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This paper presents a comparison of an AC radial flux interior permanent magnet (IPM) motor with the distributed winding (DW) and concentrated winding (CW). From time to time, manufacturers of electric vehicles change the design of electric motors, such changes may include changing the DW into CW and vice versa. A change to the winding in a radial permanent magnet synchronous motor may lead to a change in motor parameters during motor operation and /or change in the distribution of the magnetic field and thermal circuit of the electrical machine. The electromagnetic analysis, efficiency map, mechanical stress, and thermal analysis of the machine with the DW and CW are presented in this paper. This article describes the advantages and disadvantages of selected stator winding designs and helps understand manufacturers' designers how the DW and CW play a key role in achieving the designed motor's operational parameters such as continuous performance. Analyzing the performance of both machines will help identify their advantages and disadvantages with regard to thermal phenomena, magnetic field and operational parameters of the presented IPM prototypes. Both prototypes are based on commonly used topologies such as 12/8 (slot/pole) and 30/8 (slot/pole) IPM motors consisting of magnets arranged in a V-shape. The AC IPM motor was designed for an 80 kW propulsion system to achieve 170 N·m at a base speed of 4 500 rpm. Modern CAD tools are utilized throughout the numerical computations based on 2-D finite element methods. Selected test data are used to verify and validate the accuracy of finite element models. [ABSTRACT FROM AUTHOR]

Conventional winnowing machines rely on manual operation and adjust their parameter settings based on experience. These problems have led to poor wind sorting results. In order to improve the sorting accuracy and efficiency of the tea winnowing machine, a double-layer automatically controlled winnowing machine has been designed in this study. Firstly, an automatic control system based on a programmable logic controller is established. Secondly, the AC motor control technology is used to achieve the automatic adjustment of the baffle position. The prototype tests show that the control input voltage of the vibrating feeder is 2 V for Lan tea and 1.5 V for pan-fried green tea material. The frequencies of the upper fan are 30 Hz and 25 Hz, respectively, while those of the lower fan are 35 Hz and 30 Hz, respectively. For Lan tea, the No. 3 baffle moves to the right by 5 cm, and the positions of the No. 5 and No. 6 baffles remain unchanged. The main outlet of the double-layer winnowing machine contains 3.72% impurities. As for pan-fried green tea, the position of the No. 3 baffle remains unchanged, the No. 5 baffle moves 5 cm to the right, and the No. 6 baffle moves 4.5 cm to the right. The main outlet of the winnowing machine contains 4.28% impurities. The experiments indicate that the double-layer winnowing machine is more effective than the single-layer one and can provide a reference for an efficient and accurate winnowing machine. [ABSTRACT FROM AUTHOR]

Energy prices are increasing due to the considerable growth of energy demand, which has caused an increasing rise in fossil fuels consumption. The use of renewable energy sources especially solar photovoltaic (PV) technologies for water pumping applications has been seeking attention from researchers. The motor is an essential element of the PV water pumping system. The control strategy of the motor-driven water pump fed by solar PVs can affect the system’s performance. Intelligent control strategies have been implemented in various systems to improve their efficiency. Due to the advancement of technology in the field of control theory, the use of AC motors for water pumping applications has become more widespread and efficient. Therefore, this work intends to make a review of the intelligent control strategies applied to AC motors used in PV water pumping systems. Different controller boards used for the implementation of control strategies are also presented. Accordingly, this manuscript aims to provide a quick reference on the optimized control strategies for researchers and engineers who are interested in the performance enhancement of PV water pumping systems based on AC Motors. [ABSTRACT FROM AUTHOR]

With the rapid development of network communication technology and computer technology, network control system has been applied in many different fields. Networked AC induction motor is controlled by a communication network to realize data transmission. This paper mainly studies the nonlinear control of induction motor based on network control system. In order to solve the nonlinear problem of AC induction motor, this paper adopts the method of the linear resolve coupling, and combined with the characteristics of the Internet, establishes the mathematical model of the AC induction motor, and considers the use of the system parameter perturbation to construct the mathematical model of the AC induction motor. Aiming at the problems of system parameter perturbation and network-induced delay in networked AC induction motor control system, the robust control of networked AC induction motor control system is studied. The experimental results show that the proposed control strategy can achieve asymptotic stability of the system with parameter perturbation under the action of the controller and can achieve asymptotic stability even with external disturbance. Compared with control strategies 1 and 2, the adjustment time of the speed waveform oversetting phenomenon is about 0.18 s and 0.26 s, and the adjustment time of the control strategy proposed in this paper is only 0.06 s. It is shown that the nonlinear control method of induction motor based on network control system can significantly improve the validity and stability of the system model. [ABSTRACT FROM AUTHOR]

