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1 – 10 of 50Zhen 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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Shun Cai, Meng-Jia Jin, He Hao and Jian-Xin Shen
The purpose of this paper is to comparatively study a synchronous reluctance machine (SynRM) and a permanent magnet assisted synchronous reluctance machine (PMASynRM) as…
Abstract
Purpose
The purpose of this paper is to comparatively study a synchronous reluctance machine (SynRM) and a permanent magnet assisted synchronous reluctance machine (PMASynRM) as alternatives of the interior permanent magnet synchronous machine (IPMSM), and to investigate the performance and conclude both advantages and disadvantages.
Design/methodology/approach
A unified mathematical model is established for the IPMSM, SynRM and PMASynRM. Then finite element method (FEM) is used to compare the electromagnetic performance. Permeability-frozen method is utilized to distinguish basic electromagnetic torque and reluctance torque.
Findings
The PMASynRM can improve the power factor of the SynRM, overcome the drawback of the IPMSM in the high-speed flux-weakening region and is more proper to operate over a wide speed region. The SynRM is mechanically robust for lacking of the permanent magnets, and the PMASynRM can keep similar rotor stress as the SynRM by optimizing the magnets. Assembly of the SynRM is the simplest, and the economic performance of the SynRM and PMASynRM could be much better than the IPMSM which even uses ferrite magnets.
Practical/implications
The SynRM can produce identical torque and efficiency compared with the IPMSM except the poor power factor. The poor power factor could be improved by adopting the PMASynRM, which is proved to be able to act as an alternative of the IPMSM for low-cost high-performance application.
Originality/value
This paper provides the theoretical model of the IPMSM, SynRM and PMASynRM in a unified format. The electromagnetic, mechanical and economic performances of the three kinds of synchronous motors are compared comprehensively. Then, both the advantages and disadvantages are summarized.
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Ya Li, Xiping Liu and Zhangqi Liu
This paper aims to present an interior permanent magnet synchronous machine (IPMSM) with double-layer PMs used for electric vehicles, of which the integrated simulation of…
Abstract
Purpose
This paper aims to present an interior permanent magnet synchronous machine (IPMSM) with double-layer PMs used for electric vehicles, of which the integrated simulation of electromagnetic field, stress field and temperature field are analyzed.
Design/methodology/approach
Some electromagnetic characteristics including iron loss, efficiency and flux linkage are obtained by finite element analysis. The mechanical strength of rotor at the maximum speed and the temperature rise at the rated load are calculated by three-dimensional finite element analysis (FEA).
Findings
The results show that the presented IPMSM can work with sufficient mechanical strength, machine temperature rise and high efficiency during field-weakening operation. The experiments were carried out to verify the FEA, and acceptable results can be achieved.
Originality/value
This paper proposed a novel IPMSM with the double-layer permanent magnets, which is designed and checked by the multi-physics fields, and the high efficiency in all operational regions can be achieved for this machine.
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Jian‐Xin Shen, He Hao, Can‐Fei Wang and Meng‐Jia Jin
The aim of this paper is to present a new sensorless control strategy using a flux observer, which is particularly designed for taking into account the rotor saliency and winding…
Abstract
Purpose
The aim of this paper is to present a new sensorless control strategy using a flux observer, which is particularly designed for taking into account the rotor saliency and winding inductance variation in an interior permanent magnet synchronous motor (IPMSM).
Design/methodology/approach
In a PMSM, the magnets‐excited flux‐linkage, i.e. the rotor flux‐linkage, can be expressed as a vector. Its phase angle stands for the rotor position. Therefore, if this vector is estimated with an observer, the rotor position can be obtained without a position sensor, consequently, sensorless control can be realized. The main object of this paper is to establish and implement a model of rotor flux observer, specifically for IPMSM.
Findings
The flux observer model is built on the d‐q‐0 frame, using unequal values of the d‐axis inductance Ld and q‐axis inductance Lq to represent the IPMSM rotor saliency. Its digital implementation is proposed, whilst the sensorless control strategy is experimentally verified.
Research limitations/implications
Insignificant error exists in the estimated rotor position, probably due to the non‐sinusoidal variation of winding inductance. Further improvement of the observer model is preferable.
Originality/value
In previous works, the rotor flux observer is only applied to surface‐mounted permanent magnet synchronous motors (SPMSM) in which the winding inductance is constant. However, the proposed observer can deal with the rotor saliency and inductance variation in IPMSM, whilst its digital implementation is also new.
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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.
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Abbas Najjar-Khodabakhsh and Jafar Soltani
In this paper an adaptive nonlinear control scheme has been proposed for direct torque and flux control of interior permanent magnet synchronous motor (IPMSM) without using…
Abstract
Purpose
In this paper an adaptive nonlinear control scheme has been proposed for direct torque and flux control of interior permanent magnet synchronous motor (IPMSM) without using mechanical sensor.
Design/methodology/approach
In this control method the stator resistance is online estimated by adaptive input-output state feedback linearization (AIOFL) controller. Based on proposed control scheme, the strategies of the maximum torque per ampere (MTPA) and maximum power factor (MPF) have been tested using a so-called stator flux search method.
Findings
The motor equations are transferred from the stationary reference frame to the (SX-SY) two-axis frame of the current by the stator current angle. In this frame, the Y component of the motor current is set to zero and the implementation of the nonlinear controller is independent of the two-axis inductances, the rotor magnetic flux, and position.
