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1 – 10 of 77Ali Muhammad, Faisal Khan, Muhammad Yousuf and Basharat Ullah
The purpose of this paper is to modernize the generator system of wind turbine concept that not only improves the efficiency and power density but also reduces the system cost…
Abstract
Purpose
The purpose of this paper is to modernize the generator system of wind turbine concept that not only improves the efficiency and power density but also reduces the system cost making design simpler and less expensive, especially in large-scale production.
Design/methodology/approach
This paper presents a new permanent magnet transverse flux generator (PMTFG) for wind energy production. The key feature of its composition is the double armature coil in a semi-closed stator core. The main structural difference of the presented design is the use of double coil in the same space of semi-closed stator core and reduced number of stator pole pairs and rotor magnets from 12/24 to 10/20. 3D simulations are performed using finite element analysis (FEA) to measure induced voltage and magnetic field distribution at no load. The FEA is performed to quantify the change in flux linkage, induced voltage and output power as a function of different speeds and load current.
Findings
Results show that PMTFG with double coil configuration has improved electromagnetic performance in terms of flux linkage, induced voltage, output power and efficiency. The power density of 10/20 PMTFG with the double coil is 0.0524 KW/Kg, about an 18% increase compared to the conventional design.
Research limitations/implications
The proposed PMTFG is highly recommended for direct drive applications such as wind power.
Originality/value
Four models are simulated by FEA with single and double coil configuration, and load analysis is performed on all simulated models. Finally, results are compared with conventional PMTFG.
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Michal Cichowicz, Wojciech Pilecki, Marcin Wardach, Paweł Prajzendanc, Kamil Cierzniewski and Ryszard Palka
This paper aims to present the project of a permanent magnet synchronous machine which can be used as generator in the vertical axis wind turbine.
Abstract
Purpose
This paper aims to present the project of a permanent magnet synchronous machine which can be used as generator in the vertical axis wind turbine.
Design/methodology/approach
In the study, finite element analysis was used to perform simulation research of electrical machines. Based on the simulation studies, an experimental model was built. The paper presents also selected experimental results.
Findings
During the research, it was found that the radial arrangement of the permanent magnets is more favorable than the tangential one for the selected structure of the generator with permanent magnets.
Research limitations/implications
During the experimental research, a problem was encountered involving the correct control of the constructed generator at low rotational speeds.
Practical implications
The proposed solution can be used in low-speed vertical axis wind turbines.
Social implications
The presented research fits the global trend toward the use of alternative and renewable energy sources.
Originality/value
The paper presents new simulation studies of two low-speed generator topologies. The results for the radial and tangential arrangement of the permanent magnets in the rotor were verified. Based on this research, an experimental prototype of a generator for a slow-speed vertical axis wind turbine was built.
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Mohammadhossein Arianborna, Jawad Faiz, Mehrage Ghods and Amirhossein Erfani-Nik
The aim of this paper is to introduce an accurate asymmetric fault index for the diagnosis of the faulty linear permanent magnet Vernier machine (LPMVM).
Abstract
Purpose
The aim of this paper is to introduce an accurate asymmetric fault index for the diagnosis of the faulty linear permanent magnet Vernier machine (LPMVM).
Design/methodology/approach
Three-dimensional finite element method is applied to model the LPMVM. The geometrical and physical properties of the machine, the effect of stator and translator teeth, magnetic saturation of core and nonuniform air gap due to asymmetric fault are taken into account in the simulation. The air gap asymmetric fault is proposed. This analytical method estimates the air gap flux density of an LPMVM.
Findings
This paper presents an analytical method to predict the performance of a healthy and faulty LPMVM. The introduced index is based on the frequency patterns of the stator current. Besides, the robustness of the index in different loads and fault severity is addressed.
Originality/value
Introducing index for air gap asymmetry fault diagnosis of LPMVM.
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Keywords
Cheng Peng, He Cheng, Tong Zhang, Jing Wu, Fandi Lin and Jinglong Chu
This paper aims to further develop stator permanent magnet (PM) type memory machines by providing generalized design guidelines for double-stator memory machines (DSMMs) with…
Abstract
Purpose
This paper aims to further develop stator permanent magnet (PM) type memory machines by providing generalized design guidelines for double-stator memory machines (DSMMs) with hybrid PMs. This paper discusses the design experience of DSMMs and presents a comparative study of radial magnetization (RM) and circumferential magnetization (CM) types.
Design/methodology/approach
It begins with an introduction to RM and CM operating principles and magnetization mechanisms. Then, a comparative study is conducted for one of the RM-DSMM rotor pole pairs, inner and outer stator clamping angles and low coercive force PMs thickness. Finally, the two machines’ finite element simulation performance is compared. The validity of the proposed machine structure is demonstrated.