In this paper, a novel high-temperature superconducting flywheel energy storage system (SFESS) is proposed. The SFESS adopts both a superconducting magnetic bearing and a superconducting alternating current (AC) homopolar motor. The superconducting AC homopolar motor has structural advantages in high-speed operation, however performance of the high-temperature superconducting (HTS) field coil is easily affected by the external magnetic field generated by armature windings in the process of flywheel charge and discharge, and should be paid attention. We established an electromagnetic-thermal co-calculation model of the HTS coil to analyze the coil characteristics in this application. Simulation results demonstrate that the magnetic flux density is small near the central region of the coil and is the largest at the edges of the coil. The temperature rise caused by the change of magnetic field distribution reduces the critical current density of the tapes and increases AC loss. Furthermore, we studied the grid connection control strategy of the SFESS, which adopts double closed-loop control and direct power control, and verified the feasibility of the control strategy by multi software real-time and dynamic co-simulation. Works in this paper give some guidance to further development of a 50 kW·h SFESS prototype. All the configurations of the SFESS, the method of calculating AC loss of HTS field coil, and the control strategy of the SFESS system could be extended to large commercial units. [ABSTRACT FROM AUTHOR]

With the wide application of inverter-fed motors (IFMs), it is necessary to monitor the groundwall (GW) insulation status to guarantee the reliable operation of motor drive system. This article first proposes a mathematical model of leakage current in IFM to analyze its time domain characteristics, and then an online GW insulation monitoring method is proposed based on the transient characteristics of leakage current. By using the initial oscillation amplitude, oscillation period, and attenuation time of leakage current, the phase, position, and severity of GW insulation degradation can be identified. The proposed method is validated using an IFM, and the experimental results agree well with theoretical analysis. [ABSTRACT FROM AUTHOR]

The interior permanent magnet synchronous motor (IPMSM) has a structure, in which a permanent magnet is inserted inside the rotor and cogging torque is generated in its structure. To solve this problem, various methods for reducing the cogging torque are being studied. The first method is to reduce the cogging torque by increasing the air-gap length by applying tapering to the rotor or stator core. However, in case of reducing the cogging torque above a certain level, the tapering application method may cause a decrease in output because the position and shape of the permanent magnet are restricted. The second method is to apply skew to the stator or rotor. This is the most reliable way to reduce the cogging torque, but the magnetization rate of the permanent magnet is low, so the manufacturability is low. In this article, we describe a rotor with rotational tapering that fuses the advantages of tapering and skew and offsets the disadvantages. The motor design used 3-D finite element analysis (FEA), and the validity of this article was verified by making the final model and comparing it with the simulation results. [ABSTRACT FROM AUTHOR]

Three phase inverters with switching frequencies above 100 kHz have recently become feasible thanks to the significant progress made in wide band gap (WBG) semiconductor technology. The main drivers behind the intense research and development of these ultrahigh switching frequency pulsewidth modulation (PWM) inverters are the extraordinary gravimetric and volumetric power densities that can be achieved. On the other hand, not as much attention has been devoted to the loads that these inverters supply, quite frequently consisting in ac motors. The impact of sub-MHz PWM and of the associated tens of nanoseconds range switching transients on motor terminal overvoltage, common mode currents, and losses are still to be discussed exhaustively. The authors have thus decided to investigate what happens to induction motors (IM) supplied by inverters having switching frequencies up to 350 kHz. After an introduction on WBG semiconductor devices, the article presents some interesting experimental observations conducted on a 1.1 kW four-pole IM fed by a silicon carbide (SiC) inverter. Further insight is provided by tests on a laminated steel toroid, supplied by a single-phase full bridge SiC inverter. Discussions on the experimental results highlight the previously unreported impact of common mode losses, which become a predominant part of the PWM harmonic losses. [ABSTRACT FROM AUTHOR]

