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The driving speed of pure electric vehicles changes frequently under complex driving conditions, and there is no mathematical law to follow. Poor working conditions will lead to varying driving motor parameters. Traditional motor control PI regulator parameters are fixed and cannot be adjusted in real time following the vehicle driving state. The dynamic performance of the drive system decreases due to the increase of AC/DC coupling in the high-speed field weakening region of the interior permanent magnet synchronous motor (IPMSM). To solve the above problems, an IPMSM fuzzy single-current field weakening control algorithm for pure electric vehicles was proposed, and the parameters of the PI regulator were adjusted in real time through fuzzy control to enhance the response characteristics and anti-interference characteristics of the drive system. The optimized single-current field weakening control method was adopted, and the a-axis and d-axis voltage was adjusted in real time based on the vehicle speed and the output torque, which enhanced the control performance of the vehicle in the high-speed field weakening region. The feasibility and effectiveness of the proposed control algorithm were verified through a simulation comparison with the traditional PI-adjusted single-current field weakening control algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes a method for compensation of dead-time effects for a fivephase inverter. In the proposed method an additional control subsystem was added to the field-oriented control (FOC) scheme in the coordinate system mapped to the third harmonic. The additional control loop operates in the fixed, orthogonal reference frame (α - β coordinates) without the need for additional Park transformations. The purpose of this method is to minimize the dead-time effects by third harmonic injection in two modes of operation of the FOC control system: with sinusoidal supply and with trapezoidal supply. The effectiveness of the proposed control method was verified experimentally on a laboratory setup with a prototype five-phase interior permanent magnet synchronous machine (IPMSM). All experimental results were presented and discussed in the following paper. [ABSTRACT FROM AUTHOR]

An interior permanent magnet synchronous motor (IPMSM) is characterized by its high efficiency. However, torque ripple and loss occur because of the spatial harmonics generated by air‐gap permeance fluctuations. This study clarified that slot harmonic components can be suppressed by inserting magnetic wedges made of magnetic composite material in the slot opening of an IPMSM. First, the authors examined the torque and loss characteristics by varying relative permeability and saturation magnetic flux density of magnetic wedges using finite element analysis (FEA). Results indicated that the torque ripple and loss could be suppressed when the relative permeability of the magnetic wedge was μr = 10 to 22 and the saturation magnetic flux density was Bs = 0.5 to 0.75 T. Furthermore, the authors produced magnetic composite materials made of various soft magnetic material powders and examined their magnetic properties and viscosities. Results showed that a magnetic composite material with optimal magnetic properties and injectable viscosity could be manufactured using Fe‐Si‐Al with a low volume fraction. [ABSTRACT FROM AUTHOR]

Interior permanent-magnet synchronous machines (IPMSMs) are widely used as traction motors in electric drive-trains because of their high torque-per-ampere characteristics and potential for wide field-weakening operations to expand the constant-power range. This paper offers a categorization and a comprehensive overview of the control techniques applied to IPMSM drives in addition to presenting the necessary theoretical background. The basic concept, features and limitations, as well as the latest developments of the strategies, are summarized in the paper. This overview helps to lay the theoretical basis as well as to clarify the opportunities, challenges and future trends for controlling IPMSM drives for traction applications. [ABSTRACT FROM AUTHOR]

When a permanent magnet synchronous motor (PMSM) is designed according to the traditional motor design theory, the performance of the motor is often challenging to achieve the desired goal, and further optimization of the motor design parameters is usually required. However, the motor is a strongly coupled, non-linear, multivariate complex system, and it is a challenge to optimize the motor by traditional optimization methods. It needs to rely on reliable surrogate models and optimization algorithms to improve the performance of the PMSM, which is one of the problematic aspects of motor optimization. Therefore, this paper proposes a strategy based on a combination of a high-precision combined surrogate model and the optimization method to optimize the stator and rotor structures of interior PMSM (IPMSM). First, the variables were classified into two layers with high and low sensitivity based on the comprehensive parameter sensitivity analysis. Then, Latin hypercube sampling (LHS) is used to obtain sample points for highly sensitive variables, and various methods are employed to construct surrogate models for variables. Each optimization target is based on the acquired sample points, from which the most accurate combined surrogate model is selected and combined with non-dominated ranking genetic algorithm-II (NSGA-II) to find the best. After optimizing the high-sensitivity variables, a new finite element model (FEM) is built, and the Taguchi method is used to optimize the low-sensitivity variables. Finally, finite element analysis (FEA) was adopted to compare the performance of the initial model and the optimized ones of the IPMSM. The results showed that the performance of the optimized motor is improved to prove the effectiveness and reliability of the proposed method. [ABSTRACT FROM AUTHOR]

A surface-mounted permanent magnet synchronous motor (SPMSM) is an electric motor with a simple magnetic circuit design, fast responsiveness, linear torque–current characteristics, speed–voltage characteristics, and constant operating speed. SPMSMs use only magnetic torque; however, interior PMSMs (IPMSMs) have high power densities because they can use reluctance torque. In addition, when flux-weakening control is used, the operating range is wide compared with the SPMSM. This study presents a comparative analysis of the characteristics of SPMSM and bar-type IPMSM. Characteristic analyses are performed by setting the same stator shape, rated speed, number of turns, winding specifications, voltage limit, and magnet usage in a pole/slot combination of six poles and 27 slots. Next, we compare the no-load back electromotive force, cogging torque, and loss characteristics, and perform a characteristic analysis of each model while satisfying the design specifications. No-load and load tests are performed using a back-to-back system. The results of the analysis and experimental results are in good agreement, and the reliability of the analysis results is guaranteed. The SPMSM is approximately 8.5% superior to the IPMSM in terms of core loss, and the eddy current loss is greater than that of the IPMSM. [ABSTRACT FROM AUTHOR]

