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Home appliances such as residential air conditioners are based on the variable speed drives for AC motors such as IPMSM and IM. These variable speed drives always require the simple and low‐cost system configurations without the large electrolytic capacitors, reactors, and power devices that consist of PFC converters. This paper surveys and analyzes the proposed and advanced control techniques to achieve high input power factor and sinusoidal source current control in electrolytic capacitor‐less inverters. The investigated control methods consist of control algorithms based on the energy flow between input and output of the electrolytic capacitor‐less inverter, and all of them are useful as high‐power factor control methods for compressor drive motors such as air conditioners. Moreover, these techniques realize the variable speed drives for AC motors to meet power supply harmonics regulations (IEC61000‐3‐2). © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The authors present the multi‐physical field performances comparative research for a 30 kW, 30,000 r/min high‐speed permanent magnet motor (HSPMM) when the motor is powered by the sinusoidal pulse width modulation (SPWM) voltage inverter and sinusoidal voltage source, respectively. Firstly, electromagnetic performances including torque, voltage and current of the HSPMM with different driving methods are compared and analysed by the finite element method (FEM). Considering the effects of high operation frequency, power losses of the HSPMM with different driving methods under full‐load conditions are calculated and compared with the skin effect and the proximity effect considered for HSPMM winding copper loss estimation. Based on the above analysis, a prototype driven by the SPWM voltage inverter is manufactured, with its electromagnetic and thermal performances tested and verified. In addition, several influencing factors of the HSPMM rotor eddy current loss are studied, with their effects on the HSPMM under different driving methods further analysed and compared as well. A novel equivalent power supply method is proposed to effectively save the calculation time with a negligible error. Finally, in order to further improve the heat dissipation capacity of the HSPMM, a novel cooling method is intensively studied with its influencing factors further analysed. The cooling effect of the novel cooling method and the temperature of the motor components are verified and calculated by the computational fluid dynamics (CFD) method. [ABSTRACT FROM AUTHOR]

Machine acoustics is an important area of research impacting the quality and comfort of human life. With increased levels of electrification and the wider use of electric motors, the contribution of motor drives towards quieter acoustic systems becomes increasingly important. This paper presents a novel acoustic improvement method involving the use of acoustic waves generated from High Frequency Injection to perform Active Noise Control. Although High Frequency Injection has been used widely in the domain of sensorless motor control, its acoustic generation process has been so far perceived as a negative by‐product. This paper presents the analysis and experimental results from the application of the proposed method to the Helicopter Electro‐Mechanical Actuation System. Considering the extensive use of motor drives in a number of industries, the proposed practice of High Frequency Injection Active Noise Control can have a significant impact to future applications. [ABSTRACT FROM AUTHOR]

In order to address the issues of complexity, high cost, large volume, and low reliability associated with traditional H‐bridge cascaded converters when operating under high voltage, high capacity, and dual electric motor loads, the authors propose the utilisation of a nine‐switch converter as an alternative to the conventional H‐bridge converter for implementing cascaded multilevel converters in dual electric motor drive systems. After conducting an analysis and research on the topology and operational control strategy of cascaded multilevel converters based on the nine‐switch converter, a design is presented using six individual nine‐switch converter units to develop a cascaded multilevel converter capable of driving two 3 MW asynchronous electric motors at a 6 kV voltage level. Simulation verification is performed, and a scaled‐down prototype is built for experimental validation. The results demonstrate that, in comparison to traditional H‐bridge cascaded converters, the proposed cascaded multilevel converter can effectively drive dual electric motors at the same or different frequencies while reducing the number of switches to 1/4, the total transformer windings to 1/2, and Direct Current‐side capacitors to 1/6. This improvement enhances system reliability, portability, and load adaptability, thus offering increased versatility in dual electric motor drive applications. [ABSTRACT FROM AUTHOR]

The paper carries out the research on a novel two‐level voltage source inverter to further improve the output power quality of the inverter under the premise of efficient operation. Main switches can realize zero‐voltage switching in a wide load range to ensure the efficient operation of the designed inverter. Total harmonic distortion (THD) of the output current at low output frequencies can be improved by the modification of resonant tanks in the designed inverter. In the dead time, the modified resonant tanks can result in a shorter duration of nonlinear changes in the output phase voltage at lower load current, which is beneficial for reducing the output voltage error caused by dead time. The improved power quality at low output frequencies is conductive to the use of the designed inverter in the drive system of the low‐speed AC motor. The paper expounds every operating status during a switching period. The experiment manifests that switches realize soft switching. The efficiency of the designed inverter reaches 98.6% at rated operation state, which is 0.3% and 0.5% more than that of two comparison objects, respectively. Moreover, when the output frequency reduces to 5 Hz, the THD of the output current is only 2%, which is also less than that of comparison objects. Hence, the designed inverter has advantages in the efficiency and the output power quality. [ABSTRACT FROM AUTHOR]

Precise electromagnetic transient simulation of induction motors (IMs) under voltage sag condition is necessary in Electro‐Magnetic Transient Programme. Although traditional fifth‐order model can accurately reflect the electromagnetic transient behaviour of IMs, the disadvantage of massive computation limits its application in the large‐scale system simulation. Considering voltage sag is a typical power quality issue, a novel reduced‐order electromagnetic transient model based on equivalent flux linkage derivative is proposed to shorten simulation time during voltage sag. When characteristic parameters of voltage sag are given, an equivalent flux linkage derivative can be obtained simply, and the proposed model can effectively shorten the simulation time while ensuring accuracy of the fifth‐order model. Simulation results of small capacity (5.5‐kW) and large capacity (315‐kW and 1600‐kW) IMs in simple system and IEEE 9‐bus system confirm the applicability of the proposed model. It is estimated that simulation time of the proposed model decreases by 76% compared with the fifth‐order model. Finally, the experimental validation with the 5.5‐kW IM is carried out to show the effectiveness of the theory. [ABSTRACT FROM AUTHOR]