The winding segmented permanent magnet linear synchronous motor (WS-PMLSM) generally adopts three-phase windings and the length of the segment is greater than that of the passive mover. This article proposes an innovative design for the module motor, using two-phase integrated single-layer concentric distributed windings, no half-filled slots, and the influence of the pulsating magnetic field generated by the segmented windings is negligible. By analyzing the transition of the segment winding, a variable parameter mathematical model is established, and proportional resonance (PR) control is introduced to eliminate the influence of parameter changes on the model. Meanwhile, the concept of a multiphase motor is introduced for pass-through segment control, with the help of the double $\alpha $ – $\beta $ coordinate transformation method, a new effective coil selection and switching algorithms is constructed, and the thrust forces for the pass-through section are obtained. It is experimentally confirmed that this design is in line with the production. [ABSTRACT FROM AUTHOR]

A novel traction AC motor is proposed by grouping magnets and coils in the stator design with aluminium as substantial for the housing of stator and end ring. The stator back iron is designed with silicon steel. As a result, the magnet can provide more repulsion when revolving the rotor, lowering the input side current. The configuration of the motor was changed to increase its effectiveness in terms of efficiency, and its performance appearances were investigated to compare it to the traditional design of motor. Magnet software was used to simulate the novel constructed induction motor. Most of the factories depend on this induction motor for its significant impact on industrial production and being an essential component of the plant for developing countries' economic development. Using motor solver software, this paper examines the performance characteristics of a novel constructed induction motor, including efficiency, power factor, and losses. The output of the developed induction motor is compared to that of a traditional three-phase 2.2 kW induction motor for traction application using a motor solver. [ABSTRACT FROM AUTHOR]

A laboratory modeled dryer fully automated was fabricated for monitoring and controlling the drying of agricultural products. Instrumentations were installed for monitoring the rate of moisture remover using Aluminum Load Cell, interfaced to a personal computer at an interval of 30 seconds. A voltage/frequency AC motor speed controller for air flow rate, temperature controller thermocouples were installed for monitoring the temperature at 8 different points on the sample tray which were later logged and displayed on a personal computer via the thermocouple Logger. Five treatments of the cassava mash samples in three replicates were dried and monitored within the automatic control dryer. The result of the evaluation for drying kinetics of Industrial Cassava mash shows that, the system allowed the modeled dryer to operate at a constant temperature with desired airflow and also provided full control of the temperature and drying airflow. It also gave room for computerized real-time automatic control system to retain quality. The automatic control system was reliable for operation and easy maintenance. [ABSTRACT FROM AUTHOR]

Unavoidably, the controlsystem of any permanent magnet synchronous motor (PMSM) is subjected to perturbations, e.g., motor nonidealities and inverter nonlinearities. To reject these perturbations, a new super-twisting (ST) control variant, called speed adaptive super-twisting (S-AST) control, is proposed in this paper. In the S-AST control, a proportional-integral (PI) and a ST controllers are merged using an adaptive law that is based on the motor speed measurement. This is done to reduce the chattering problems that the standard ST control presents. In addition, a mathematical design for the S-AST control is proposed, where the relationship between the chattering amplitude, the switching frequency and the system perturbations is shown. The main contribution in this paper is the application of the S-AST controller to reduce the total harmonic distortion (THDi) of the PMSM currents. By comparing the S-AST control against PI control, the THDi is reduced from 9.9% to 1.27%, in simulation, and the THDi is reduced from 22.79% to 1.56%, experimentally. These results demonstrate how the S-AST control is an excellent alternative to improve the waveform of the PMSM currents. [ABSTRACT FROM AUTHOR]

Dual three-phase permanent magnet synchronous machines (DTP-PMSMs) have received increasing attention from the industry and academia due to their advantages in lower burden on power inverters when operating in high power applications compared to the three-phase counterparts and low torque ripples. In this article, it reveals that the favorable low torque ripple characteristic of DTP-PMSM is undermined in the high power and overload operating mode. To solve this problem, this article proposes a novel torque ripple suppression strategy based on optimal harmonic current injection. A mathematical torque ripple model of DTP-PMSM considering the cross-coupling effects between d–q axis and dq-z1z2 axis is built. And based on this model, a detailed analysis is carried out to obtain the optimal harmonic current. The theoretical analysis also guarantees that the induced machine loss is minimum. Moreover, the proposed strategy has good dynamic performance since the algorithm involves no iterative computation and is computationally effective, which is proved on a laboratory DTP-PMSM system. The effect of parameter variation is also discussed and tested. The experiment results prove that the influence of magnetic saturation on torque ripple can be effectively suppressed. [ABSTRACT FROM AUTHOR]