To solve the optimization issues of interior permanent magnet synchronous motors (IPMSMs) and ensure a large output torque while minimizing torque ripple and core loss, the multi-objective optimization strategy should be employed. In this study, we took an 8-pole, 48-slot IPMSM as a specimen. First, the width and thickness of the permanent magnet (PM) and the rotor bridge structures were pre-selected as optimization parameters, while torque ripple and core loss were taken as optimization targets. Then, the Taguchi method to perform orthogonal experiments was employed to select the multi-parameter combinations that make the experimental results stable and with little fluctuation. To ensure the optimal results, the function equations were obtained by multivariate nonlinear fitting, while the parameters were optimized by particle swarm optimization (PSO). Finally, the optimal results were verified by the Finite Element Method (FEM). The results show that our proposed hybrid method can provide an optimal design strategy with better performance such as smaller torque ripple and core loss while maintaining a larger output torque. [ABSTRACT FROM AUTHOR]

This study presents an algorithm for estimating two-phase rotor reference frame currents using a single-current sensor. For proper vector control operation, at least two of three-phase current information is required. The single-current sensor algorithm is presented for vector-controlled interior permanent magnet synchronous motor drive to reduce the cost and increase reliability. dq-axes current formation method evaluates the two-phase currents in the stationary reference frame by sensing only one-phase current and speed/position information. The two-phase stationary reference frame currents, iβs current, are estimated using iqs* and iαs, i.e., constructed from single sensor information. D- and q-axes currents are obtained from i αs and is β*. These are used to close the current loop in the vector-controlled drive. Three- phase currents can be reconstructed from the estimated two-phase currents. This method is entirely independent of machine parameters and applicable to all kinds of permanent magnet synchronous motor machines. The presented algorithm is validated on MATLAB/SIMULINK platform. Some sample results are shown from an experiment performed on a prototype developed in the laboratory (using dSPACE 1104). [ABSTRACT FROM AUTHOR]

As asymmetric interior permanent magnet synchronous motor (AIPMSM) has excellent performance but complicated topological structure, a novel high-resolution encoding and edge smoothing method is proposed for topology optimization of the asymmetric rotor of interior permanent magnet synchronous motor (IPMSM) in this study. This method aims to solve complex electromagnetic design problems with time-dependent performance through a multi-objective genetic algorithm (MOGA) integrated with a high-resolution encoding and edge smoothing method. The complex structure is represented by a high-resolution image-like matrix and then vectorized by the edge smoothing method. Therefore, the commonly used discrete binary encoded variables related to the finite element (FE) model are replaced with a vectorized topological structure and other control variables. In this sense, high-resolution matrix and edge smoothing methods are used for the first time to represent the rotor topology of AIPMSMs. Compared with the traditional topology optimization method, the proposed method has the advantage of expressing more complex and vectorized topological structures; meanwhile, the obtained performance is accurate and trustworthy using conventional FE simulation. Numerical results show that a stable convergence is achieved with the avoidance of checkerboards and material overlapping. It is shown that the proposed method can find solutions with better performances, in comparison with the reference model. [ABSTRACT FROM AUTHOR]

This paper proposes a traction unit that combines an interior permanent magnet motor and a PM-assisted synchronous reluctance motor for electric vehicles to improve traction performance, enhance energy efficiency, and reduce cost. The characteristics of three traction units are analyzed and compared, including (a) rear-wheel-drive configuration using one IPM motor; (b) all-wheel-drive configuration using two interior permanent magnet motors; and (c) all-wheel-drive with a combination of one interior permanent magnet motor and one PM-assisted synchronous reluctance as proposed in this paper. The operational characteristics of each motor to achieve a wide constant power speed range are first investigated. Then, the Urban Dynamometer Driving Schedule is utilized to compare and evaluate the operational characteristics, energy consumption, and most importantly, the efficiency of the traction units. Simulation results reveal that the overall efficiency of the proposed traction unit can be improved compared to the other configurations. The advantages and drawbacks of the proposed traction unit are also investigated. Finally, experiments are conducted to validate the analysis. [ABSTRACT FROM AUTHOR]

This paper presents a flux-weakening model predictive control (FW-MPC) for the interior permanent magnet synchronous motor (IPMSM) drive system. The FW control is a strategy to extend the IPMSM's operating region. However, the primary FW needs to track the torque reference and maximize the electrical torque per current amplitude with the current and voltage limitations. The two objects make it impossible to solve the FW problem using the optimization method. We proposed an equivalent optimization problem to simplify the complex FW problem, including two objective functions. The MPC is selected as the controller due to its high robustness and transient performance. The constraints from the equivalent optimization problem are added in the MPC to control the IPMSM in the FW region. The simulation and experiment results indicate that the proposed FW-MPC is feasible and effective in driving the IPMSM in the FW region. The proposed FW-MPC can find the optimal point with the maximum electrical torque satisfying the current and voltage limitations. Therefore, the proposed FW-MPC can extend the IPMSM's operating region, benefiting the IPMSM's application. [ABSTRACT FROM AUTHOR]