Practical implications
The effectiveness and capability of the proposed control method has been verified by simulation and experimental results. The proposed control scheme can be used for the sensorless control of IPMSM drive in industrial applications such as electric vehicle, traction system, and air conditioner.
Originality/value
The proposed controller is developed in a special axis (X-Y) rotating reference frame with the X-axis in coincide with the machine current space vector so that there is no need to use and know the machine inductances and rotor position.
Ikhlas Bouzidi, Ahmed Masmoudi and Nicola Bianchi
This paper aims to the design and feature investigation of an interior permanent magnet synchronous machine (IPMSM) dedicated to propulsion applications.
Abstract
Purpose
This paper aims to the design and feature investigation of an interior permanent magnet synchronous machine (IPMSM) dedicated to propulsion applications.
Design/methodology/approach
The design approach as well as the performance investigation of the studied machine are based on a two‐dimensional finite element analysis. This latter is extended to a comparison study with other rotor topologies.
Findings
It has been found that the studied IPMSM offers higher performances than the usual PM machine topologies. This highlights the fact that the rotor design greatly affects the performance of PM machines.
Research limitations/implications
Many continuations of the developed works shall be treated in the future, such as: an optimization of the IPMSM design, an extension of the optimization to the machine‐inverter association, and a validation of the foreseen performance by experiments carried out on a prototype of the IPMSM.
Practical implications
The machine under study could be integrated in electric propulsion applications especially as a wheel‐mounted motor.
Originality/value
The paper treats the design and performance investigation of a new topology of IPM machines. It is a five‐phase concentrated winding synchronous machine with permanent magnet buried in an outer rotor.
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Yasuhito Takahashi, Koji Fujiwara and Takeshi Iwashita
This study aims to enhance the parallel performance of a parallel-in-space-and-time (PinST) finite-element method (FEM) using time step overlapping. The effectiveness of the…
Abstract
Purpose
This study aims to enhance the parallel performance of a parallel-in-space-and-time (PinST) finite-element method (FEM) using time step overlapping. The effectiveness of the developed method is clarified in a magnet eddy-current loss analysis of a practical interior permanent magnet synchronous motor (IPMSM) using a massively parallel computing environment.
Design/methodology/approach
The developed PinST FEM is a combination of the domain decomposition method as a parallel-in-space (PinS) method and a parallel time-periodic explicit error correction (PTP-EEC) method, which is one of the parallel-in-time (PinT) approaches. The parallel performance of the PinST FEM is further improved by overlapping the time steps with different processes in the PTP-EEC method.
Findings
By applying the overlapping PTP-EEC method, the convergence of the transient solution to its steady state can be accelerated drastically. Consequently, the good parallel performance of the PinST FEM is achieved in magnetic field analyses of the practical IPMSM using a massively parallel computing environment, in which over 10,000 processes are used.
Originality/value
In this study, the PinST FEM based on time step overlapping is newly developed and its effectiveness is demonstrated in a massively parallel computing environment, in which using either the PinS or PinT method alone cannot achieve sufficient parallel performance. This finding implies a new direction of parallel computing approaches for electromagnetic field computation.
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Bin Xia, Junmo Yeon and Chang Seop Koh
This paper aims to propose a numerically efficient multi-objective optimization strategy, which can improve both the efficiency and performance during the optimization process.
Abstract
Purpose
This paper aims to propose a numerically efficient multi-objective optimization strategy, which can improve both the efficiency and performance during the optimization process.
Design/methodology/approach
This paper discusses the multi-objective optimization algorithm by combining multi-objective differential evolution (MODE) algorithm with an adaptive dynamic Taylor Kriging (ADTK) model.
Findings
The proposed approach is validated through application to an analytic example and applied to a shape optimal design of a multi-layered interior permanent magnet synchronous motor for torque ripple reduction while maintaining the average torque.
Originality/value
The ADTK model selects its basis functions adaptively and dynamically so that it may have better accuracy than any other Kriging models. Through adaptive insertion of new sampling data, it guarantees minimum required sampling data for a desired fitting accuracy.
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Behrooz Majidi, Jafar Milimonfared and Kaveh Malekian
To optimize the performance of direct torque‐controlled interior permanent magnet synchronous motor drives, the purpose of this paper is to modify the constraints and strategies…
Abstract
Purpose
To optimize the performance of direct torque‐controlled interior permanent magnet synchronous motor drives, the purpose of this paper is to modify the constraints and strategies of such a control while accounting for magnetic saturation.
Design/methodology/approach
The machine model used to investigate the proposed method is the conventional two‐axis machine model, which is modified to include magnetic saturation in the quadrature axis. With the consideration of magnetic saturation, all optimal strategies, which correspond to the maximum torque per ampere and field weakening strategies, and motor‐inverter limitations are derived in T−|ψs| plane to apply in the direct torque control (DTC) method. Such strategies which take magnetic saturation into account and determine the optimal torque and flux commands are derived and implemented in DTC method.
Findings
Using the modified strategies ensures that the machine capacity is applied as much as possible. Simulation results emphasize the applicability and effectiveness of the proposed control process.
Research limitations/implications
In order to use the proposed method, it is necessary to define quadrature‐axis inductance as a function of quadrature‐axis current. Since, in this method, a simplified function is applied, it is not required to know exact magnetic behavior of motor and this simplified function can be easily obtained using finite element softwares.
Practical implications
Using the proposed method in practice results in better dynamic operation as well as maximal usage of the motor capacity.
Originality/value
This paper deals with consideration of magnetic saturation in DTC method which is not done in pervious works.
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