In the paper an original approach to efficiency map optimal synthesis is presented. A permanent magnet motor, working as controlled AC motor of synchronous type (PMSM), is selected as a case study. The first target of this research is to derive a lumped-parameter model of the motor (low-fidelity model), validated by magnetic field analysis (high-fidelity model). In turn, the end target is these two models application in a cost-effective optimisation procedures, where the goal is to identify the motor geometry maximizing the map area which is encompassed by a prescribed value for the motor efficiency. [ABSTRACT FROM AUTHOR]

This article presents the results of experimental studies of asynchronous motors with a short-circuited rotor (induction motors—IM) with the most common frequency control methods: scalar; vector control; vector with speed control circuit; scalar control with dynamic compensation. The purpose of the experiments was to identify and show the features of the reaction of these control methods to the stepped sketches of the load on the asynchronous electric drive, as in a nonlinear electromechanical system. When selecting the parameters and settings of the "Schneider electric" frequency converter settings, standard instructions and techniques have been used, so the settings of the regulators were not optimal. The aim was not to determine the most effective structures and show fundamentally new solutions. Asynchronous electric motors are substantially nonlinear structures. In the formation of vector control theory, a number of simplifications and assumptions were used, the cost of which was not very clear and theoretically difficult to assess. This work is a step towards estimating the cost of these simplifications. This paper provides the results of experiments in which step-loading modes are presented by the maximum possible registered signals and the amplitude of the stator voltage, formed by various algorithms, the frequency and amplitude of the rotor current and the actual sliding and rotation speed of the engine rotor. This made it possible to maximally objectively assess the effectiveness of the interpretation of asynchronous electric drives and the methods of their regulation. The authors have conducted research in this area for about 15 years. In numerous articles on this subject over the past 25–30 years, the authors did not find such results. The vast majority of work devoted to the study of asynchronous electric drives with frequency control uses the notion of not too significant errors in the linearization of Park's vector equations. In particular, the concepts of the sinusoidality of currents and voltages in AC motors and the accuracy of vector equations are almost always used, which are valid only at a constant frequency of the stator voltage. [ABSTRACT FROM AUTHOR]

A turbo-electric generator has been placed on the exhaust port of the petrol and diesel engines to investigate the possibility of recovering energy from the exhaust gas. Turboelectric generator is a combination of a turbocharger and a generator. The aim of the study is to find the possibility and effectiveness of the turbo-electric generator for recovering the energy from the exhaust gas of an engine. The test has been conducted on the two engines, i.e. first one is TD 202 small test engine bed (diesel engine) and another one is Honda CG125 cc (petrol engine) motorcycle. Two types of motor i.e. DC motor and AC motor have been used as generators by altering the way a motor works. Firstly, a DC motor is used as a generator in the turbo-electric generator for both test engines. The results show that turbo-electric generator recover less than 1% energy of the exhaust gas for both engines when a DC motor is used as a generator (TD 202 and Honda CG125 cc motorcycle). But in case of Honda CG125 cc motorcycle, the percentage of recovering energy is comparatively higher than the TD 202 test engine. The experiment is further extended by using an AC motor as a generator only for the Honda CG125 cc motorcycle. The results show better energy recovering from exhaust gas through turbo-electric generator, which is more than 1% of exhaust gas. The results reveal that the engine speed and the mass flow rate of the exhaust gas play a major role in harvesting the energy from the exhaust gas. Moreover, it is found that the turbo-electric generator module provides good efficiency when an AC motor is used as a generator in the module. The experimental results have been compared with available literature. [ABSTRACT FROM AUTHOR]

This paper proposes a phase current reconstruction strategy based on a dc bus using a single current sensor for a surface permanent magnet synchronous motor (SPMSM). The method of a single current sensor reduces the number of mechanical hall sensors and shunt resistors by using a modified current reconstruction algorithm. The information of rotor position is estimated by the sliding mode observer for its rapid response and strong anti-interference ability, and the observer needs to detect voltage and current components from α − β coordinate system. In order to reduce the buffeting problem of sliding mode observers, an adaptive neural network is introduced, by the way of extracting angle speed estimated values from sliding mode observers, and these values are trained to obtain the compensate angular velocity and minus index value to suppress speed value. The performance of this sensorless speed regulation strategy in the high-speed region using a single current sensor with an optimized adaptive neural network is verified and evaluated by PSIM simulation and experiments. [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]