This paper proposes the starting method for position sensorless controlled interior permanent magnet synchronous motors (IPMSMs) by using all-pass filters. The starting of IPMSM position sensorless control is well known to be extremely difficult due to the lack of electromotive information. Therefore, IPMSM is often started and accelerated with the high-frequency signal injection in general, and then, the control algorithm is switched to position sensorless control without high-frequency injection in middle speed region. However, the acoustic noise due to high-frequency signal injection would occur, and the switching of control methods would cause some bumps. For this reason, IPMSM is desirable to be driven from the start to the steady state without high-frequency signal injection. This paper realizes to start the position sensorless controlled IPMSM without high-frequency signal injection by allpass filter with the assistance of the appropriate initial vector setting of each controller, under the assumption that the high-frequency signal injection is used only at standstill. Finally, this paper experimentally demonstrates the feasibility and the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The square-wave voltage signal injection method with the proportional-integral (PI) observer is commonly adopted to estimate the rotor position of interior permanent magnet synchronous motor (IPMSM). However, the saliency estimation method with PI observer is a continuous injection method and the polarity identification method is a discrete one, which causes extra transition time and complexity. To solve this problem, a fast unipolar sequence-pulse injection method is proposed to unify the process of saliency and polarity identification and the complexity of the algorithm as well as the identification time are reduced. At the same time, a four-stage search algorithm is proposed to ensure the fast convergence and improve the accuracy by reducing the number of the pulse voltage signals. The experiment on motor drive platform verifies the effectiveness of the proposed method to IPMSMs with different saliency ratios. [ABSTRACT FROM AUTHOR]

Parameter mismatches in conventional model predictive current control (MPCC) would worsen torque and THD performance. To eliminate the parameter dependence of MPCC, this letter proposes a model-free predictive current control (MFPCC) for a three-level inverter-fed interior permanent magnet synchronous motor (IPMSM). Firstly, to increase the current difference updating frequency in the diode neutral-point-clamped (NPC) three-level inverter, a synchronous updating method is proposed in a manner where the number of updated current differences during one sampling period is increased up to 6. Secondly, for the sake of computational burden alleviation, a candidate vector selection algorithm is introduced in such a way that the number of candidate vectors is reduced to only 7–9. Then, the problem of neutral-point voltage fluctuation which is inherent to the three-level NPC inverter is investigated, and a reasonable replacement method incorporating the redundancy characteristic of small vectors is developed. Finally, experimental results verify that the system robustness against mismatched parameters can be greatly enhanced by use of the proposed control scheme; meanwhile, steady-state performance and dynamic-state response of the system can be improved to some extent as well. [ABSTRACT FROM AUTHOR]

In this paper, a traction motor for maximum power 76kW electrical vehicle (EV) was designed, and the design results were verified through experiments. One of the important design objectives of the traction motor for EV is to improve energy efficiency. The energy efficiency of a traction motor affects the mileage of electric vehicles (EVs). Among the design factors influencing energy efficiency, shape parameters include torque per rotor volume (TRV), torque density (TD) and shape ratio (SR). These shape parameters have an impact on the motor's phase back EMF, inductance, winding resistance and core loss resistance, eventually affecting the energy efficiency in the entire operating range of the motor. In this paper, a New European Driving Cycle (NEDC) was applied to calculate the energy efficiency of the traction motor for EV. Changes in motor parameters such as phase back electromotive force (EMF), inductance, winding resistance and core loss resistance were identified according to variations in shape parameters. In addition, the motor characteristics according to the changes of these parameters were confirmed, and shape parameters to improve energy efficiency were selected. Since the traction motor designed in this paper adopted a water cooling method, thermal analysis was performed by reflecting the water cooling method in the thermal equivalent circuit (TEC). In order to confirm the reliability of the analysis method and design, a load test was conducted on the entire operating range to calculate energy efficiency, and a temperature test was performed to compare the test results with the analysis results. [ABSTRACT FROM AUTHOR]

This article presents a finite-element-based, multiobjective design optimization study of the fractional-slot, concentrated wound, permanent magnet synchronous machine (FSCW PMSM). Design objectives included maximization of efficiency, minimization of cost and low ripple without sacrificing torque density and wide constant power speed range. A large-scale optimization study revealed that while a V-type rotor provides high torque density, a spoke-type rotor has the benefit of low torque ripple. Quest for a design that can combine the goodness of both V- and spoke type rotors for an FSCW stator has led to a novel interior permanent magnet rotor topology referred here as Y-type. The goals of achieving maximum efficiency, minimum cost and wide CPSR were also accomplished in the proposed Y-type FSCW IPMSM. For experimental verification purpose, three fully optimized rotors - V-, spoke- and Y-type were constructed for a 12-slot/10-pole FSCW stator. Extensive experimental tests were conducted on three machines for a detailed comparison study. It will be shown that the proposed Y-type FSCW IPMSM outperforms both V and spoke-type configurations. A scaled-up version of the Y-type FSCW IPMSM shown to have satisfied many of the Freeedomcar 2020 targets, which is promising for application in electric vehicles. [ABSTRACT FROM AUTHOR]