Summary: In a unidirectional five‐level ac motor drive system with open‐end winding connection, because of the variation of operating frequency of ac motor, the instantaneous power fluctuation of rectifier stage and inverter stage will generate larger voltage ripple on each phase dc‐link capacitors, and further lead to a large amount of current harmonics in output currents of inverter. To cope with this problem, an improved space vector pulse width modulation (SVPWM) strategy based on dc‐link voltage feedforward is proposed. In this paper, the effects of zero sequence current harmonics caused by dc‐link voltage ripple on ac motor are firstly analyzed, including the stator winding flux linkage equation, voltage equation, and electromagnetic torque. Then, the generating mechanism of dc‐link voltage ripple and the current harmonics are discussed in detail in terms of instantaneous power fluctuation of each single‐phase converter. Based on this, an improved SVPWM strategy by modifying the modulation signal is proposed to suppress the generation of current harmonics. Finally, a 2.2 kW prototype experimental results are given, which verify the feasibility and advancement of the proposed modulation strategy. [ABSTRACT FROM AUTHOR]

In ultra‐high speed (UHS) motor applications, full SIC two‐level (2L) inverters with high switching frequencies are generally used due to their lower cost. However, even with the usage of all WBG power devices, high‐frequency hard‐switched 2L inverters still do not achieve optimal efficiency characteristics. As a result, in order to simultaneously reduce the switching frequency and enhance overall efficiency, recently three‐level (3L) topologies have emerged as a promising solution. Nevertheless, to fully meet the requirements of UHS applications, the switching frequency of 3L inverters should be increased beyond 30 kHz, which necessitates the usage of all SIC power devices. This, in turn, leads to a potential drawback where the cost of the drive system may become prohibitively high due to the requirement of all SIC switches. To address this issue and reduce the cost of a full SIC 3L inverter, a new 3L simplified sparse NPC (SSNPC) topology is proposed in this work. The operational principle of this topology, its distinctive control features, and the advantages it offers specifically for UHS applications are presented. Additionally, to further increase the efficiency and reduce the influence of dead time at low speeds, a new switching sequence is introduced. Finally, the overall performance and efficiency characteristics of the high‐frequency SSNPC inverter were verified across all operational conditions of UHS motor drive system. [ABSTRACT FROM AUTHOR]

Safety and reliability are very important in machine driving systems for many industries. A novel rotor flux‐based Vector Control (VC) strategy for Y‐connected 3φ Induction Machines (IMs) without speed sensor under the Single‐Phase Fault (SPF) is proposed. The sensorless VC technique is based on using Asymmetrical Transformation Matrices (ATMs) for stator voltage and current components as well as an Extended Kalman Filter (EKF) for estimation of the speed and d‐q fluxes. Furthermore, a simple model‐based SPF detection mechanism based on the EKF is suggested. The performance of the proposed control scheme for a 1 HP sensorless Y‐connected 3φ IM prototype is validated by several experiments. According to the experimental results, the designed scheme during the SPF has several advantages of improved phase currents and low speed, flux, and torque ripples. [ABSTRACT FROM AUTHOR]

A stacked polyphase bridge converter consists of multiple standard, three‐phase two‐level voltage source inverters connected in series to the same dc voltage source. The authors present a decentralised and dynamic dc‐bus reconfiguration strategy for this type of converter. The innovation of the proposed strategy lies in its ability to isolate or reactivate one of the inverters in the series connection online, even in motoring mode, enabling increased fault tolerance and an extended speed range. Both the required hardware alterations and the multi‐agent control strategy are addressed. Its major benefits compared to the state‐of‐the‐art are that only two additional active, unidirectional semiconductor switches are required per inverter, and that the control is based on local computations, local measurements and neighbour‐to‐neighbour communication only. Hence, the scalability and reliability of the hardware are extended towards the control. Simulations and experimental results on a 4 kW modular axial‐flux PMSM prove the feasibility of the concept, and validate that the dc‐bus can be reconfigured in 100 ms, without torque interruption. [ABSTRACT FROM AUTHOR]

A simple control structure with high anti‐disturbance ability is proposed here for permanent magnet synchronous motor (PMSM) drives. The conventional cascade structure, with an outer speed loop and an inner current loop, is simplified and merged into one single‐loop controller. To enhance the dynamic performance and efficiency of the PMSM drives, an enhanced adaptive reaching law (EARL) is proposed for the single‐loop control strategy. In comparison with conventional reaching laws, the EARL can increase the convergence speed, adapt the gain to fit the system state, and reject the chattering phenomena of conventional sliding mode control. Moreover, an improved disturbance observer (DOBS) is developed to work with the main controller. The DOBS aims to enhance the estimation accuracy of real‐time unknown disturbances in the PMSM system, thereby further improving the disturbance rejection capability through feedforward compensation for the single‐loop control strategy. The EARL and DOBS thus enhance the robustness of the control strategy and ensure high dynamic performance at various motor operating conditions. The performance and efficiency of the proposed control are validated through simulations and experimental studies. [ABSTRACT FROM AUTHOR]

In order to ensure the high precision and good dynamic characteristics of the dual‐axis linear motor when machining components, the tracking error and contour error should be reduced with more complex machining trajectory. In this study, the characteristic model of position control of the linear motor is established by using the modelling principle of the characteristic model, and the intelligent adaptive controller is designed. In addition, a new calculation method of the equivalent contour error is proposed innovatively, and the dual axis is compensated by proportional feedback control, to improve the contour accuracy of the permanent magnet synchronous linear motor dual‐axis control system. Finally, through the simulation and experiment of the dual‐axis motor platform, the effectiveness of the proposed contour error calculation method and the intelligent adaptive controller can make the dual‐axis motion control system have higher accuracy and strong robustness and can also make the motor run more smoothly. [ABSTRACT FROM AUTHOR]

