A segmented rotor type switched reluctance machine for BSGs of hybrid electric vehicles: Concept, design and analysis

© 2017 IEEE. This paper proposes a novel 16/10 segmented rotor switched reluctance machine (SSRM) for belt-driven starter generators (BSGs) of hybrid electric vehicles. The stator of proposed SSRM consists of two types of stator poles: exciting pole and auxiliary pole, and the rotor of proposed SSRM is made up of a series of discrete segments. Firstly, the concept of the conventional SRM and proposed machine is presented. Secondly, the design rules of proposed SSRM are described. Finally, the finite element method (FEM) is employed to get the static characteristics of the proposed SSRM, including the magnetic flux distribution, magnetic flux density, inductance characteristic, torque characteristic and continuous torque. Result shows that the torque ripple of proposed SSRM is low

Comparison of torque characteristics for a novel segmented and a conventional switched reluctance motors

© 2017 IEEE. The extensive applications of switched reluctance motor (SRM) have been limited due to its drawback of torque ripple. Thus, the reduction of torque ripple is an important problem in studying the SRM. A novel 16/10 segmented SRM (SSRM) is proposed in this paper. The proposed SSRM performs well in terms of torque ripple and tolerant-fault characteristic. The stator of the proposed structure is constructed from exciting and auxiliary stator poles, while the rotor consists of a series of discrete segments. Moreover, the torque ripple is evaluated by comparing with the conventional 8/6 SRM. Finally, the tolerant-fault characteristic of the proposed SSRM and conventional SRM are compared as well. The finite element method (FEM) is employed to demonstrate the prominent advantages of static and dynamic characteristics of the proposed SSRM

Modeling and operation of a bearingless fixed-pole rotor induction motor

© 2002-2011 IEEE. The rotor currents are induced by both suspension force winding magnetic field and torque winding magnetic field in the traditional bearingless induction motors (BIMs). Due to the currents induced by the suspension force winding, there are errors in the generation of radial suspension forces. To address such problems, a novel BIM with fixed-pole rotor, called bearingless fixed-pole rotor induction (BFPRI) motor is proposed. The structure of BFPRI motor is first analyzed and the mathematical models of radial suspension forces are deduced. Based on the finite element analysis, the induced currents and radial suspension forces are also investigated and compared with the traditional BIM. Finally, the prototype motor is built and experimental research is carried out. In this novel motor, only the torque winding magnetic field induces currents in the rotor, which makes the precision of radial suspension forces higher and thereby reduces the complexity of BIM control system. The effectiveness of the proposed BFPRI motor is validated by both simulation and experiments

Performance analysis of suspension force and torque in an IBPMSM with V-Shaped PMs for flywheel batteries

© 1965-2012 IEEE. Due to the advantages such as high energy density, high power density, high cyclic life, and environmentally friendly, the flywheel battery has the potential to solve the problem of energy storage. In order to improve the torque density and suspension performance of bearingless synchronous permanent magnet (PM) synchronous motors (BPMSMs), a novel rotor structure with V-shaped PMs is designed in this paper. Furthermore, the interior BPMSM (IBPMSM) with V-shaped PM which used for flywheel batteries of electric vehicles is researched in detail. Especially, the influence of geometrical parameters of V-shaped PM on suspension force and electromagnetic torque is investigated. Moreover, the corresponding static electrical magnetic characteristics including inductances and electromagnetic torque are also studied. The finite-element method is employed to evaluate the theoretical analysis of the proposed IBPMSM. In addition, the optimized motor is validated to have good suspension performance by some experiments

Rotary Switched Reluctance Actuator: A Review On Design Optimization And Its Control Methods

A switched reluctance actuator (SRA) is a type of electromagnetic stepper actuator that is gaining popularity for its simple and rugged construction, ability of extremely high-speed operation and hazard-free operation. SRA gained supremacy over permanent magnet actuators due to the fact that its building material are relatively low cost compared to the expensive and rare permanent magnets. SRA is already making its debut in automotive, medical and high precision applications. However, many parties are still oblivious to this new age actuator. This paper reviews the latest literature in terms of journal articles and conference proceedings regarding the different design parameters and control method of SRA. The impact of the parameters on the performance of SRA are discussed in details to provide valuable insight. This paper also discussed the advantages of various novel SRA structure designs that prove to be a huge contribution to the future technology. It is found that several design parameters such as the air gap when kept minimum, increases torque value; while increasing number of phases in SRA minimizes torque ripples. Increased stator and rotor arc angles will increase torque, not to mention a larger excitation current can also achieve the same effect. Researches are often done through Finite Element Method (FEM) analysis to verify the optimized design parameters before fabrication, whilst experimental procedures are executed to verify the simulation results. To ensure smooth phase switching and improved torque output, intelligent controllers are employed in speed control and direct torque control (DTC) methods of SRA