This work describes a frequency-dependent bearing voltage model for squirrel-cage induction motors. Previous research related to bearing voltages commonly considered the bearing voltage ratio (BVR) as a constant. However, it is important to analyze the frequency-dependent behavior of the BVR when dealing with systems excited by high-switching-frequency pulsewidth modulation voltages. First, we measure the BVR characteristic for a 1.5-kW test motor. The measurement data show that, in the mid-frequency range (100 kHz–6 MHz), the BVR values are smaller than the conventional low-frequency constant value, and at higher frequencies, the BVR value increases above the low-frequency value. Considering this BVR characteristic, an equivalent circuit has been built and analyzed from the perspective of the BVR. The proposed equivalent circuit has been verified by comparing simulation data with measurement data. Based on the analysis results of the equivalent circuit, a parametric study was done to examine the effects of motor system parameters on the bearing voltage. For the study, variations of the bearing voltage on the changes of the input voltage waveforms and the winding-to-stator capacitance are analyzed by using measurement and simulation data. [ABSTRACT FROM AUTHOR]

AC motor drives fed from current-controlled power electronic converters are popular on account of their superior steady-state and transient performance. Hysteresis control is a popular current control technique, which needs modifications to compensate for its demerits. Appraisal of current error as a space phasor for implementing the hysteresis controller is one such modification. Current error space phasor (CESP)-based hysteresis controller for voltage source inverters-fed motor drives are capable of achieving superior dynamic performance. With the modified hysteresis current controller, the drive operates at a constant switching frequency and ensures an optimal switching vector selection. This article presents the analysis of CESP for a space vector-modulated indirect matrix converter (IMC). The modified algorithm for space vector modulation of IMC accommodates for the variations in dc-link voltage since CESP is input voltage dependent. The boundary for the hysteresis current controller is calculated from the computed values of CESP. The time-varying nature of the hysteresis boundary ensures a constant switching frequency operation for IMC. Thus, a CESP-based hysteresis controller is proposed for the vector control of the IMC-fed permanent magnet synchronous machine (PMSM) drive. Experimental results are presented for validating the performance of the proposed controller. [ABSTRACT FROM AUTHOR]

This article proposes and implements a novel wireless power and drive transfer system using orthogonal bipolar couplers and separately excited modulation (SEM). Specifically, two bipolar coils are orthogonally integrated and naturally decoupled to form a compact magnetic coupler which will be utilized in the transmitter and receiver, respectively. The key is to employ the SEM to alternatively energize bipolar coils in the transmitter while self-driven circuits in the receiver can directly extract the drive information to control receiver-side switches. Consequently, the concurrent wireless power transfer and wireless drive transfer can be skillfully realized via the shared transfer channel at the single resonant frequency. Moreover, the proposed system can effortlessly achieve the wireless dc motor drive with the capability of bidirectional motion, or the wireless ac motor drive with the variable-voltage variable-frequency control. Besides driving the dc and ac motors, a 200-W prototype is constructed with the transmission efficiency of 89.5% over the transfer distance of 100 mm for a resistive load of 40 Ω. Both theoretical and experimental results are provided to validate the feasibility and flexibility of the proposed system. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, an innovative approach to matrix-converter-based AC-–AC variable frequency drives (VFDs) is introduced. The possibility of using AC–AC matrix VFDs for reactive power compensation in conventional AC–DC–AC VFD-loaded power distribution lines is investigated. It is found that the interaction of a large number of conventional AC–DC–AC VFDs with a conventional capacitor-based local compensation device leads to overcompensation in 0.4 kV power distribution lines. This is due to the fact that the conventional compensation device is designed to compensate the lagging reactive power produced by inductive loads, such as AC motors. This highlights the demand for the compensation of leading reactive power that is not predicted by the designer. To solve this problem, the modification of a certain number of previously installed VFDs by replacing their conventional AC–DC–AC converters with AC–AC matrix converters is proposed. This can lead to improvements in the power factor in 0.4 kV power distribution lines. In this study, the range of reactive power produced by conventional AC–DC–AC VFDs was determined mathematically, by simulation, and experimentally. The range of reactive power produced by the novel AC–AC matrix VFD was also determined. On that basis, the number of VFDs to be modified is defined to keep the power factor close to unity. [ABSTRACT FROM AUTHOR]