To solve the problems mechanically caused by parallel direct‐drive permanent magnet motors (DD‐PMSM). This paper proposes a concave‐core stator direct‐drive permanent magnet motor (CCSDD‐PMSM) structure. In this study, an auxiliary yoke structure is proposed to optimise the magnetic circuit and analyse the cogging torque to achieve the minimum detent force. Based on the unit motor and combined with the magnetomotive force to analyse the symmetry of different winding distributions, the stability characteristics of the motor are studied. The magnetic field distribution of the motor load air gap is calculated using the finite element method. The contribution of different spatial order harmonics to the motor output torque is calculated using the Maxwell tensor method. The torque calculation expression of the CCSDD‐PMSM is given. Finally, an experimental prototype is made to verify the accuracy of the analysis in this paper. [ABSTRACT FROM AUTHOR]

The position sensorless permanent magnet synchronous motor (PMSM), with its simple structure, is applied in the aerospace field with high reliability requirements. To drive PMSM safely, the three‐phase current measured from the driver needs to be isolated for the closed‐loop control. And then, the accuracy current measurement is crucial for achieving optimal motor performance. In the paper, current transformer (CT) with centre taps is employed to isolate and measure the high‐frequency current of the inverter switch. Additionally, an algorithm is proposed to reconstruct the switch current into the low‐frequency phase current. Subsequently, the measuring method and the algorithm are applied to an inverter platform, which drives a 100W PMSM. Finally, the reconstructed phase current waveform is compared with the measured phase current waveform, and the experimental results show that the above method is effective and feasible. [ABSTRACT FROM AUTHOR]

The design and optimisation of a permanent magnet‐assisted synchronous reluctance (PMaSynR) traction machine is described to improve its energy efficiency over a selection of driving cycles, when installed on a four‐wheel‐drive electrically powered vehicle for urban use, with two on‐board powertrains. The driving cycle‐based optimisation is defined with the objective of minimising motor energy loss under strict size constraints, while maintaining the peak torque and restricting the torque ripple. The key design parameters that exert the most significant influence on the selected performance indicators are identified through a parametric sensitivity analysis. The optimisation brings a motor design that is characterised by an energy loss reduction of 8.2% over the WLTP Class 2 driving cycle and 11.7% over the NEDC and Artemis Urban driving cycles, at the price of a 4.7% peak torque reduction with respect to the baseline machine. Additional analysis, implemented outside the optimisation framework, revealed that different coil turn adjustments would reduce the energy loss along the considered driving cycles. However, under realistic size constraints, the optimal design solutions are the same. [ABSTRACT FROM AUTHOR]

In modern distribution networks, integration of distributed generations (DGs) at consumer premises is common. However, islanding detection in such a grid‐tied distributed generation (GTDG) network is the topmost challenge to ensure power quality and reliable operation. This paper presents a modified passive islanding detection scheme (MPIDS) for the GTDG network, using a One‐D recursive Median filter (ODRMF) algorithm. Firstly, at the point of common coupling (PCC), 3‐phase voltage is acquired. Next, the ODRMF is employed to extract 3rd harmonic and residuals from the acquired voltage signal. Afterward, two novel islanding detection indices developed are: (1) First change detection (FCD), which is calculated from the residuals, and (2) delta selected harmonic distortion (∆SHD), which is computed from 3rd harmonic content of the voltage signal. Finally, variations in the two indices are compared with the threshold to identify islanding. To validate the efficacy of the presented MPIDS, rigorous simulations in MATLAB/ Simulink are conducted on the UL‐1741 and IEEE 13‐bus GTDGs systems under different conditions. The results illustrate that the presented strategy is highly reliable in all assessed conditions and can detect the islanding as well as non‐islanding incidents effectively under balanced and unbalanced load/generation conditions with a very low non‐detection zone. [ABSTRACT FROM AUTHOR]

Given the existence of detent force, the positioning accuracy of permanent magnet linear synchronous motor (PMLSM) with an iron core worsens in its application in the field of the precision drive. To address this problem, a method is proposed to weaken the detent force of PMLSM with a V‐shaped tooth‐slot structure. The models of the detent force, including the cogging force and end force, are established theoretically. The analytical expressions of cogging force and end force are obtained by analysing the ripple rule of the motor. Then, the tooth‐slot surface of the motor with the V‐shaped tooth‐slot structure conducts infinitesimal processing. The relationship between cogging force, end force, and the V‐shaped depth of the V‐shaped tooth‐slot PMLSM is deduced, respectively, using the integration method. Furthermore, Ansoft finite element simulation software Maxwell module is used to compare the conventional PMLSM, V‐shaped magnetic pole PMLSM, and V‐shaped tooth‐slot PMLSM. The comparison reveals that the V‐shaped tooth‐slot structure has the excellent characteristic of increasing the average value of thrust while reducing the ripple of thrust caused by detent force. Finally, prototype fabrication and experiments are conducted to verify the correctness and feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes a novel fault detection method for Takagi–Sugeno fuzzy systems via multiple observer design and ellipsoidal analysis. By considering only one fault distribution matrix at a time, the original system is divided into a limited number of fault modes. For each fault mode, an observer with finite‐frequency fault sensitivity performance and full‐frequency unknown inputs robustness performance is designed to generate the residual signal. Based on the designed observer, the ellipsoidal analysis is used to evaluate a residual and to give a fault detection index for each mode. In addition, the fault detection result is provided by combining "or" logical operation of the multiple indices. Numerical simulations and an AC servo motor experimental platform are used to verify the viability and validity of the proposed method. [ABSTRACT FROM AUTHOR]