Findings
In this paper, the double-stator structure is extended to parallel hybrid PM memory machines, and two novel DSMMs with RM and CM configurations are proposed. Two types of DSMMs have PMs and magnetizing windings on the inner stator and armature windings on the outer stator. The main difference between the two is the arrangement of PMs on the inner stator.
Originality/value
Conventional stator PM memory machines have geometrical space conflicts between the PM and armature windings. The proposed double-stator structure can alleviate these conflicts and increase the torque density accordingly. In addition, this paper contributes to comparing the arrangement of hybrid PMs for DSMMs.
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Sumeet Khalid, Faisal Khan, Basharat Ullah, Zahoor Ahmad and Siddique Akbar
This paper aims to provide an overview of the recent developments and new topologies of single-phase moving magnet linear oscillating actuators (MMLOAs). The key advantage of the…
Abstract
Purpose
This paper aims to provide an overview of the recent developments and new topologies of single-phase moving magnet linear oscillating actuators (MMLOAs). The key advantage of the MMLOA when compared with conventional LOA is the absence of screws, gears and crankshaft mechanism, which results in fewer mechanical parts, simple structure, easy fabrication, lower noise levels and negligible frictional losses.
Design/methodology/approach
The review included papers up to August 2021. The structural designs of alternative topologies are deliberated in detail, and their relative merits and demerits are evaluated. Specific design issues, including pole and tooth number combinations, stroke length, magnet pole ratio and split ratio, are investigated. The imperative phenomena of the resonance, as well as the adjustable stroke, are also discussed in detail.
Findings
The electromagnetic performance in terms of thrust force of selected MMLOA topologies is compared. It is observed that the MMLOA with flux bridge topology has the highest thrust force of 365 N because of the large volume of the permanent magnets (PMs) used, which consequently increased the mass of the mover but based on overall performance analysis, single-phase end ferromagnetic Halbach surface-mounted PM LOA has the highest efficiency around 92%.
Originality/value
This review provides a comparative analysis for different tubular MMLOA topologies based on design construction and their electromagnetic performances.
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Zhen Sun, Takahiro Sato and Kota Watanabe
Topology optimization (TO) methods have shown their unique advantage in the innovative design of electric machines. However, when introducing the TO method to the rotor design of…
Abstract
Purpose
Topology optimization (TO) methods have shown their unique advantage in the innovative design of electric machines. However, when introducing the TO method to the rotor design of interior permanent magnet (PM) synchronous machines (IPMSMs), the layout parameters of the magnet cannot be synchronously optimized with the topology of the air barrier; the full design potential, thus, cannot be unlocked. The purpose of this paper is to develop a novel method in which the layout parameters PMs and the topology of air barriers can be optimized simultaneously for aiding the innovative design of IPMSMs.
Design/methodology/approach
This paper presents a simultaneous TO and parameter optimization (PO) method that is applicable to the innovative design of IPMSMs. In this method, the mesh deformation technique is introduced to make it possible to make a connection between the TO and PO, and the multimodal optimization problem can thereby be solved more efficiently because good topological features are inherited during iterative optimization.
Findings
The numerical results of two case studies show that the proposed method can find better Pareto fronts than the traditional TO method within comparable time-consuming. As the optimal design result, novel rotor structures with better torque profiles and higher reluctance torque are respectively found.
Originality/value
A method that can simultaneously optimize the topology and parameter variables for the design of IPMSMs is proposed. The numerical results show that the proposed method is useful and practical for the conceptual and innovative design of IPMSMs because it can automatically explore optimal rotor structures from the full design space without relying on the experience and knowledge of the engineer.
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Mohamed Amine Hebri, Abderrahmane Rebhaoui, Gregory Bauw, Jean-Philippe Lecointe, Stéphane Duchesne, Gianluca Zito, Abdelli Abdenour, Victor Mediavilla Santos, Vincent Mallard and Adrien Maier
The purpose of this paper is to exploit the optimal performances of each magnetic material in terms of low iron losses and high saturation flux density to improve the efficiency…
Abstract
Purpose
The purpose of this paper is to exploit the optimal performances of each magnetic material in terms of low iron losses and high saturation flux density to improve the efficiency and the power density of the selected motor.
Design/methodology/approach
This paper presents a study to improve the power density and efficiency of e-motors for electric traction applications with high operating speed. The studied machine is a yokeless-stator axial flux permanent magnet synchronous motor with a dual rotor. The methodology consists in using different magnetic materials for an optimal design of the stator and rotor magnetic circuits to improve the motor performance. The candidate magnetic materials, adapted to the constraints of e-mobility, are made of thin laminations of Si-Fe nonoriented grain electrical steel, Si-Fe grain-oriented electrical steel (GOES) and iron-cobalt Permendur electrical steel (Co-Fe).