This paper proposes a model-free predictive current control (MFPCC) for interior permanent magnet synchronous motors (IPMSMs) with a multiple current difference updating (MCDU) technique. Firstly, to improve robustness against machine parameter variations and reduce the computational burden, current difference-based prediction that only requires accumulation operation is implemented, which avoids the model-based complex calculations in traditional model predictive current control (MPCC). Secondly, a MCDU technique is conducted with the characteristic of updating the current differences associated with voltage vectors in opposite directions. Thus, the updating frequency of the current difference can be significantly increased. Finally, the effectiveness of the proposed method is verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

In order to analyze and design the Interior Permanent Magnet Synchronous Motor (IPMSM), the parameters must be defined according to characteristics of the motor. To obtain a good motor, the decrease of leakage flux is done by reduction of mechanical stresses and increase of the magnetic flux density. The magnetic flux distribution in the air gap is first analyzed. Then, the rotor is designed by using a specific mathematical model. Two topologies based on placing of permanent magnet into the rotor, which is placing in parallel shape and V-shape, are analyzed and designed. The mechanical stresses and rotor strains occurring during the rotation at high speed are studied. [ABSTRACT FROM AUTHOR]

This study proposes a novel robust predictive current control that is based on a discrete‐time disturbance observer for an interior permanent magnet synchronous motor (IPMSM), does not require rotor flux information. To confirm the effects of the current control response on a parameter mismatch, the parameter sensitivity for the current prediction of a conventional deadbeat predictive current control (DPCC) is analysed. With the proposed method, disturbances owing to a parameter mismatch, rotor flux term, and unmodelled dynamics are estimated using a Luenberger observer in the discrete‐time domain. The estimated disturbances are compensated with the predicted reference voltage model considering a digital delay. The stability of the proposed disturbance observer owing to a parameter mismatch of the stator resistance and d–q inductance is also analysed. The proposed method is robust against the stator resistance and an inductance variation, and an accurate predicted current control can be obtained without an offline or online estimation of the rotor flux. Compared with the conventional DPCC, the proposed method can eliminate a steady‐state current and transient state error caused by disturbances of the system. Experimental results are presented to verify the proposed control scheme even with mismatched parameters of the IPMSM. [ABSTRACT FROM AUTHOR]

Studying the dynamic performance is very important for improving the performance of the electrical machines. The sudden applied or removal the load is very critical for the electrical machines. It may lead to some problems in it's as, mechanical stress, surge current, increase the losses and decrease the motor life time. So, this paper studied this problem and constructed proposal model to reduce the effect of this problem on the electrical machines. This occurred through comparing between the effect of the dynamic load, sudden applied and removal loads on the performance characteristics of interior permanent synchronous motor (IPMSM) with proposal model and with classical model in the constant flux region and in the field weakening region. The simulation is done through the MATLAB program. The simulation shows the effectiveness of the proposal model on the performance characteristics of the IPMSM. With proposal model, the overshooting and under shooting of the motor speed are reduced. Rise time and settling time are improved, the response of the motor torque for load variations is improved and the stator currents are decreased. In this model, the space vector pulse width modulation is used to controlling the inverter which used to drive the IPMSM. [ABSTRACT FROM AUTHOR]

Hybrid rotor position estimation methods that integrate a fundamental model and high frequency (HF) signal injection are widely used for the wide speed-range sensorless control of interior permanent-magnet synchronous machines (IPMSMs). However, the direct transition of two different schemes may lead to system fluctuations or system instability since two estimated rotor positions based on two different schemes are always unequal due to the effects of parameter variations, system delays and inverter nonlinearities. In order to avoid these problems, a seamless transition strategy to define and construct a virtual q-axis inductance is proposed in this paper. With the proposed seamless transition strategy, an estimated rotor position based on a fundamental model is forced to track that based on HF signal injection before the transition by adjusting the constructed virtual q-axis inductance. Meanwhile, considering that the virtual q-axis inductance changes with rotor position estimation errors, a new observer with a two-phase phase-locked loop (TP-PLL) is developed to accurately obtain the virtual q-axis inductance online. Furthermore, IPMSM sensorless control with maximum torque per ampere (MTPA) operations can be tracked automatically by selecting the proper virtual q-axis inductance. Finally, experimental results obtained from an IPMSM demonstrate the feasibility of the proposed seamless transition strategy. [ABSTRACT FROM AUTHOR]

This paper describes a flux intensifying permanent‐magnet (PM) motor with variable leakage magnetic flux. The unique feature of this proposed motor is the ability to passively adjust the magnetic flux linkage into the armature windings in proportion to the armature magnetomotive force and/or armature current phase. The magnetic circuit topology of the flux intensifying PM motor and the passive variable leakage magnetic flux are determined through FE analysis. Then, the driving performance is experimentally elucidated through comparison with that of a reverse salient pole type (flux weakening) PM motor without variable leakage magnetic flux. [ABSTRACT FROM AUTHOR]