A sampling error‐based finite‐set predictive current control (FS‐PCC) is proposed in this article for the open‐end winding induction motor (OEWIM) drive. The proposed scheme controls the zero‐sequence current (ZSC) alongside the stator currents. In a model‐free approach, this method predicts the future of ZSC and stator current components by the stator current and voltage sampling errors. In this way, the parameters of the OEWIM are not utilised in the prediction algorithm of the FS‐PCC. So, the proposed method is robust against the variation of the parameter. Moreover, this article presents a simple vector selection technique for the FS‐PCC of the OEWIM. The proposed technique has two cost functions and a simple algebraic equation to put the voltage vectors (VVs) in the prediction algorithm. The first cost function uses VVs that do not have the zero‐sequence voltage component. Then, the algebraic equation determines VVs that must be utilised in the second cost function. Finally, the optimum VV is selected by the second cost function. In the proposed scheme, the prediction algorithm is iterated 14 times instead of 27 iterations of the conventional predictive algorithm. So, besides establishing a novel model‐free prediction algorithm, the proposed method has almost 50% fewer calculations. The validity of the proposed sampling error‐based FS‐PCC and the simplified vector selection technique has been verified through experimental tests. [ABSTRACT FROM AUTHOR]

In this paper, a calculation method is proposed for the radial suspension force of a bearingless motor with a surface‐mounted permanent magnet (SPM) rotor, a consequent‐pole permanent magnet (CPM) rotor, and a homopolar permanent rotor (HPM). The radial suspension forces are calculated mathematically and analytically using the airgap flux density. It was confirmed that the proposed radial force equations are practical to calculate the suspension force based on the airgap flux density. The CPM bearingless motor and bearingless AC HPM have salient pole rotors that interact with the 2‐pole Magnetomotive force (MMF) to generate 6‐ and 10‐pole components. As a result, the radial suspension force of the CPM bearingless motor is generated by 8‐ and 6‐pole, and 8‐ and 10‐pole magnetic flux, whereas the bearingless AC HPM produces the radial suspension force by DC and 2‐pole components. The shaft torque, the suspension force, and efficiency were also compared for SPM, CPM bearingless motors, and bearingless AC HPM. Consequently, the torque value of the CPM bearingless motor is quite close to SPM bearingless motor. Moreover, the suspension force of the CPM bearingless motor is quite close to bearingless AC HPM. [ABSTRACT FROM AUTHOR]

The bearing voltage brings premature failure of the motor bearings in the subway traction system, which is related to the stray capacitance of the motor. Therefore, the accurate calculation of stray capacitance parameters is of great significance for predicting bearing voltage. In previous studies, stray capacitances generally were acquired from simplified model of the motor. The effect of stator end‐winding and the bearing labyrinth seal on stray capacitance was usually ignored. In this study, the stray capacitance is analysed and the finite element calculation is carried out, and the improved finite element model of motor is proposed, which includes the end‐winding treatment and the bearing labyrinth seal. Then the feasibility of the improved model is verified by the measurement, and it is found that the accurate modelling of end windings has a great influence on the capacitance, and the bearing seal capacitance cannot be ignored while it is used in the motor. Finally, the influence of labyrinth seal parameters on the bearing voltage ratio of the motor is analysed, and it is concluded that the reduction of the radial gap width or the axial gap width of labyrinth seal can effectively reduce the risk of baring current. [ABSTRACT FROM AUTHOR]

High‐speed permanent magnetic machine (HSPMM) is attracting more attention due to its high power density, compact size, small rotating inertia, and rapid response capability. However, the design of the HSPMM rotor is a non‐linear, multi‐physics coupled process that makes it difficult to build an accurate mathematical model for optimisation. This study proposes a multi‐objective optimisation method based on the multi‐physics surrogate model (MPSM). This method uses an MPSM to replace the finite element model (FEM) for optimisation, which can effectively solve the problem of non‐convergence and time consumption of the traditional FEM in the optimisation process. Finally, a 1.1 MW, 18,000 r/min HSPMM is produced and related experiments are carried out; the feasibility of the method proposed in this study for HSPMM optimisation is verified. [ABSTRACT FROM AUTHOR]

Electrical machines are widely used in home appliances, the performance of which is mostly related to the quality function of the electrical machines. What has been used so far in home appliances brought with themselves a wide assortment of advantages and disadvantages. With the aim to overcome the drawbacks of the previously implemented electrical motors in washing machines, a new configuration of flux switching permanent magnet motor (FSPM) with the segmented outer rotor (SOR‐FSPM) is proposed benefitting from a direct driven drum. To reduce the cogging torque as well as torque ripple and to improve the total harmonic distortion, cutting the stator in a way to lower overlapping between the rotor and stator pole, inserting notches into the poles of the rotor to modify the air gap between the stator teeth and the rotor segments are proposed. The Taguchi method and sensitivity analysis are further applied to find the best combination set of changes in such a way to smoothen the chart showing reluctance between stator and rotor and fix the zero‐point crossing of the flux linkages in different rotor positions. Finally, the proposed SOR‐FSPM is prototyped, and experimental results along with the finite element method results are discussed and compared in order to verify the design process. [ABSTRACT FROM AUTHOR]