This paper proposes an extended structure of a programmable low-pass filter (PLPF) for direct filtering of three-phase variables in automotive AC drives. The PLPF adjusts its cut-off frequency according to the synchronous frequency of the AC motors. Moreover, it compensates gain attenuation and phase delay of the fundamental component signal. The conventional PLPF can only be applied to variables in the stationary reference frame. In order to obtain filtered three-phase variables, an inverse reference frame transformation is required. However, the extended structure, which includes reference frame transformations, can be directly applied to three-phase variables and remove the noise in the earlier stage before transformation. The extended PLPF is more useful for making signal flows clear and intuitive when organizing an algorithm that directly requires three-phase variables. The extended PLPF requires a moderate computational load corresponding with that of the conventional PLPF because its formula is simplified by use of Kirchhoff's law. The reduction in the execution time is critical for implementing the filter based on low-cost microcontrollers. Using case studies, dead-time compensations and open-phase fault detection for AC drives show the effectiveness of the extended PLPF. [ABSTRACT FROM AUTHOR]

Copyright of Electric Drive is the property of Electric Drive Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article proposes and implements a brand-new wireless power and drive transfer (WPDT) system using wireless switches. A wireless piping network is conceived especially for pipeline transportations and in-pipe robots desiring wireless motor drive. Also, a multifrequency resonant network is newly explored to generate the variable-frequency-modulated magnetic fields where the wireless switches can extract the drive information directly. Differing from single-frequency T-circuits, this multifrequency network can offer different resonant frequencies which are not only coupling-independent but also large-scale load-independent. Importantly, it can realize both the power self-equalization and zero-phase-angle operation in transmitter and receiver circuits. To conduct the conceived WPDT, the magnetic resonant modulation is used to control the wireless switches automatically at the receiver side, thus flexibly enabling the bidirectional motions of dc motor and the variable-frequency speed control of ac induction motor. The experimental system efficiency can reach 83.5% based on a 200-W prototype at a 130-mm distance. Both theoretical analysis and hardware experimentation are given to verify the feasibility of proposed WPDT system for wireless piping networks. [ABSTRACT FROM AUTHOR]

Five-phase induction machines are attractive due to inherent benefits such as lower current rating than three-phase ones. On the other hand, ac motor drives often need to operate in the overmodulation (OVM) region, e.g., to increase the maximum speed or to work with reduced dc-link voltage. Most of the existing OVM strategies for five-phase drives are based on injecting low-order harmonics in the no-torque xy plane while avoiding low-order α−β harmonics (at least up to a modulation index of 1.2311 p.u.), so as to prevent the torque ripple associated with the α−β components. However, in practice the x−y impedance is very small, and hence, this approach can easily lead to overcurrent. This article proposes an OVM method for five-phase induction motors that adaptively modifies the injected components so that at each moment the addition of low-order x−y harmonics is favored over α−β ones but without surpassing the maximum current rms of the drive. In case the total stator copper loss (SCL) tends to exceed its rating during OVM in a given scenario, the proposed scheme automatically reduces the x−y injection to keep the SCL at its rated value. Experimental results verify the theory. [ABSTRACT FROM AUTHOR]

This paper focuses on the evolution of instantaneous supplying current absorbed by an AC motor used to drive a lathe headstock gearbox during a transient regime characterised by a strong acceleration and deceleration and a strong variations of the absorbed active electrical power (with positive and negative power flows). A relationship between the current root mean square and active electrical power evolutions was established and proved in experimental terms. A severe limitation of the electrical current evolution was revealed: the impossibility to describe a negative flow of absorbed electrical power. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One of the most important requirements for good dynamic behaviour of the feed drive is high acceleration of the CNC machine tool slide due to the demand for minimal mechanical time constant. The servo drive is one of the most important parts of every CNC machine tool. Generally servo drives for CNC machine tools have a very simple kinematic structure. But the optimal servo drives design is a problem which consists of an appropriate selection of AC or DC motors and mechanical transmission elements, which must satisfy some conditions as a system. Because of the extensive calculations and optimization algorithms, original computer programs are developed. The created programs for servo motor selection and optimization of the feed drives mechanical transmission structure enable an efficient interactive and optimal design of CNC machine servo drives. The presented software also reduces the design time and modernizes the design process. [ABSTRACT FROM AUTHOR]

