New Modulation Technique to Mitigate Common Mode Voltage Effects in Star-Connected Five-Phase AC Drives

Star-connected multiphase AC drives are being considered for electromovility applications such as electromechanical actuators (EMA), where high power density and fault tolerance is demanded. As for three-phase systems, common-mode voltage (CMV) is an issue for multiphase drives. CMV leads to shaft voltages between rotor and stator windings, generating bearing currents which accelerate bearing degradation and produce high electromagnetic interferences (EMI). CMV effects can be mitigated by using appropriate modulation techniques. Thus, this work proposes a new Hybrid PWM algorithm that effectively reduces CMV in five-phase AC electric drives, improving their reliability. All the mathematical background required to understand the proposal, i.e., vector transformations, vector sequences and calculation of analytical expressions for duty cycle determination are detailed. Additionally, practical details that simplify the implementation of the proposal in an FPGA are also included. This technique, HAZSL5M5-PWM, extends the linear range of the AZSL5M5-PWM modulation, providing a full linear range. Simulation results obtained in an accurate multiphase EMA model are provided, showing the validity of the proposed modulation approach.This work has been supported in part by the Government of the Basque Country within the fund for research groups of the Basque University system IT978-16 and in part by the Government of the Basque Country within the research program ELKARTEK as the project ENSOL (KK-2018/00040)

Control óptimo de par para máquinas SynRM aplicadas a vehículo eléctrico

Las máquinas de reluctancia síncrona asistidas por imanes están atrayendo un considerable interés como alternativa a las máquinas síncronas de imanes permanentes para su uso en sistemas de propulsión de vehículos eléctricos. El control óptimo de estas máquinas (incluyendo operación en debilitamiento de campo) puede resultar complejo, ya que estas son, por lo general, muy sensibles al fenómeno de la saturación magnética. En este artículo se trata su control, desde los reguladores hasta el precalculo de referencias de corriente óptimas para todo el rango de operación de la máquina. Finalmente, se muestran resultados experimentales obtenidos en una máquina de 51 kW.Postprint (published version

High-Voltage Stations for Electric Vehicle Fast-Charging: Trends, Standards, Charging Modes and Comparison of Unity Power-Factor Rectifiers

Emission of greenhouse gases and scarcity of fossil fuels have put the focus of the scientific community, industry and society on the electric vehicle (EV). In order to reduce CO2 emissions, cutting-edge policies and regulations are being imposed worldwide, where the use of EVs is being encouraged. In the best of scenarios reaching 245 million EVs by 2030 is expected. Extensive use of EV-s requires the installation of a wide grid of charging stations and it is very important to stablish the best charging power topology in terms of efficiency and impact in the grid. This paper presents a review of the most relevant issues in EV charging station power topologies. This review includes the impact of the battery technology, currently existing standards and proposals for power converters in the charging stations. In this review process, some disadvantages of current chargers have been identified, such as poor efficiency and power factor. To solve these limitations, five unidirectional three-phase rectifier topologies have been proposed for fast EV charging stations that enhance the current situation of chargers. Simulation results show that all the proposed topologies improve the power factor issue without penalizing efficiency. The topologies with the best overall performance are the Vienna 6-switch and the Vienna T-type rectifier. These two converters achieve high efficiency and power factor, and they allow a better distribution of losses among semiconductors, which significantly increase the life-cycle of the semiconductor devices and the reliability of the converter.This work was supported in part by the Government of the Basque Country through the Fund for Research Groups of the Basque University System under Grant IT978-16, in part by the Research Program ELKARTEK under Project ENSOL2-KK-2020/00077 and Project HARVESTGEN-KK-2020/00113, in part by the Ministerio de Ciencia e Innovacion of Spain under Project PID2020-115126RB-I00, and in part by the FEDER Funds. Documen

Normalised flux weakening control technique acting on the actual speed for automotive dual three-phase IPMSMs