A method for achieving open‐phase fault tolerant operation of a dual‐inverter‐based traction drive with charging capability is presented. This method utilises a contactor to connect the switching nodes of the two half bridges which are normally used for AC charging in this dual inverter configuration. These half bridges are then modulated to provide a path for zero‐sequence current and enhance the available voltage vector space of the drive by injecting a controllable common‐mode voltage between the two inverters. A control method and five‐level modulator based on zero‐sequence voltage control and phase shifted carriers are introduced to accommodate this novel remedial method. Using this approach, the open‐phase faulted dual inverter drive is able to operate with twice the speed range of the conventional open‐phase fault tolerant approach, which is to provide a path for zero‐sequence current by connecting the negative DC rails of the two inverters with a contactor. Simulation and experimental results with a prototype dual inverter drive are presented to validate the theory of the new control and modulation method. The experimental results showcase the proposed algorithms performance by dynamically responding to an open‐phase fault and starting from standstill, thereby proving its validity for an electric vehicle application. [ABSTRACT FROM AUTHOR]

Although synchronous generators are robust and long‐lasting equipment of power plants, consistent electricity production depends on their health conditions. Static and dynamic eccentricity faults are among the prevalent faults that may have a costly effect. Although several methods have been proposed in the literature to detect static and dynamic eccentricity faults in salient pole synchronous generators (SPSGs), they are non‐sensitive to a low degree of failure and require a predefined threshold to recognise the fault occurrence that may vary based on machine configuration. This article presents a detailed magnetic analysis of the SPSGs with static and dynamic eccentricity faults by focusing on the external magnetic field. The external magnetic field was measured using two search coils installed on the backside of the stator yoke. Also, advanced signal processing tools based on wavelet entropy were used to analyse the induced electromotive force (emf) in search coils to extract the fault index. The proposed index required no threshold to recognise the starting point of fault occurrence and was sensitive to a low degree of fault. It was also non‐sensitive to load variation and noise that may induce a false alarm. [ABSTRACT FROM AUTHOR]

This study proposes a novel power supply system that utilises wind power to produce AC and DC power. A special designed generator based on bidirectional flux modulation effect is the key part of the proposed power supply system. The novel power system has a compact structure since the proposed generator has two electric port. There are three essential points that make the proposed system outstanding. One is the contra‐rotating rotors, which will cluster wind power even under low wind speed. Second one is the dual armature winding structure, which will provide AC and DC power simultaneously. There are two electric port in the proposed generator. One port can produce AC power to the non‐sensitive resistive load. The other can provide AC power with different frequency to the rectifier to obtain DC power. The induced voltage due to flux modulation effect can be used to offer AC power, and the induced voltage due to the outer rotor can be used to offer DC power. The voltage frequency of two sets windings is different. The last one is the air gap flux rotation speed amplification due to flux modulation effect. Time stepping finite element method is used to analyse the dynamic performance of the proposed machine. [ABSTRACT FROM AUTHOR]

High‐frequency audible noise and high‐frequency vibrations (HFVs) in electrical vehicles are primarily caused by vibrations and ripples generated in the traction motor. The appositeness of permanent magnet synchronous motors (PMSMs) has been boosting in traction applications due to their high energy density, compact size and high torque to weight ratio. A novel and step‐by‐step design of medium power, high speed, surface PMSM, suitable for e‐bus or e‐truck applications, with suppressed torque ripples, is presented. Initially, a conventional machine design approach has been used to design 100 kW PMSM. In the next step, the design has been ameliorated by making it a fractional slot winding machine to suppress the winding harmonics. Finally, the effect of the permanent magnet embrace size on the torque ripple has been investigated. A nonlinear relationship between the torque ripple and PMSM magnetic embrace has been developed. The developed relationship has been validated in the finite element model of the machine. Gradient‐based nonlinear sequential programming has been used to find out the optimum magnetic embrace for the minimised torque ripple. The effectiveness of the optimised design has been revalidated in the FE software. The step‐by‐step design process described here can reduce the torque ripple by 85% of optimised design compared to the conventionally designed PMSM. [ABSTRACT FROM AUTHOR]

In AC electrified railways, there is a significant exchange of power at fundamental and harmonics in quite dynamic conditions. Harmonic patterns of AC rolling stock and railway networks are analysed in terms of active and non‐active power flow, relating it to the characteristic of the network and to operating conditions, synthesised in the fundamental current intensity and speed. Herein, it is shown that correlation and clustering can separate distortion terms of internal and external origin also without a priori information. The use of harmonic power terms (product of voltage and current components) shows improved robustness with respect to the analysis of the voltage and current components alone. [ABSTRACT FROM AUTHOR]

This paper proposes an improved model based predictive torque control (MPTC) method based on positional error between reference and estimated stator flux vectors. The main advantages of the proposed method are: the improved computational efficiency which requires minimum hardware resources and weighting‐factor‐free cost function. Weighting factor is removed by using modified reference transformation, which converts torque reference into equivalent stator flux reference. Improvement in computational performance is achieved by using decreased number of voltage vectors for prediction. An admissibility criterion based on flux positional errors is introduced to reduce the number of voltage vectors. The computational time saved is utilised to incorporate extended Kalman filter for better estimation of flux and torque. The validity of the proposed method is tested on a two‐level three‐phase inverter fed induction motor drive with dSpace DS1104 as controller board. The dynamic response and computational cost of the proposed method is compared to other established MPTC methods. The superiority of the proposed technique is confirmed by experimental results, which show an average of 32% reduction in computational time when compared to conventional MPTC while comparable dynamic response in terms of torque ripple, flux ripple and load current harmonics, is also maintained. [ABSTRACT FROM AUTHOR]

To use photovoltaic energy, voltage source inverters are playing an important role. The most of local AC loads such as AC motors need higher voltage than solar panel output voltage. Differential boost inverter produces an AC voltage that is greater than the DC input voltage in a single power stage. This inverter consists of two DC‐DC bilateral boost converters in which work via time‐variant duty cycles to produce sinusoidal voltage, and this feature causes complexity in control design. To deal with this complexity, new modeling so‐called generalized averaged model is used to achieve a linear time‐invariant model. In this paper, a nested control loop is designed. This control strategy consists of two control loops in which the inner loop is designed by linear quadratic regulator theory to displace poles in proper location and the second loop uses a PI‐PR controller to track desired voltage and reject disturbances. To evaluate the proposed control method, the sliding mode controller is applied and compared as well. As shown by simulations, the proposed control strategy has more reliable performance and provides higher robustness in comparison with sliding mode control technique in rigid situations such as dealing with nonlinear load, parameters values changes, and external disturbances. [ABSTRACT FROM AUTHOR]

