systems, propellers are powered by large electric motors, which are progressively transitioning to induction or synchronous multiphase solutions. A crucial component of these systems is the Battery Storage System (BSS), which is integrated with an energy storage management system to create a grid that powers the electric motors. The BSS is integral to the vessel's operational autonomy, providing consistent energy for continuous operation. A Hybrid Energy Storage System (HESS) composed of two or more battery packs with varying characteristics may be deployed to prevent battery oversizing. This system comprises cells with different technologies, specifically interconnected through distinctive Battery Management Systems (BMSs) and converters. This paper delves into the key challenges and optimization of HESS modular solutions, outlining the energy storage requirements and management strategies necessary for diverse vessel working cycles. Simulation results are presented to demonstrate the system's ability to supply a realistic 10-hour load cycle, even when starting from State of Charges (SOCs) unbalanced by over 30%. These findings illuminate the potential of HESS solutions in maintaining effective and sustainable electric propulsion in naval transport systems.The research leading to these results has received funding from the European Union under grant agreement No. 963560 Horizon 2020 SEABAT - "Solutions for largE bAtteries for waterBome trAnsporT". The authors would like to thank Mr. Simone Mongelli for the help with the simulations

Desarrollo de una vacuna inactivada contra la epidermitis exudativa porcina utilizando dos adyuvantes

Staphylococcus hyicus es el agente responsable de provocar la Epidermitis exudativa, una afección de la piel que afecta a los lechones lactantes y destetados menores de 6 semanas de edad. Esta patología se caracteriza por generar lesiones con exudación grasa, descamación y la formación de vesículas. A nivel global presenta una alta incidencia, con una variabilidad en la morbilidad del 20% al 100%, mientras que la mortalidad oscila entre el 50% y el 75%. En Argentina no se dispone actualmente de una vacuna que prevenga esta enfermedad, a pesar de que la inmunización se ha mostrado como una estrategia efectiva en la prevención de los procesos infecciosos en animales. Por lo tanto, el objetivo central de este estudio fue desarrollar dos bacterinas autógenas dirigidas contra Staphylococcus hyicus. Una de estas bacterinas se formuló utilizando un adyuvante convencional (hidróxido de aluminio), mientras que la otra utilizó el adyuvante inmunoestimulante (ISPA). La vacuna se empleó para inmunizar a cerdas preñadas, que fueron agrupadas según el adyuvante utilizado en la inmunización. La evaluación clínica se centró en determinar la tolerancia de las cerdas a las bacterinas. El resultado de esta evaluación fue exitoso, lo que marca un paso importante en la investigación y el desarrollo de medidas preventivas ante la Epidermitis exudativa

Long-Term Transplantation Outcomes in Patients With Primary Hyperoxaluria Type 1 Included in the European Hyperoxaluria Consortium (OxalEurope) Registry

INTRODUCTION: In primary hyperoxaluria type 1 (PH1), oxalate overproduction frequently causes kidney stones, nephrocalcinosis, and kidney failure. As PH1 is caused by a congenital liver enzyme defect, combined liver–kidney transplantation (CLKT) has been recommended in patients with kidney failure. Nevertheless, systematic analyses on long-term transplantation outcomes are scarce. The merits of a sequential over combined procedure regarding kidney graft survival remain unclear as is the place of isolated kidney transplantation (KT) for patients with vitamin B6-responsive genotypes. METHODS: We used the OxalEurope registry for retrospective analyses of patients with PH1 who underwent transplantation. Analyses of crude Kaplan–Meier survival curves and adjusted relative hazards from the Cox proportional hazards model were performed. RESULTS: A total of 267 patients with PH1 underwent transplantation between 1978 and 2019. Data of 244 patients (159 CLKTs, 48 isolated KTs, 37 sequential liver–KTs [SLKTs]) were eligible for comparative analyses. Comparing CLKTs with isolated KTs, adjusted mortality was similar in patients with B6-unresponsive genotypes but lower after isolated KT in patients with B6-responsive genotypes (adjusted hazard ratio 0.07, 95% CI: 0.01–0.75, P = 0.028). CLKT yielded higher adjusted event-free survival and death-censored kidney graft survival in patients with B6-unresponsive genotypes (P = 0.025, P < 0.001) but not in patients with B6-responsive genotypes (P = 0.145, P = 0.421). Outcomes for 159 combined procedures versus 37 sequential procedures were comparable. There were 12 patients who underwent pre-emptive liver transplantation (PLT) with poor outcomes. CONCLUSION: The CLKT or SLKT remains the preferred transplantation modality in patients with PH1 with B6-unresponsive genotypes, but isolated KT could be an alternative approach in patients with B6-responsive genotypes