In this paper, an outer rotor interior permanent magnet synchronous machine (IPMSM) with hybrid permanent magnet (PM) material is proposed. The key is to adopt the outer rotor structure with two-layer crescent barriers and hybrid PM material to maximize the output torque and reduce the usage of high-cost rare-earth PM. The ferrite PMs are filled in the middle of the crescent barriers with thicker thickness, while the rare-earth PMs are filled into the bilateral of the crescent barriers with thinner thickness. To verify the effectiveness of the proposed rotor structure, optimizations are first carried out among the conventional rotor structures with single kind of PM material and the proposed rotor structure with hybrid PMs. Then, detailed comparisons have been investigated. Results indicate that the proposed machine has higher torque density than the machine with only ferrite PM and can reduce almost half the usage of rare-earth PM in comparison to the machine with only rare-earth PM. Moreover, the proposed rotor structure is further optimized considering productivity. [ABSTRACT FROM AUTHOR]

Permanent magnet (PM) motors adopt interior V-type PMs and fractional-slot concentrated winding for improving the torque density and efficiency. However, the no-load magnetic coefficient will be increased, which would reduce the utilization rate of the PM. The structure parameters of the rotor should be designed reasonably, especially the bridge. This paper calculates the no-load leakage coefficient by establishing the analytical model of the no-load magnetic coefficient. It shows that, the bridge size has an important effect on the no-load magnetic coefficient. The analysis results are verified by the two-dimensional finite element analysis and tests. [ABSTRACT FROM AUTHOR]

To increase output torque in the constant power region of interior permanent magnet synchronous motor (IPMSM) for electric vehicle/hybrid electric vehicle applications, a novel torque control based on voltage phase angle control is proposed to provide more accurate torque for the IPMSM. First, the mathematic model of the IPMSM under six‐step voltage operation is derived. Then, the phasor diagram based on the fundamental frequency and ideal condition is used to explain the relation between the torque, power, and voltage phase angle. Moreover, Maxwell 2D simulation for the IPMSM shows the detailed phenomena including generated torque, phase current, and magnetic flux distribution for developing controllers. Hence, the proposed method uses phase voltage advancing angle to yield torque, which consists of a command feed‐forward controller to give a fast dynamic response, a proportional–integral regulator, a high‐resolution voltage angle injection to reduce torque ripple and an efficiency‐based torque estimator to enhance torque accuracy under six‐step voltage operation. Finally, a digital signal processor(DSP)‐based motor drive is built to verify the proposed method using a 6kW/47Nm/1200rpm IPMSM. The experimental results measured by a torque transducer are derived to show that the torque ripple is significantly reduced, torque accuracy is improved, and constant power control achieved is from 1800 to 3600rpm. These results, therefore, confirm the superior performance of the proposed control method. [ABSTRACT FROM AUTHOR]

Position‐sensorless positioning control system of interior permanent magnet synchronous motors (IPMSMs) has been energetically researched for high reliability and cost reduction. To achieve fast response of positioning servo systems, accurate parameters of IPMSMs are required. The parameters vary due to temperature and/or ageing, which results in degradation of the positioning control performance. Thus, this study proposes a position‐sensorless adaptive positioning control system for IPMSMs using the dynamic certainty equivalence principle for stable parameter identification. In addition, comb filters are used for fast estimation instead of low‐pass filters. Experiments are demonstrated to validate the effectiveness and the feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes a torque control method for interior permanent magnet synchronous motors (IPMSMs). The proposed method uses state feedback control based on a new n‐t coordinate system and controls the voltage amplitude and phase based on the coordinate system. The t‐axis is a tangent line of the constant voltage ellipse, and the n‐axis is a normal line of the ellipse. The n‐axis current is utilized to place the poles of the transfer function at the desired position and reduce the mutual coupling between the voltage amplitude controller and phase controller. The proposed method realizes a high torque response even under parameter variation for the linear range and over‐modulation range of the inverter, including a 6‐step mode. The effectiveness of the proposed method was verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

Interior permanent magnet synchronous machines (IPMSMs) are gaining popularity in e-mobility applications due to their wide constant power speed range when compared with other electric motors. The high-performance of IPMSMs is due to the pronounced degree of magnetic saliency, which originates from embedding their magnets inside the rotor. Yet, this feature complicates their control since it increases nonlinear phenomena such as cross-magnetization and saturation. This results in pronounced variations of the machine inductances, which are highly dependent on the machine current. This behaviour is of particular relevance in e-mobility applications, where a highly dynamic operation of the machine is required. In contrast to most existing current control approaches, where precise inductance knowledge is required, we address this challenge by deriving a controller that exploits the machine dynamics to achieve exponential current tracking in the presence of unknown and varying inductances. By interpreting the flux linkage as a modelled disturbance, we propose a dynamic compensator based on the internal model principle. As a by-product, the method provides an estimate of the flux linkage. The gain in performance compared to the standard PI controller is illustrated in simulation. [ABSTRACT FROM AUTHOR]

In the near future, usage of heavy rare-earth element needs to be reduced, due to resource risk and rising price with vehicle electrification. This paper compared two hybrid electric vehicle traction motors of the same size using Nd sintered magnet and heavy rare-earth free magnet. We designed two interior permanent magnet synchronous motors varying only the rotor design and material. A new motor was developed using heavy rare-earth free magnet with performance and size equal to Nd sintered motor. The rotor shape was designed as the one of a synchronous reluctance motor to overcome the lack of heavy rare-earth free motor torque. The motor performance was verified with a series of experiments. [ABSTRACT FROM AUTHOR]