A predictive current controller is established based on the system model and, therefore, suffers from the problems, such as parameter mismatches, digital delay, and external disturbances. In order to tackle these problems, an observer-based robust predictive current control strategy is proposed in this article, which employs an extended state observer to estimate the disturbances, currents, and applies the augmented system model for the design of the controller. It is generally formulated and applicable to any ac motor drive system as long as the prerequisites are satisfied. Furthermore, the proposed control scheme is proven to be input-to-state stable with a proper design of the controller and the observer. The effectiveness of the proposed control strategy is moreover verified with numerous experiments on a dSPACE system under various test scenarios. The comparative studies between the proposed method and the predictive current control approaches, i.e., the conventional deadbeat control and the continuous control set model predictive control, are conducted at different operating conditions. [ABSTRACT FROM AUTHOR]

A soliton is a unique wave that maintains its shape and constant velocity. It has been observed widely in natural nonlinear systems. In particular, a magnetic soliton has been observed experimentally on a nonlinear LC ladder circuit array. The aim of this article is to excite a magnetic soliton on the LC ladder circuit array using a permanent-magnet-flux-biased (PMFB) inductor. Electromagnetic analysis reveals that the PMFB inductor has exponential inductance characteristics due to the effective use of magnetic saturation in the stator core. Four PMFB inductors with different magnetic circuit topologies are analyzed and compared, to decrease the inductor current. Finally, this article numerically solves the loop equation for the LC ladder circuit array and shows that the magnetic soliton is successfully excited and propagates without changing its shape and velocity. This technique is equivalent to a rotating magnetic field and has a great potential in developing new ac motors or actuators. [ABSTRACT FROM AUTHOR]

This letter addresses experimental validation of the reduced-order natural speed observer design for position sensorless drive with nonsalient permanent magnet synchronous motor. The natural speed observer and the active flux estimator are connected in a cascaded fashion, which results in a simple sensorless algorithm that needs only to tune one bandwidth parameter for flux estimation and one bandwidth parameter for speed observation. Experimental results of high speed reversal test, zero speed stopping test, and slow speed reversal test are included, where the practice of applying nonzero $d$ -axis current at zero speed has shown to be effective for loaded zero speed stopping test, but it causes zero-speed locked-up at slow speed reversal with acceleration rate of $\rm \text{50}\,r/\text{min}/s$. Four remedies are compared to improve the slow speed reversal test and the proposed method gives almost ramp actual speed waveform, nondiverging $q$ -axis current and smooth transition in position waveform during slow zero speed crossing. A new dynamic expression of the active flux is proposed and with the aid of the active flux concept, the proposed sensorless algorithm is also applicable to various types of ac motors. [ABSTRACT FROM AUTHOR]

The cylinder head assembly from a GDI engine was separated to build a GDI fuel injection system capable of controlling the rail pressure and fuel injection levels. The GDI fuel injection system is driven by a three-phase AC motor with a direct connection between the camshaft and the motor. The operating conditions of the GDI fuel injection system are equivalent to those of actual engine driving. The AC motor drives the GDI high-pressure fuel pump by rotating the engine camshaft. In the GDI high-pressure fuel pump (HPFP), fuel is pressurized on the upward stroke of the plunger and pumped to the fuel rail. Fuel rail pressure (FRP) control is possible by controlling the opening/closing timing of the HPFP's pressure control valve (PCV), the fuel injection duration and the camshaft speed. In order to calculate the fuel injection rate characteristics of the GDI injector statistically under fixed conditions of the camshaft speed, FRP, and injection duration, the measurements of the fuel injection rate were repeated at regular time intervals. To calculate the variation of the fuel injection rate, the S/N (signal-to-noise) ratio, which is the average FRP divided by the FRP standard deviation, was calculated. A fuel injection rate was obtained under 88 experimental conditions combining the three conditions of the HPFP's PCV opening/closing timing, fuel injection duration, and camshaft rotational speed. The smaller S/N ratio shows the larger FRP variation. Also, it was identified that the S/N ratio is related to the variation of the fuel injection rate. [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]