Comunicación presentada en 6th IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC) Dates: 3/28/2023 - 3/31/2023 Venue: Arsenale di Venezia, Venice, ItalyIn this paper, a flux weakening control strategy based on a vector space decomposition (VSD) model is presented for asymmetrical dual threephase interior permanent magnet synchronous machines (IPMSMs). This strategy incorporates a voltage magnitude feedback loop, which provides robustness by adding a variation to the actual speed when enters in flux weakening mode or deviations occur in the electrical parameters of the machine. Validity of the proposal is demonstrated by simulation results carried out over standardised driving cycles, taking into account parameter mismatches.This work was supported in part by the Government of the Basque Country within the fund for research groups of the Basque University system IT1440-22 and by the MCIN/AEI/10.13039/501100011033 within the project PID2020-115126RB-I00

Sensorless control strategy for light-duty EVs and efficiency loss evaluation of high frequency injection under standardized urban driving cycles

Sensorless control of Electric Vehicle (EV) drives is considered to be an effective approach to improve system reliability and to reduce component costs. In this paper, relevant aspects relating to the sensorless operation of EVs are reported. As an initial contribution, a hybrid sensorless control algorithm is presented that is suitable for a variety of synchronous machines. The proposed method is simple to implement and its relatively low computational cost is a desirable feature for automotive microprocessors with limited computational capabilities. An experimental validation of the proposal is performed on a full-scale automotive grade platform housing a 51¿kW Permanent Magnet assisted Synchronous Reluctance Machine (PM-assisted SynRM). Due to the operational requirements of EVs, both the strategy presented in this paper and other hybrid sensorless control strategies rely on High Frequency Injection (HFI) techniques, to determine the rotor position at standstill and at low speeds. The introduction of additional high frequency perturbations increases the power losses, thereby reducing the overall efficiency of the drive. Hence, a second contribution of this work is a simulation platform for the characterization of power losses in both synchronous machines and a Voltage Source Inverters (VSI). Finally, as a third contribution and considering the central concerns of efficiency and autonomy in EV applications, the impact of power losses are analyzed. The operational requirements of High Frequency Injection (HFI) are experimentally obtained and, using state-of-the-art digital simulation, a detailed loss analysis is performed during real automotive driving cycles. Based on the results, practical considerations are presented in the conclusions relating to EV sensorless control.Peer ReviewedPostprint (published version

Next generation electric drives for HEV/EV propulsion systems: Technology, trends and challenges

In recent decades, several factors such as environmental protection, fossil fuel scarcity, climate change and pollution have driven the research and development of a more clean and sustainable transport. In this context, several agencies and associations, such as the European Union H2020, the United States Council for Automotive Research (USCAR) and the United Nations Economic and Social Commission for Asia (UN ESCAP) have defined a set of quantitative and qualitative goals in terms of efficiency, reliability, power losses, power density and economical costs to be met by next generation hybrid and full electric vehicle (HEV/EV) drive systems. As a consequence, the automotive electric drives (which consists of the electric machine, power converter and their cooling systems) of future vehicles have to overcome a number of technological challenges in order to comply with the aforementioned technical objectives. In this context, this paper presents, for each component of the electric drive, a comprehensive review of the state of the art, current technologies, future trends and enabling technologies that will make possible next generation HEV/EVs.This work has been partially supported by the Department of Education, Linguistic Policy and Culture of the Basque Government within the fund for research groups of the Basque university system IT978-16, by the Ministerio de Economía y Competitividad of Spain within the project DPI2014-53685-C2-2-R and FEDER funds and by the Government of the Basque Country within the research program ELKARTEK as the project KT4TRANS (KK-2015/00047 and KK-2016/00061), as well as by the program to support the specialization of Ph.D researchers at UPV/EHU ESPDOC16/25

Proposal of Hybrid Discontinuous PWM Technique for Five-Phase Inverters under Open-Phase Fault Operation