Findings
The mixed GOES-Co-Fe structure allows to reach 10 kW/kg in rated power density and a high efficiency in city driving conditions. This structure allows to make the powertrain less energy consuming in the battery electric vehicles and to reduce CO2 emissions in hybrid electric vehicles.
Originality/value
The originality of this study lies in the improvement of both power density and efficiency of the electric motor in automotive application by using different magnetic materials through a multiobjective optimization.
Details
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Gerasimos G. Rigatos, Masoud Abbaszadeh, Fabrizio Marignetti and Pierluigi Siano
Voltage source inverter-fed permanent magnet synchronous motors (VSI-PMSMs) are widely used in industrial actuation and mechatronic systems in water pumping stations, as well as…
Abstract
Purpose
Voltage source inverter-fed permanent magnet synchronous motors (VSI-PMSMs) are widely used in industrial actuation and mechatronic systems in water pumping stations, as well as in the traction of transportation systems (such as electric vehicles and electric trains or ships with electric propulsion). The dynamic model of VSI-PMSMs is multivariable and exhibits complicated nonlinear dynamics. The inverters’ currents, which are generated through a pulsewidth modulation process, are used to control the stator currents of the PMSM, which in turn control the rotational speed of this electric machine. So far, several nonlinear control schemes for VSI-PMSMs have been developed, having as primary objectives the precise tracking of setpoints by the system’s state variables and robustness to parametric changes or external perturbations. However, little has been done for the solution of the associated nonlinear optimal control problem. The purpose of this study/paper is to provide a novel nonlinear optimal control method for VSI-fed three-phase PMSMs.
Design/methodology/approach
The present article proposes a nonlinear optimal control approach for VSI-PMSMs. The nonlinear dynamic model of VSI-PMSMs undergoes approximate linearization around a temporary operating point, which is recomputed at each iteration of the control method. This temporary operating point is defined by the present value of the voltage source inverter-fed PMSM state vector and by the last sampled value of the motor’s control input vector. The linearization relies on Taylor series expansion and the calculation of the system’s Jacobian matrices. For the approximately linearized model of the voltage source inverter-fed PMSM, an H-infinity feedback controller is designed. For the computation of the controller’s feedback gains, an algebraic Riccati equation is iteratively solved at each time-step of the control method. The global asymptotic stability properties of the control method are proven through Lyapunov analysis. Finally, to implement state estimation-based control for this system, the H-infinity Kalman filter is proposed as a state observer. The proposed control method achieves fast and accurate tracking of the reference setpoints of the VSI-fed PMSM under moderate variations of the control inputs.
Findings
The proposed H-infinity controller provides the solution to the optimal control problem for the VSI-PMSM system under model uncertainty and external perturbations. Actually, this controller represents a min–max differential game taking place between the control inputs, which try to minimize a cost function that contains a quadratic term of the state vector’s tracking error, the model uncertainty, and exogenous disturbance terms, which try to maximize this cost function. To select the feedback gains of the stabilizing feedback controller, an algebraic Riccati equation is repetitively solved at each time-step of the control algorithm. To analyze the stability properties of the control scheme, the Lyapunov method is used. It is proven that the VSI-PMSM loop has the H-infinity tracking performance property, which signifies robustness against model uncertainty and disturbances. Moreover, under moderate conditions, the global asymptotic stability properties of this control scheme are proven. The proposed control method achieves fast tracking of reference setpoints by the VSI-PMSM state variables, while keeping also moderate the variations of the control inputs. The latter property indicates that energy consumption by the VSI-PMSM control loop can be minimized.
Practical implications
The proposed nonlinear optimal control method for the VSI-PMSM system exhibits several advantages: Comparing to global linearization-based control methods, such as Lie algebra-based control or differential flatness theory-based control, the nonlinear optimal control scheme avoids complicated state variable transformations (diffeomorphisms). Besides, its control inputs are applied directly to the initial nonlinear model of the VSI-PMSM system, and thus inverse transformations and the related singularity problems are also avoided. Compared with backstepping control, the nonlinear optimal control scheme does not require the state-space description of the controlled system to be found in the triangular (backstepping integral) form. Compared with sliding-mode control, there is no need to define in an often intuitive manner the sliding surfaces of the controlled system. Finally, compared with local model-based control, the article’s nonlinear optimal control method avoids linearization around multiple operating points and does not need the solution of multiple Riccati equations or LMIs. As a result of this, the nonlinear optimal control method requires less computational effort.