In this article, basic concepts, operating principles and important characteristics of continuous control set-predictive controllers (CCS-PCs) applied to AC motors are explained in detail. Based on the existence or absence of cost function as well as the method used to find the optimal control action, CCS-PCs can be categorised into the following three categories: predictive controllers without cost function, predictive controllers with a cost function (or model predictive controllers) and deadbeat controllers. To identify the advantages and disadvantages of each category, one of the recent algorithms of each category is selected and implemented experimentally. Then, various experimental tests are conducted where performances of all the algorithms are assessed in a comprehensive manner by evaluating stator-flux ripple, torque ripple, stator current harmonics, robustness against parameter changes, computational complexity, memory requirement and torque dynamic response. To achieve general and meaningful conclusions, the analysis is performed on a traditional three-phase two-level voltage source inverter used to control an interior permanent-magnet synchronous motor. Based on the theoretical discussions and experimental results, it is indicated that which category of CCS-PCs can be adopted in high performance AC motor drives. [ABSTRACT FROM AUTHOR]

Analysis of dynamic behavior of alternating current (AC) motors and their vector control has an important place in the education of electrical and electronics engineering at the graduate level. Generally, only theoretical education in engineering affects motivation of both educators and students negatively. Particularly, in graduate education, realization of subjects of AC motors in laboratory facility enables students to learn effectively. However, it may not be easy to implement because of establishing cost of a physical laboratory environment in universities. Therefore, by using visual software technology, engineering applications such as vector control of AC motors can be prepared in a simulation tool and students' active learning skills can be developed without any cost by means of visual simulation studies. Hence, in this study, an educational interface was prepared as a simulation for vector control of AC motors by using MATLAB GUI. In this application, two types of AC motors (induction motor and permanent magnet synchronous motor) and two types of vector control (direct torque control and field-oriented control) can be realized. In the simulation, after selecting motor and vector control type, determination of speed acquisition method and speed control method can be selected, and simulation study can be performed easily. Performance of selected motor type and control methods can be evaluated by using current, speed, torque, and energy consumed. In addition, to see success of the developed tool, it was used by the students at Ondokuz Mayis University, and at the end of lesson, a questionnaire was made and students' ideas were taken. [ABSTRACT FROM AUTHOR]

This paper presents a project‐based learning pedagogy for undergraduate mechanical engineering students which integrates traditional hardware‐based laboratory with LabVIEW to control the angular position, velocity, and acceleration of AC servo motors of a six‐degree of freedom manipulator. The proposed experimental modules have been proved to be very effective in assisting teams of undergraduate students within the Department of Mechanical, Materials and Manufacturing Engineering at the University of Nottingham, Malaysia Campus, who have used the modules in designing a new mechanical structure of a robot during their capstone design project. The proposed pedagogy inspired undergraduate students to publish their first paper based on the outcomes of their project. The focus on this paper is to present how the students' learning experience has been significantly enforced and their role in developing the modules introduced in this paper. Three modules are presented; the first configures a timer to generate a signal that drives the servo motors. The second drives the servo motor to a specific angular position with a constant angular velocity. Finally, the third is used to control the servo motor to follow any desired angular position, velocity, and acceleration. [ABSTRACT FROM AUTHOR]

A novel topology of the ac–dc power converter to supply neutral-point-clamped inverters used in ac motor drives and wind offshore power grids is proposed. It is based on the T-type multi-state switching cell, which allows obtaining a five-level voltage waveform downstream of the input filter inductor. The converter presents a high voltage gain due to the transformer secondary windings associated with series-connected diode rectifiers. Prominent main characteristics of this topology include power factor correction, operation of the filter inductor at twice the switching frequency, reduced conduction losses in the semiconductors, and voltage balance across the output capacitors. To verify the operating principle of the converter a design example is described, considering that the converter specifications are: output power of 3 kW; rms input voltage of 110 V; total output voltage of 1 kV, which is equally divided among four capacitors and switching frequency of 20 kHz. Simulation results are shown to validate the theoretical assumptions and verify the behaviour of the rectifier in terms of dynamic response while also supplying unbalanced loads. [ABSTRACT FROM AUTHOR]

Reliable and safe operation of electric motors in the industry is highly desirable. Accurate modelling is the first step in developing a diagnostic tool for different types of failures. This study presents a generalised dq-model for interior-mount line start permanent magnet synchronous motors under asymmetrical stator phase's windings. The presented dq-model has been derived using winding theorem. Implementation and simulation of the derived dq-model has been done using MATLAB/ SIMULINK software. For validation purposes, interior-mount line start permanent magnet synchronous motor (LSPMSM) under this fault condition is implemented using the JMAGTM-finite-element-based software. The performance of a 1-hp interior-mount LSPMSM motor under different loading levels and stator winding asymmetric conditions has been investigated using the simulated MATLAB and JMAG models. Simulation results of MATLAB and JMAG are in very good agreement and show that under asymmetrical stator winding condition, oscillations are obvious in the torque characteristics of the motor. In addition, the torque experience high oscillations at a steady state due to the asymmetry between stator phases. Finally, investigating torque frequency spectrum showed that they can be good signatures in diagnosing asymmetrical stator winding faults in interior-mount LSPMSM. [ABSTRACT FROM AUTHOR]