Decoupling Control for Dual-Winding Bearingless Switched Reluctance Motor Based on Improved Inverse System Method

Dual-winding bearingless switched reluctance motor (BSRM) is a multivariable high-nonlinear system characterized by strong coupling, and it is not completely reversible. In this paper, a new decoupling control strategy based on improved inverse system method is proposed. Robust servo regulator is adopted for the decoupled plants to guarantee control performances and robustness. A phase dynamic compensation filter is also designed to improve system stability at high-speed. In order to explain the advantages of the proposed method, traditional methods are compared. The tracking and decoupling characteristics as well as disturbance rejection and robustness are deeply analyzed. Simulation and experiments results show that the decoupling control of dual-winding BSRM in both reversible and irreversible domains can be successfully resolved with the improved inverse system method. The stability and robustness problems induced by inverse controller can be effectively solved by introducing robust servo regulator and dynamic compensation filter

Critical Review of Flywheel Energy Storage System

This review presents a detailed summary of the latest technologies used in flywheel energy storage systems (FESS). This paper covers the types of technologies and systems employed within FESS, the range of materials used in the production of FESS, and the reasons for the use of these materials. Furthermore, this paper provides an overview of the types of uses of FESS, covering vehicles and the transport industry, grid leveling and power storage for domestic and industrial electricity providers, their use in motorsport, and applications for space, satellites, and spacecraft. Different types of machines for flywheel energy storage systems are also discussed. This serves to analyse which implementations reduce the cost of permanent magnet synchronous machines. As well as this, further investigations need to be carried out to determine the ideal temperature range of operation. Induction machines are currently stoutly designed with lower manufacturing cost, making them unsuitable for high-speed operations. Brushless direct current machines, the Homolar machines, and permanent magnet synchronous machines should also be considered for future research activities to improve their performance in a flywheel energy storage system. An active magnetic bearing can also be used alongside mechanical bearings to reduce the control systems’ complications, thereby making the entire system cost-effective

Torque Analysis and Dynamic Performance Improvement of a PMSM for EVs by Skew Angle Optimization

© 2018 IEEE. In this paper, a permanent magnet synchronous machine (PMSM) for electric vehicles (EVs) is studied. Since EVs need to face some low speed road conditions, it is necessary to drive the machine to maintain a stable torque at low speed. The stator skew slot is often adopted to reduce torque ripple; however, it declines the output torque at same time. Besides, the difference between positive rotation performance and negative rotation performance, which caused by the skew slot are often ignored. Through the finite element analysis, the cogging torque and dynamic performance of the PMSM at different skew angle are studied. Moreover, the different influence of slot skew angle on positive and negative rotation performance is studied. Then, the optimum skew angle of the PMSM is studied through comprehensive consideration. Finally, the cogging torque of the prototype is verified to be less than 2 N·m through the experiment

Advanced control strategies for partially levitating multi-sector permanent magnet synchronous machines