Social implications
Voltage source inverter-fed permanent magnet synchronous motors (VSI-PMSMs) are widely used in industrial actuation and mechatronic systems in water pumping stations, as well as in the traction of transportation systems (such as electric vehicles and electric trains or ships with electric propulsion), The solution of the associated nonlinear control problem enables reliable and precise functioning of VSI-fd PMSMs. This in turn has a positive impact in all related industrial applications and in tasks of electric traction and propulsion where VSI-fed PMSMs are used. It is particularly important for electric transportation systems and for the wide use of electric vehicles as expected by green policies which aim at deploying electromotion and at achieving the Net Zero objective.
Originality/value
Unlike past approaches, in the new nonlinear optimal control method, linearization is performed around a temporary operating point, which is defined by the present value of the system’s state vector and by the last sampled value of the control input vector and not at points that belong to the desirable trajectory (setpoints). Besides, the Riccati equation, which is used for computing the feedback gains of the controller, is new, as is the global stability proof for this control method. Comparing with nonlinear model predictive control, which is a popular approach for treating the optimal control problem in industry, the new nonlinear optimal (H-infinity) control scheme is of proven global stability, and the convergence of its iterative search for the optimum does not depend on initial conditions and trials with multiple sets of controller parameters. It is also noteworthy that the nonlinear optimal control method is applicable to a wider class of dynamical systems than approaches based on the solution of state-dependent Riccati equations (SDRE). The SDRE approaches can be applied only to dynamical systems that can be transformed to the linear parameter varying form. Besides, the nonlinear optimal control method performs better than nonlinear optimal control schemes which use approximation of the solution of the Hamilton–Jacobi–Bellman equation by Galerkin series expansions.
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Mitja Garmut, Simon Steentjes and Martin Petrun
Small highly saturated interior permanent magnet- synchronous machines (IPMSMs) show a very nonlinear behaviour. Such machines are mostly controlled with a closed-loop cascade…
Abstract
Purpose
Small highly saturated interior permanent magnet- synchronous machines (IPMSMs) show a very nonlinear behaviour. Such machines are mostly controlled with a closed-loop cascade control, which is based on a d-q two-axis dynamic model with constant concentrated parameters to calculate the control parameters. This paper aims to present the identification of a complete current- and rotor position-dependent d-q dynamic model, which is derived by using a finite element method (FEM) simulation. The machine’s constant parameters are determined for an operation on the maximum torque per ampere (MTPA) curve. The obtained MTPA control performance was evaluated on the complete FEM-based nonlinear d-q model.
Design/methodology/approach
A FEM model was used to determine the nonlinear properties of the complete d-q dynamic model of the IPMSM. Furthermore, a fitting procedure based on the nonlinear MTPA curve is proposed to determine adequate constant parameters for MTPA operation of the IPMSM.
Findings
The current-dependent d-q dynamic model of the machine models the relevant dynamic behaviour of the complete current- and rotor position-dependent FEM-based d-q dynamic model. The most adequate control response was achieved while using the constant parameters fitted to the nonlinear MTPA curve by using the proposed method.
Originality/value
The effect on the motor’s steady-state and dynamic behaviour of differently complex d-q dynamic models was evaluated. A workflow to obtain constant set of parameters for the decoupled operation in the MTPA region was developed and their effect on the control response was analysed.
Details
Keywords
Salma Benharref, Vincent Lanfranchi, Daniel Depernet, Tahar Hamiti and Sara Bazhar
The purpose of this paper is to propose a new method that allows to compare the magnetic pressures of different pulse width modulation (PWM) strategies in a fast and efficient way.
Abstract
Purpose
The purpose of this paper is to propose a new method that allows to compare the magnetic pressures of different pulse width modulation (PWM) strategies in a fast and efficient way.
Design/methodology/approach
The voltage harmonics are determined using the double Fourier integral. As for current harmonics and waveforms, a new generic model based on the Park transformation and a dq model of the machine was established taking saturation into consideration. The obtained analytical waveforms are then injected into a finite element software to compute magnetic pressures using nodal forces.
Findings
The overall proposed method allows to accelerate the calculations and the comparison of different PWM strategies and operating points as an analytical model is used to generate current waveforms.
Originality/value
While the analytical expressions of voltage harmonics are already provided in the literature for the space vector pulse width modulation, they had to be calculated for the discontinuous pulse width modulation. In this paper, the obtained expressions are provided. For current harmonics, different models based on a linear and a nonlinear model of the machine are presented in the referenced papers; however, these models are not generic and are limited to the second range of harmonics (two times the switching frequency). A new generic model is then established and used in this paper after being validated experimentally. And finally, the direct injection of analytical current waveforms in a finite element software to perform any magnetic computation is very efficient.
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