Induction motors (IMs) are widely used in agricultural, industrial, and commercial applications. Bearing faults are one of the most common causes of breakdown in IMs. Motor current signature analysis (MCSA) is becoming a popular tool for bearing fault detection because of its cost effectiveness and noninvasiveness. However, when a motor operates under low-load and lower load conditions, MCSA cannot be used to detect the bearing outer raceway fault because of the influence of the supply frequency component spectrum leakage, eccentricity harmonics, and other noises. In this paper, a new method for the fault detection of bearing outer raceway fault in IMs is proposed. The method is based on the analysis of the instantaneous frequency (IF) of the IM stator current using Hilbert transform, and Fast Fourier Transform (FFT) spectrum analysis is used to detect the frequency associated with the bearing outer raceway fault. The proposed method can significantly reduce the negative influence of the supply frequency component spectrum leakage, and thus can enhance the fault features to detect bearing outer raceway fault under low-load and lower load conditions, compared with the traditional MCSA method. Finally, the experimental results on an IM with bearing outer raceway fault prove the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the speed control issue for fully unknown Interior Permanent Magnet Synchronous Motors (IPMSMs). A full adaptive controller is proposed to control the speed of these motors while all physical parameters, adaptive variation bounds, and the load torque are unknown. Applying a four‐step backstepping strategy, which constructs the infrastructure of the whole controller design, and utilizing proper Lyapunov functions leads to generating proper adaptive control rules. The desired control performance is basically satisfied by rejection of the load torque and motor uncertainties. Optimizing the performance criteria, integral tracking error signals have been taken into account in the backstepping procedure in order to enhance the efficiency, robustness, and reduced steady‐state errors. The closed‐loop system stability is analyzed and proved utilizing Lyapunov and Barbalat lemmas. To evaluate the high performance of the designed controller, an illustrative example is simulated whereas the obtained results confirm the efficient treatment of the proposed method for the fully unknown system. The comparison of the simulation results with one of the recent papers in the literature verifies the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Since the three-dimensional (3D) analysis of linear induction motor (LIM) needs to consider the transverse end effect, the transverse magnetomotive force (m.m.f.) distribution model becomes significantly important. This study investigates the influences of different transverse m.m.f. models on operating characteristics of double-sided LIMs, and it also develops a novel m.m.f. model. First, four types of hypothetical distribution models are put into a 3D analytical method that considers the longitudinal and transverse end effects. Second, variations of the thrust, lateral and vertical forces with the models are comprehensively investigated in the possible operating regions. Besides, the calculated results are validated by finite elements method results and measurements in a prototype double-sided linear induction motor (DLIM). Finally, the model presented in this study can be considered as a kind of optimal model for analysing DLIMs, and comparisons with other models in each operating region are mentioned. [ABSTRACT FROM AUTHOR]

This study is for model predictive pulse-width modulation (PWM) for power electronics converters as AC motor drives. Compared with conventional PWM, model predictive PWM (MPP) employs the prediction model of PWM effect, and utilises the pulse arrangement freedoms to improve the performance of switching losses, current ripple and electromagnetic interference for the converter system. This study contains five parts including introduction, current ripple prediction method, variable switching frequency PWM, MPP for multi-level inverters and conclusions. The methods introduced in this study have been and can be applied in traction and industry motor drives. [ABSTRACT FROM AUTHOR]

SUMMARY This paper proposes new three-phase current control methods for AC motor drives, which detects only a phase current from among three-phase currents. The first proposed method first detects a phase current, and then estimates the two-phase current in the stationary reference frame using the detected single phase current. The second proposed method first detects a phase current, then synthesizes the two-phase quasi-current in the dq rotating reference frame, and finally produces two-phase current estimates by extracting the positive-phase component from the quasi-current. The third proposed method produces two-phase current estimates by filtering out the negative-phase component from the quasi-current. This paper presents the principles and detailed characteristic analyses of the proposed methods and validates them on the basis of extensive experiments. [ABSTRACT FROM AUTHOR]

An AC drive system is a multivariable, nonlinear, strongly coupled, and complex electromechanical system whose safety and reliability are extremely important in modern electric locomotives. Therefore, it is very important to carry out the converter's fault diagnosis. In this paper, the vector control of an AC motor drive system is modeled and simulated with MATLAB in order to obtain reliable failure data. Through comparative analysis, we extract the effective fault features, which are input to the neural network (NN) to complete the fault diagnosis. Finally, we compare the training and diagnosis results of the Levenberg-Marquardt (LM)-back propagation (BP) and BP NNs through simulation experiments and show that the LM-BP NN has a higher efficiency and higher diagnosis accuracy. Also, it does not fall into local minima and is suitable for pattern recognition. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper presents a method of multiobjective optimization design with anti-demagnetization aiming at the problem of irreversible demagnetization in high-density permanent magnet synchronous motors (PMSMs) due to temperature and external magnetic field, at the same time considering the volume of permanent magnets and cost, torque ripple, and core loss. In the first step, a two-dimensional magnetic network model is used to rapidly assess the basic design parameters and its ability to avenge the anti-demagnetization of the PMSM. In the second step, the finite element method (FEM) is used to design the key parts of motor, and regression models that solve the model of the multiobjective problem are built based on the simulation experiment data. On this basis, multiobjective optimization result using genetic algorithm is used that can achieve a fast and efficiently global optimal solution. [ABSTRACT FROM AUTHOR]