Direct torque and flux control (DTFC) is known for its reduced torque and flux ripples compared to the classical direct torque control scheme. It can drive an interior permanent magnet synchronous motor (IPMSM) in usual control regimes while satisfying current and voltage limits of the system. However, deep flux‐weakening control of an IPMSM under DTFC has not been investigated as extensively, especially operation along the maximum torque per voltage (MTPV) trajectory in the torque‐flux plane. This study proposes a simple and effective control method, which incorporates MTPV trajectory in the conventional flux‐weakening algorithm of DTFC. Performance of an IPMSM drive is analysed when operated with the proposed control method. [ABSTRACT FROM AUTHOR]

Taking a 2.2 kW 380 V IPMSM (Interior Permanent Magnet Synchronous Motor) as the research object,the two-dimensional finite element model is established by using finite element analysis software and the external circuit is built using the Maxwell circuit.The short circuit faults of the motor during the running process are realized using the voltage control switch.Extracting the minimum magnetic flux density of the permanent magnet in the process of short circuit faults to generate the magnetic cloud image with the help of macro file,it is the basis for judging the demagnetization of permanent magnets.If the minimum flux density under different short circuit faults is lower than the knee-point magnetic density of the demagnetization curve at the corresponding temperature,the permanent magnet in the region is demagnetized.The analysis results provide a theoretical basis for analyzing the demagnetization fault of permanent magnet motor. [ABSTRACT FROM AUTHOR]

The present work deals with the calculation of the time varying induced emf in permanent magnet synchronous machines from the numerical finite element solution. A review of the existing methods is presented; their intrinsic merits, in terms of accuracy and speed of computation, are compared. The currently used method, which relies on a weighting averaging procedure of the magnetic vector potential (MVP) over the slot area in order to derive the winding flux linkage and the stator induced, has been modified to enhance its accuracy. An alternative method, which relies on the magnetic vector potential distribution along the mid airgap line, is proposed to carry out the same task. This approach has turned out to be very efficient since it enables a straightforward data handling, signal reconstruction, filtering and spectrum analysis of the relevant waveforms to be easily implemented in a single post-processing function. Finally, the relevance and efficiency of each method, in terms of accuracy and speed of computation, has been confirmed by the experimental results. [ABSTRACT FROM AUTHOR]

In this paper, a high-performance torque control scheme of an interior permanent magnet synchronous machine (IPMSM) is introduced, which focuses on both steady state and transient torque dynamics of the IPMSM under the maximum torque per ampere (MTPA) condition. For the proposed control scheme with model-based torque correction, an accurate and efficient torque control with robust torque response can be achieved for the MPTA operation. Global stability and performance of the proposed torque control scheme are theoretically guaranteed. The current limitation of the IPMSM is easily handled without anti-windup and without degrading the torque dynamics or stability even the torque demand is beyond the maximum reachable torque. Implementation issues of the proposed control scheme to the real IPMSM plant with parameter variation are discussed. With the compensation of the linear and nonlinear inverter voltage drop, a robust and accurate torque response for the real-time MTPA operation can be achieved by an adaptive current control and online parameter estimation. The simulation and experimental results validate the safety and high performance of the proposed torque control scheme. [ABSTRACT FROM PUBLISHER]

SUMMARY This paper presents a new position sensorless control system for an interior permanent magnet synchronous motor (IPMSM). The proposed method is based on the extended electromotive force (EMF) and voltage injection synchronized with a pulse-width modulation carrier. The proposed method does not need to switch the estimation method by speed in order to estimate the magnetic pole position by extended EMF, even at low speeds. Further, the amplitude of the superimposing voltage is changed according to the extended EMF; the applied voltage is not saturated in the high-load and high-speed regions. The effectiveness of the proposed sensorless control system was verified experimentally. [ABSTRACT FROM AUTHOR]

SUMMARY This paper presents a multiobjective optimization using genetic programming (GP). In this method, an analysis model is regarded as a tree structure. This tree structure is divided into polygons and material information. Therefore, this method can be applied GP. Additionally, authors take into consideration about shape complexity. The target of electromagnetic device is an interior permanent magnetic synchronous motor (IPMSM). This method optimizes flux barriers in IPMSM by two-dimensional finite element method. The purpose of this paper is an investigation of design optimization by multiobjective optimization. Authors reveal the Pareto optimal solutions of characteristics for average torque and torque ripple of IPMSM. [ABSTRACT FROM AUTHOR]

In this study, an easily implementable and effective method in loss‐minimisation control of interior permanent‐magnet synchronous motors (IPMSMs) is proposed. Complication of loss‐minimisation condition and its implementation are main problems in model‐based control methods of IPMSMs. To resolve these problems, an approximate‐model is used for simplification of loss‐minimisation condition and a proportional–integral‐controller is utilised to directly solve the loss‐minimisation condition. Also, saturation and iron loss resistance variation due to frequency variation are considered in the proposed method. Furthermore, results show the high precision of the proposed method in comparison with accurate model. Steady‐state performance of the proposed method is compared with look‐up table‐based loss‐minimisation and maximum torque per ampere (MTPA) control methods. Also, experimental results verify performance, good dynamic response and effectiveness in loss reduction of the proposed method under different conditions in comparison with look‐up table‐based loss‐minimisation and MTPA control methods. [ABSTRACT FROM AUTHOR]

