High efficiency sensorless fault tolerant control of permanent magnet assisted synchronous reluctance motor

In the last decades, the development trends of high efficiency and compact electric drives on the motor side focused on Permanent Magnet Synchronous Machines (PMSMs) equipped with magnets based on the rare-earth elements. The permanent magnet components, however, dramatically impact the overall bill of materials of motor construction. This aspect has become even more critical due to the price instability of the rare-earth elements. This is why the Permanent Magnet Assisted Synchronous Reluctance Motor (PMaSynRM) concept was brought to the spotlight as it gives comparable torque density and similar efficiencies as PMSM although at a lower price accredited for the use of magnets built with ferrite composites. Despite these advantages, PMaSynRM drive design is much more challenging because of nonlinear inductances resulting from deep cross saturation effects. It is also true for multi-phase PMSM motors that have gained a lot of attention as they proportionally split power by the increased number of phases. Furthermore, they offer fault-tolerant operation while one or more phases are down due to machine, inverter, or sensor fault. The number of phases further increases the overall complexity for modeling and control design. It is clear then that a combination of multi-phase with PMaSynRM concept brings potential benefits but confronts standard modeling methods and drive development techniques. This Thesis consists of detailed modeling, control design, and implementation of a five-phase PMaSynRM drive for normal healthy and open phase fault-tolerant applications. Special emphasis is put on motor modeling that comprises saturation and space harmonics together with axial asymmetry introduced by rotor skewing. Control strategies focused on high efficiency are developed and the position estimation based on the observer technique is derived. The proposed models are validated through Finite Element Analysis (FEA) and experimental campaign. The results show the effectiveness of the elaborated algorithms and methods that are viable for further industrialization in PMaSynRM drives with fault-tolerant capabilities.En últimas décadas, las tendencias de desarrollo de accionamientos eléctricos compactos y de alta eficiencia en el lado del motor se centraron en las maquinas síncronas de imanes permanentes (PMSM) equipadas con imanes basados en elementos de tierras raras. Sin embargo, los componentes de imán permanente impactan dramáticamente en el coste de construcción del motor. Este aspecto se ha vuelto aún más crítico debido a la inestabilidad de precios de los elementos de tierras raras. Esta es la razón por la que el concepto de motor de reluctancia síncrona asistido por imán permanente (PMaSynRM) se ha tomado en consideración, ya que ofrece una densidad de par comparable y eficiencias similares a las de PMSM, aunque a un precio más bajo acreditado para el uso de imanes construidos con compuestos de ferritas. A pesar de drive PMaSynRM resulta muy complejo debido a las inductancias no lineales que resultan de los efectos de saturación cruzada profunda. Esto también es cierto para los motores PMSM polifásicos que han ganado mucha atención en los últimos años, en los que se divide proporcionalmente la potencia por el mayor número de fases. Además, ofrecen operación tolerante a fallas mientras una o más fases están inactivas debido a fallas en la máquina, el inversor o el sensor. Sin embargo, el número de fases aumenta aún más la complejidad general del diseño de modelado y control. Está claro entonces que una combinación de multifase con el concepto PMaSynRM tiene beneficios potenciales, pero dificulta los métodos de modelado estándar y las técnicas de desarrollo del sistema de accionamiento. Esta tesis consiste en el modelado detallado, el diseño de control y la implementación de un drive PMaSynRM de cinco fases para aplicaciones normales en buen estado y tolerantes a fallas de fase abierta. Se pone especial énfasis en el modelado del motor que comprende la saturación y los armónicos espaciales junto con la asimetría axial introducida por la inclinación del rotor. Se desarrollan estrategias de control enfocadas a la alta eficiencia y se deriva la estimación de posición basada en la técnica del observador. Los modelos propuestos se validan mediante Análisis de Elementos Finitos (FEA) y resultados experimentales. Los resultados muestran la efectividad de los algoritmos y métodos elaborados, que resultan viables para la industrialización de unidades PMaSynRM con capacidades tolerantes a fallas.Postprint (published version

Multiphase PMSM and PMaSynRM flux map model with space harmonics and multiple plane cross harmonic saturation

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Multiphase Synchronous Machines vary in rotor construction and winding distribution leading to non-sinusoidal inductances along the rotor periphery. Moreover, saturation and cross-saturation effects make the precise modeling a complex task. This paper proposes a general model of multi-phase magnet-excited synchronous machines considering multi-dimensional space modeling and revealing cross-harmonic saturation. The models can predict multiphase motor behavior in any transient state, including startup. They are based on flux maps obtained from static 2D Finite-Element (FE) analysis. FE validations have been performed to confirm authenticity of the dynamic models of multiphase PMaSynRMs. Very close to FE precision is guaranteed while computation time is incomparably lower.Postprint (author's final draft