This paper proposes two new “disturbance observers in the D-module” for sensorless drive of synchronous motors including permanent-magnet synchronous motors and synchronous reluctance motors. The disturbance filter for the observers can estimate speed-varying rotor phase (in other words, rotor position) with zero phase lag. It is constructed by means of “the filter in the D-module,” which has the following desired characteristics for variable sensorless drive: (1) it makes distinction between positive and negative frequencies of two-phase signals; (2) it can allow processing of the signals based on frequency polarities; (3) it can also change dynamically its center frequency of bandpass filtering according to rotor speed estimates; (4) its passband and transition can be designed independently; and (5) it can be easily realized. The new disturbance observers also have a generality such that they contain the recently proposed disturbance observer as a special case. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(3): 63–70, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20602 [ABSTRACT FROM AUTHOR]

A permanent magnet synchronous motor (PMSM) with nonsinusoidal electromotive force (EMF) generates torque ripple even if the sinusoidal PWM inverter drives the PMSM. A new modified trapezoidal modulating signal for PWM inverter suitable for PMSM drive with nonsinusoidal EMF is proposed in this paper. A new modulating signal for the PMSM drive is determined by the condition of reducing torque ripple of the motor with various trapezoidal EMF. When the PWM inverter using modified trapezoidal modulating signal drives the PMSM having a nonsinusoidal EMF, the torque ripple of the motor can be reduced, the DC link voltage utilization is improved, and reduction of switching loss can be obtained. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 62–71, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20441 [ABSTRACT FROM AUTHOR]

The initial pole position must be estimated for speed sensorless vector control of PM motors. This paper presents a method to estimate initial pole position for Surface Permanent Magnet Synchronous Motors (SPMSM). For estimating the initial pole position, we utilize Fourier transformation for detecting the inductance change caused by rotor magnetic saliency. The six inductances, obtained by Fourier transformation of the voltage and current measured when a pulse voltage is applied to the motor armature winding respectively, will directly provide the exact information of pole position. The polar distinction is also carried out using Fourier transformation on the basis of the inductance change caused by magnetic saturation. Experimental results on a 0.3-kW 8-pole SPMSM demonstrate the validity of the proposed method. Although no machine was coupled with the tested motor, there was no change in rotor position during pole position estimation. In polar distinction, the maximum rotor position change was only 1.38 electric degrees. A method to estimate initial pole position without a motor voltage sensor is also discussed. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 47–53, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20307 [ABSTRACT FROM AUTHOR]

In this paper, the authors propose an induction type surface or planar motor for smooth two-dimensional drive including rotating operation. The secondary member is composed of the flat conducting plate without directional qualities and the back-iron plate as secondary yoke. The primary member is composed of the torodial core and the armature winding which can supply the current in every coil embedded in a slot. For the rotating drive, all the coils are used and the same rotating magnetic field as an ordinary rotating motor is generated. For the linear drive, a partial rotating field is generated in the direction of movement in each region separated into two groups every half of toroidal core. For the armature winding, two types of methods are used which are a ring-winding supplied current at each slot and a double-layer-winding supplied current to each coil. The two-dimensional electromagnetic analysis in Cartesian coordinate system is shown for the analysis, in which an effect of circular shape is considered as an edge effect. The thrust and normal force characteristics at standstill were confirmed practically by using test machine. It was cleared that the surface motor had high transformation rate of about 79% for thrust in spite of the circular shape. © 2000 Scripta Technica, Electr Eng Jpn, 130(4): 107–115, 2000 [ABSTRACT FROM AUTHOR]

Both low-speed wheel-on-rail and the medium- speed Maglev transport system with single-sided linear induction motor (SLIM) propulsion have been in practical application. This paper presents the method of optimizing the design parameters of SLIMs using the nonlinear optimization method. The optimization problem is formulated by the use of the design formulas taking into account the end effect, skin effect and airgap leakage, and the transformation method and the simplex method are applied to solve the problem. Seven parameters, such as the number of poles, the pole pitch and the stack height, are chosen as the independent variables. The output kW/input kVA, the maximum flux density in the core teeth, the temperature increase, the primary length, the stack height and the maximum thrust are selected as the constraint functions. The performance characteristics are estimated using space harmonic analysis as well as the approximate equations. The method is applied to the SLIM design for urban transit, and the maximum speed is about 70 km/h. AS me transformation methods, the interior point transformation and the exterior point transformation are compared from the viewpoints of accuracy and cPU time. The design is analyzed under several objetive functions, the primary weight, the input kVA and the cost of secondary materials. [ABSTRACT FROM AUTHOR]

The authors have already described the nine-phase inverter driving system providing both the triple three-phase voltage source inverter with 180-deg conducting period and the ac motor windings with triple three-phase construction. The nine-pulse inverter driving system used three small-capacity three-phase coupling reactors having special windings for current balance and reduction of higher harmonies. In addition, for voltage control, current balance, and waveform improvement, optimal PWM pulse patterns were applied to the six-phase inverter driving system using a three-phase coupling reactor to provide double three-phase construction. In the system based on the mode in the title, the PWM control was applied to the nine-phase inverter driving system described in the foregoing. The coupling reactors in the system balance the fundamental currents of three sets of three-phase inverters and also absorb higher harmonic voltages other than 18p ± 1 (p = 1, 2, ...) orders. The optimal pulse patterns found by the approach to make the performance index minimum using the Lagrange multiplier method can be applied to the PWM to reduce the higher harmonic currents greater than those calculated by the modulation method comparing the sinusoidal signal wave with triangular carrier signal. This system can have a larger capacity than the six-phase PWM inverter driving system in which coupling reactors absorb higher harmonic voltages other than the 12p ± 1 orders and also improve output current waveforms. In addition, the system includes the capacity of coupling reactors slightly larger than the six-phase PWM inverter driving system but enables operation with smaller torque ripples and electromagnetic noises in low- to high-frequency ranges. [ABSTRACT FROM AUTHOR]

Discusses the application of the vector-controlled inverter-induction motor systems. Means of obtaining the terminal voltage values of the motor without switching ripple distortions; Implementation of the current control for high-performance vector control; Average values of the stator current.