SUMMARY This paper proposes a torque control method for interior permanent magnetic synchronous motors (IPMSMs). The proposed method controls the voltage amplitude and phase based on a new n- t coordinate system. The t-axis is a tangent line of a constant voltage ellipse, and the n-axis is a normal line of the ellipse. On the n- t coordinate system, the n-axis current is not affected by the voltage phase. The n-axis current is utilized to reduce the mutual coupling between the voltage amplitude controller and phase controller. The proposed method realizes a high torque response for the linear range and overmodulation range of the inverter, including six-step mode. The effectiveness of the proposed method was verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper introduces a novel flux observer for direct torque controlled interior permanent magnet brushless AC (IPM-BLAC) drives over a wide speed range including standstill. The observer takes machine nonlinearities into account and is independent of inverter nonlinearities, dead time, and armature resistance variation at steady states since such inaccuracies are compensated quickly by measured phase currents. Magnetic saturations in the stator and rotor cores, cross-coupling effects of flux linkages of the motor, and spatial harmonics in the magnetomotive force are all considered in the novel scheme. There is no filter; hence, no delays and oscillatory responses like in conventional schemes where filters are employed to prevent integrator drift issue. Superiority of the observer when compared to the state-of-the-art schemes has been illustrated by both extensive simulations and experimental results of a 10-kW IPM-BLAC machine designed for traction applications. [ABSTRACT FROM AUTHOR]

SUMMARY Interior permanent magnet synchronous motors (IPMSMs) position sensorless drives have been widely used in recent years. These drives should be able to handle low-speed operation. Control methods of IPMSM based on current observers generally assume that the position error is sufficiently small. In this paper, the authors have proposed a new position estimation method based on vector trajectory of the current estimation error. This position estimation method consists of two parts. First, the sign of the position error is estimated based on the outer product of the current estimation error and the reference vector. Next, the amplitude of the position error is calculated from the intersection of two circles determined by motor parameters and the current estimation error. The proposed position sensorless method is implemented on a DSP controller, and the effectiveness of the proposed control method is confirmed experimentally. [ABSTRACT FROM AUTHOR]

In this study, the interturn fault (ITF) models of interior permanent magnet synchronous motors (IPMSMs) employing series and parallel winding connections were developed through the addition of saliency modeling to the surface-mounted permanent magnet motor models presented in a previous work. The saliency model was obtained by using deformed flux models based on both the fault winding flux information and inductance variations caused by cross-flux linkages that depend on the distribution of same-phase windings. By assuming a balanced three-phase current injection, positive and negative sequence voltages, and the fault current are obtained in the positive and negative synchronous reference frames. The output torque models were developed by adding the magnet and reluctance torques, which were derived from the developed models. To verify the proposed IPMSM models with an ITF, a finite element method-based simulation and experimental measurements were performed; the results are presented in this paper. [ABSTRACT FROM AUTHOR]

In many applications, interior permanent magnet synchronous machines (IPMSMs) with fractional slot concentrated windings (FSCWs) are considered promising candidates in terms of higher power density and efficiency. In addition, employing a multiphase stator winding improves the drive train availability and increases reliability. This study investigates the effect of applying stator shifting to five‐phase FSCW winding IPMSMs to suppress the effect of the slot harmonics by doubling the number of slots. In this case, the winding coil pitch will be two, which stands as a compromise between single‐tooth and distributed winding topologies. This highly improves the air gap flux distribution, significantly reduces both rotor core and magnet eddy current losses, and increases saliency ratio and reluctance torque component. Moreover, an improved performance under fault conditions, in terms of lower torque ripple, and core and magnet losses, adds to the main advantages of this technique. Various slot/pole combinations suitable for five‐phase machines are investigated. A full simulation case study based on two‐dimensional finite element analysis is applied to the 20‐slot/18‐pole stator with single‐tooth winding under both healthy and open‐circuit phase fault cases. [ABSTRACT FROM AUTHOR]

The effects of different winding connections, i.e. series, parallel, and series–parallel combined windings is studied, on the unbalanced magnetic pull (UMP) in an interior permanent magnet synchronous machine (IPMSM) with eccentricity applied. Three types of eccentricities, i.e. static, dynamic, and mixed eccentricities, are investigated. Four types of winding connections are examined and the contributing factors, such as air gap difference, current redistribution, and slot effect on the UMP are analysed. FFT analysis and UMP distribution patterns are used to compare the four types of winding connections. The results show that the current redistribution generated by the parallel connections of the windings results in reduction of UMP for IPMSM with eccentricity. [ABSTRACT FROM AUTHOR]