One of the most common issues in inverters are open-circuit faults (OPF). In this scenario, a proper fault-tolerant technique must be used to improve the motor performance. Although basic fault-tolerant modulation techniques are normally preferred, this paper proposes a discontinuous pulse-width modulation algorithm (HD-PWM) to operate five-phase inverters under a single OPF. In particular, loss equalization between the remaining switches after a fault occurs is the main objective of the HD-PWM algorithm, thus preventing future faults from occurring. The efficiency and harmonic distortion of the proposed technique are compared to the well-known sinusoidal PWM by simulation and experimentation under OPF conditions. The results obtained show a great performance of the proposed modulation technique, obtaining a relevant efficiency improvement.This work has been supported in part by the Government of the Basque Country within the fund for research groups of the Basque University system IT1440-22 and the MCIN/AEI/10.13039/501100011033 within the project PID2020-115126RB-I00

Comprehensive high speed automotive SM-PMSM torque control stability analysis including novel control approach

Permanent magnet synchronous machines (PMSM) are widely used in the automotive industry for electric vehicle (EV) and hybrid electric vehicle (HEV) propulsion systems, where the trend is to achieve high mechanical speeds. High speeds inevitably imply high current electrical frequencies, which can lead to a lack of controllability when using field oriented control (FOC) due to sampling period constraints. In this work, a comprehensive discrete-time model is fully developed to assess the stability issues in the widely used FOC. A speed-adaptive control structure that overcomes these stability problems and extends the speed operation range of the PMSM is presented. Also, a numerical methodology from which the maximum operating stable frequency can be computed in advance of any experimentation, is developed. All contributions are accompanied and supported by numerical results obtained from an accurate MATLAB/Simulink model.Peer ReviewedPostprint (published version

Potentzia-bihurgailu matriziala: teknologia eraginkor eta konpaktua

Gaur egun potentzia-elektronikaren erabilera oso hedatuta dago. Teknologia mota hau nonahi aurki daiteke: ibilgailu elektrikoetan, ur-ponpaketako sistemetan, hegazkinetan, haize-errotetan, etab. Potentzia-bihurgailuen artean, bihurgailu matriziala (MC, matrix converter) nabarmentzen da, honek azaltzen dituen ezaugarriak direla-bide. Bihurgailu horrek AC/AC bihurketa era zuzenean egiten du, eta hainbat aplikaziotan erabil daiteke, oso konpaktua eta eraginkorra baita. Gainera, bihurgailu horren bidez sintetizatutako seinaleen kalitatea oso ona da. Lan honetan, MCaren ezaugarriak, aplikazioak, erronkak, arkitektura eta modulazio-printzipioak azaltzen dira. Ondoren, adibide modura, bihurgailu hau haize-errota txikietan ezartzean lortzen diren emaitzak erakutsiko dira. Azkenik, Euskal Herriko Unibertsitatean eraikitako MC prototipo batean lortutako zenbait emaitza esperimentalen berri emango dugu, bihurgailuaren funtzionamendu erreala azaltzeko

A 3D Reduced Common Mode Voltage PWM Algorithm for a Five-Phase Six-Leg Inverter

Neutral point voltage control converters (NPVCC) are being considered for AC drive applications, where their additional degree of freedom can be used for different purposes, such as fault tolerance or common mode voltage (CMV) reduction. For every PWM-driven converter, the CMV is an issue that must be considered since it can lead to shaft voltages between rotor and stator windings, generating bearing currents that accelerate bearing degradation, and can also produce a high level of electromagnetic interference (EMI). In light of these considerations, in this paper a three-dimensional reduced common mode voltage PWM (3D RCMV-PWM) technique is proposed which effectively reduces CMV in five-phase six-leg NPVCCs. The mathematical description of both the converter and the modulation technique, in space-vector and carrier-based approaches, is included. Furthermore, the simulation and experimental analysis validate the CMV reduction capability in addition to the good behaviour in terms of the efficiency and harmonic distortion of the proposed RCMV-PWM algorithm.This work has been supported in part by the Government of Basque Country within the fund for research groups of the Basque University system IT1440-22 and MCIN/AEI/10.13039/ 501100011033 within the project PID2020-115126RB-I00