The thesis presents solutions to improve the performance of a partially levitating bearingless permanent magnet synchronous machine with a multi-three-phase winding. A combined winding topology, which consists of three independent three-phase sub-windings, is installed in the stator where each phase contributes to both the suspension force and the motoring torque. This work focuses on control algorithms, including fault-tolerant controls, a current limitation technique, and a current-sharing technique. Firstly, the thesis presents an analytical formulation of the force and torque generation in healthy operative conditions. Following, the three-phase and single-phase open-circuit fault conditions are also analysed. The analytical model of the machine is presented in a generic matrix form so that it can be applied to any machine with a multi-three-phase winding structure if the coupling among sectors is negligible. The fault-tolerant control algorithms address the issues of open-circuit faults of an entire three-phase sub-winding, of a single-phase in a three-phase sub-winding, or of two phases belonging to two different three-phase sub-windings. The theoretical analysis is verified with both Finite Elements Analysis and experimental tests. Then, the thesis proposes a current limitation technique. The main challenges with the combined winding configuration consist of decoupling the suspension force and torque generation and designing a proper current limitation technique. The latter is required in order to maintain the machine in safe operative conditions according to its current-voltage rating and its operative thermal limits. This thesis addresses the limitation technique based on the analytical models, considering both healthy and faulty conditions. In particular, the proposed current limitation technique allows prioritising the suspension force, which is considered a safety-critical output with respect to the torque in order to avoid the rotor touchdown. Numerical simulation results and experimental validation are provided to validate the algorithm. Finally, the thesis proposes a modular approach for a current-sharing control of the machine. A thorough explanation of the methodology used is presented, as well as control algorithms to consider the torque and force control combined with the current-sharing management of the machine. Particular emphasis is also placed on validating the modelling hypotheses based on a finite element characterisation of the machine electro-mechanical behaviour. The proposed control strategy is also extended to cater to the possibility of one or more inverters failure, thus validating the intrinsic advantage of the redundancy obtained by the system's modularity. An extensive experimental test is finally carried out on a prototyped machine. The obtained results validate the current-sharing operation in either healthy or faulty scenarios, both at steady-state and under transient conditions. These outcomes show the potential of the proposed strategy to increase the versatility of fault-tolerant drives applied to this machine topology

Aktiivinen magneettilaakeri vaihtoreluktanssimoottorina

The goal of this work was to research the similarities between active magnetic bearings and switched reluctance motor and particularly research the chances for converting magnetic bearing into switched reluctance motor. In addition, ways to cope with the widely reported problems the motor type has were studied. The test environment consisted of test rig, previously used for testing control methods for magnetic bearing. In addition to this, MATLAB Simulink simulation models were built to help the designing of the test setup. The test setup had two alternative controllers, an original magnetic bearing controller, modified to work as a motor controller and a new CompactRIO-based controller that was used for comparing different speed control and commutation methods. New rotor designs were engineered to work with the prototype motor that used unmodified magnetic bearing stator. This setup was tested for obtaining the output torque and maximum speed of the motor together with the accuracy to follow set values. Test results of simulations and test setup were inside the error margins, showing the use of simulations beneficial in design process of this type of a motor. The tests revealed differences between the control methods, suggesting using the advanced angle controller and adjustable commutation angles.Työn tavoitteena oli tutkia yhteneväisyyksiä aktiivimagneettilaakerien ja vaihtoreluktanssimoottorin välillä. Tutkimus keskittyi erityisesti arvioimaan mahdollisuuksia muuntaa magneettilaakeri vaihtoreluktanssimoottoriksi. Lisäksi tutkittiin keinoja ratkaista ongelmia, joita tämän tyyppisessä sähkömoottorissa on raportoitu olevan. Testiympäristö koostui roottorikoelaitteesta, jota on aikaisemmin käytetty magneettilaakerin säätöjärjestelmän tutkimuksessa. Lisäksi rakennettiin MATLAB Simulink simulointimalli, jota käytettiin moottorin säätöjärjestelmän suunnittelun apuna. Testilaitteessa oli kaksi vaihtoehtoista säätöjärjestelmää; alkuperäinen magneettilaakerin ohjain muokattuna toimimaan moottorin ohjaimena sekä uusi CompactRIO -järjestelmään perustuva säätöjärjestelmä. Jälkimmäistä käytettiin erilaisten nopeus- ja kommutointitapojen vertailuun keskenään. Prototyyppimoottorin staattori oli sama, jota käytettiin magneettilaakerin kanssa. Roottori suunniteltiin sopimaan juuri tähän käyttötarkoitukseen. Tätä koelaitetta testattiin vääntömomentin ja maksiminopeuden selvittämiseksi. Lisäksi suoritettiin testejä, joissa tutkittiin kykyä seurata nopeuden asetusarvoa. Simuloimalla saadut tulokset olivat hyvin lähellä koelaitteella saatuja tuloksia osoittaen simuloinnin käytön olevan hyödyllistä tämän tyyppisen moottorin suunnittelussa. Säätömenetelmät suoriutuivat vaihtelevalla menestyksellä testeistä. Suositeltava säätömenetelmä oli edistyskulman säädin, joka käytti hyväkseen säädettäviä kommutointikulmia