This paper presents the development of an electric-vehicle (EV) interior permanent-magnet synchronous motor (IPMSM) drive and its operation control. The power circuit of the established EV IPMSM drive consists of a two-leg interleaved bidirectional front-end dc/dc buck–boost converter and a three-phase inverter. The front-end converter can establish adjustable and boostable dc-link voltage for the motor drive to enhance its high-speed driving performance. It can also allow the battery bank to be charged from the motor during regenerative braking. Good current sharing control between converter modules and dc-link boosted voltage regulation response are preserved via the developed robust control scheme. Moreover, fast disturbance rejection response against the module fault and recovery is achieved. The comparative driving performance enhancements via dc-link voltage boosting and commutation instant tuning are conducted. Then, through proper setting and control, the established EV IPMSM drive possesses good driving performances, including starting, acceleration/deceleration, regenerative braking, and reversible operation characteristics. [ABSTRACT FROM AUTHOR]

This paper presents the establishment and operation control of a dc microgrid incorporating with electric vehicle (EV) as movable energy storage. The developed microgrid consists of a wind permanent-magnet synchronous generator ac source and a dc source, a battery/supercapacitor (SC)/flywheel hybrid energy storage system, and a grid-connected bidirectional single-phase three-wire (1P3W) load inverter. Various harvested ac and dc sources can be plugged into the microgrid via the developed interfaced power converters. In addition to good microgrid operation performance, the microgrid-to-grid and grid-to-microgrid operations can be successfully conducted with good power quality. As to the developed EV interior permanent-magnet synchronous motor drive, the SC auxiliary storage is equipped to assist the main battery source in intermittent energy conversion. Satisfactory acceleration/deceleration/reversible and regenerative braking operation characteristics are obtained via the developed power stages and control schemes. Moreover, the successful microgrid-to-vehicle and vehicle-to-microgrid interconnected operations of EV and microgrid are achieved. In addition, the vehicle-to-grid/grid-to-vehicle operations can be also performed via the developed 1P3W inverter. [ABSTRACT FROM AUTHOR]

This paper presents an analytical approach for evaluating the magnet eddy-current losses of interior permanent-magnet synchronous machines (IPMSMs) during flux weakening. To investigate the magnet eddy-current losses, an analytical method of the time-varying magnetic flux density in the magnet is proposed based on the armature reaction magnetic field analysis. According to the time-varying magnetic flux density, a coefficient is used to evaluate the magnet eddy-current losses during flux weakening. The coefficient can indicate how the major design parameters in an IPMSM affect magnet eddy-current losses during flux-weakening operation. Finite-element analysis was used to validate the proposed model and calculate the magnet eddy-current losses of IPMSM with different design parameters. [ABSTRACT FROM AUTHOR]

Due to slotting effects and non-sinusoidal flux distribution, permanent magnet synchronous motors have relatively large torque ripples. Furthermore, core saturation, along with armature reaction, intensifies the cross coupling between d-axis and q-axis dynamics, and causes changes in the rotor flux linkage. In this paper, it is attempted to develop a closed-form analytical torque equation and inductances, which are known to be uneasy due to the above non-linearities. This approach is based on the flux linkages obtained via finite-element analysis for all current sets in an operation area. First, a flux linkage is obtained for each phase coil as the rotor rotates over one electrical period. At this time, synchronous ac currents are injected to the stator coils. Then, the resulting flux linkages appear as sinusoidal curves with harmonics. They are transformed into a synchronous dq-frame and expanded by Fourier series. Then, the Fourier coefficients, reflecting high-order flux components caused by the permeance change associated with the rotor motion, are dependent on the magnitudes of current. Second, the Fourier coefficients of the same harmonic number are collected over many current samples and interpolated by polynomial functions in dq-axis current. In the interpolation process, the coefficients are obtained through a least square method. Then, an estimate of flux linkage is reconstructed analytically using the resulting interpolations. Analytic expressions for inductances and torque are obtained by dividing or by differentiating the flux linkage estimates. The accuracy is evaluated by comparing the results from finite element method (FEM) and the experimental results. [ABSTRACT FROM AUTHOR]

This study investigates the influence of the stator configuration of low‐speed sensorless‐controlled interior permanent magnet synchronous motors (IPMSMs) with concentrated winding on the sensorless drive feasibility and iron loss. To evaluate the sensorless controllability of the motors, a mathematical and simulation process of estimating the rotor position error is proposed. In addition, the harmonic iron loss under a load condition is analysed via two‐dimensional non‐linear finite element analysis. Considering both the sensorless drive feasibility and iron loss, the four different IPMSMs, which have different tooth tip configurations in the stator, are examined. It is shown that the machine with a relatively short and thin stator tooth tip has better sensorless drive controllability and lower harmonic iron loss than the others. Based on the analysis result, a final model applied with stator chamfer for electric vehicle traction is proposed and manufactured. The validity of the simulations and the design method are verified by the experiments. [ABSTRACT FROM AUTHOR]

This paper presents a robust high-order sliding mode interconnected observer and an integral backstepping controller for a sensorless interior permanent magnet synchronous motor. To limit the chattering phenomenon on the observed state, a super twisting algorithm is combined with an interconnected observer to design a new high-order sliding mode observer which will be used for multiple-input multiple-output systems. The proposed observer is used to estimate in finite time the rotor position, the speed and the stator resistance. Moreover, a robust nonlinear controller based on the backstepping algorithm is designed where integral actions are introduced step by step. This controller allows to track a desired reference which is computed by using a maximum-torque-per-ampere strategy. Simulation results are shown to illustrate the performance of the proposed scheme by using significant trajectories including the zero speed and under parametric uncertainties. [ABSTRACT FROM AUTHOR]