Healthy and open phase PMaSynRM model based on virtual reluctance concept

© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The trend in the industrial power electronics electrical drives is to reach high power density and high efficiency in variable load conditions at cost-effective unwasteful designs. Currently, motors with permanent magnets (such as IPMSM and PMaSynRM) are of great interest because of compactness, low losses, and high torque capability. The performance of a drive system can be predicted with a motor electromagnetic authentic nonlinear model. In this paper, a novel, fast, and precise motor model of PMaSynRM based on virtual reluctance (VR) is proposed. It takes into account the cross saturation, winding distribution, space harmonics, slotting effect, and stepped skewing. The virtual reluctances are identified by finite element analysis (FEA) and implemented in the time-stepping simulation. The flux inversion is not required. The proposed concept is useful in the rotating field or phase quantities (for open phase simulation). The model is also discretized for SiL and HiL applications. Finally, the validation in FEA and experimental setup was performed.This work was supported in part by Spanish Ministry of Economy and Competitiveness under TRA2016-80472-R Research Project and Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya under 2017SGR967.Peer ReviewedPostprint (author's final draft

A Versatile workbench simulator: Five-phase inverter and PMa-SynRM performance evaluation

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Thispaperpresents the design and structure of aversatileworkbench simulator forevaluating the performance of a five-phase inverter andPermanent Magnet assisted Synchronous Reluctance Motor(PMa-SynRM). The simulatorallows for adding variations tothe modulationtechniques, changingthe inverter structure’s semiconductordevice, and calculatingtheinverter’spower losses. Itcanalso facilitate observingthe current, voltage,andthe jointtemperature ofthe semiconductors devices. Furthermore,wecanobtain a perform that is close to anactualPMa-SynRM, dependingon the desired conditionsof speed and torque. The workbench simulator wasdevelopedby combining three software: Matlab/Simulink, PLECSand Altair Flux.Postprint (author's final draft

Magnetic skew interface in five-phase ferrite assisted synchronous reluctance motor model

© 2021 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Permanent Magnet Assisted Five-Phase Synchronous Machine is analytically modeled in the rotating (dq1dq3) reference frames. The cross saturation and space harmonics are captured in the magnetic flux maps obtained from static 2D finite element (FE) analysis. In this paper, a method to incorporate the skewing effect in the flux map distribution for the first and third harmonic is presented. The original flux for one motor segment is used to calculate fluxes of the first and third planes in the consecutive skewing segments. Respective rotator operators allow to sum the contribution from axial slice and shift the resulting map to the desired zero reference position. Eventually, a dynamic model is established on the new corrected flux maps. FE and experimental validations have been performed to confirm the authenticity of the proposed technique.Peer ReviewedPostprint (author's final draft

Rotor of synchronous reluctance motor optimization by means reluctance network and genetic algorithm

An optimal design for a rotor of SynRM is proposed on this paper. The inductances of the machine computed in dq-axes allow determining machine performance and the motor behavior. High magnetic saturation on this kind of motor increases the difficulty of inductance calculation. Hence, the finite element analysis is currently used to design and optimize SynRM, from the first instance. This method usually requires a high amount of computational time and resources. For this reason, the reluctance network here proposed is a good alternative to consider for designing these motors, because it is a fast and good method to obtain the inductances of the SynRM. Therefore, an optimal design avoiding FEA is proposed on this paper using the reluctance network to calculate the dq-axes motor inductances.Postprint (published version

Vector control of crosswise saturating five-phase PMaSynRM in wide speed range

This paper deals with the realization of a five-phase cross saturating permanent magnet assisted synchronous reluctance motor (PMaSynRM) drive with vector control based on maximum torque per ampere (MTPA) and flux weakening (FW) control strategies derived from the identified flux maps originating from the finite element analysis (FEM). Tracking of the reference currents in dq1 and dq3 axes is guaranteed with the proposed approach and the voltage and current constraints are not exceeded at any working condition.Peer ReviewedPostprint (author's final draft

Rotor of synchronous reluctance motor optimization by means reluctance network and genetic algorithm

An optimal design for a rotor of SynRM is proposed on this paper. The inductances of the machine computed in dq-axes allow determining machine performance and the motor behavior. High magnetic saturation on this kind of motor increases the difficulty of inductance calculation. Hence, the finite element analysis is currently used to design and optimize SynRM, from the first instance. This method usually requires a high amount of computational time and resources. For this reason, the reluctance network here proposed is a good alternative to consider for designing these motors, because it is a fast and good method to obtain the inductances of the SynRM. Therefore, an optimal design avoiding FEA is proposed on this paper using the reluctance network to calculate the dq-axes motor inductances