Line-start Permanent Magnet Synchronous Motor Research Articles

Durum İzleme ve İstatistiksel Süreç Kontrolü Kullanarak Şebeke Kalkışlı Daimi Mıknatıslı Senkron Motorda Rulman Arızası Tespiti

Line start permanent magnet synchronous motor (LSPMSM) is used in many applications in industrial environments such as belt systems and fan systems due to its high efficiency, high power factor and self-starting features. Early detection of LSPMSM failures will eliminate production losses and high maintenance and repair costs. In this study, SCADA-based online condition monitoring and fault detection method is proposed for detecting bearing failures of LSPMSM. For this purpose, SCADA based condition monitoring automation was carried out primarily to monitor motor current and voltage data. The normal operating limits of the motor were determined by analyzing the current signals monitored under different speed and load conditions from a healthy LSPMSM with an exponential weighted moving average (EWMA) based statistical process control method. Then, fault detection was made according to the exceeding of these limits by using EWMA data of the current signals of a the LSPMSM in case of faulthy. The obtained results showed that the designed SCADA automation has the ability to collect and save data safely, and the proposed fault detection method is a successful tool for the detection of bearing failures of LSPMSM.

Stator Faults Modeling and Diagnostics of Line-Start Permanent Magnet Synchronous Motors

In this article, the occurrence of stator faults in line-start permanent magnet synchronous motors is analyzed. A dynamic model of the motor was developed in MATLAB/Simulink, which considers the performance of the motor both in healthy conditions and under the occurrence of interturn short-circuit faults, at an early stage of development. To validate the presented approach, simulation results, covering the full range of operation, and different fault severity levels, are compared with the motor experimental performance. The output of the proposed model, namely voltages and currents, present a good agreement with experimental results, demonstrating the accuracy of the proposed model. Additionally, an online fault diagnostic technique is explored, demonstrating its potentiality.

Optimization of Low-Power Line-Start PM Motor Using Gray Wolf Metaheuristic Algorithm

The paper presents the optimization method and computer software for the design of a low-power line-start permanent magnet synchronous motor (LSPMSM). The in-house-developed computer software was created with two independent modules: (a) the optimization procedure and (b) the numerical model of the motor. The optimization procedure used was a metaheuristic optimization method based on the gray wolf algorithm. Four design variables linked to the rotor structure were selected. The optimization process was performed from the rotor of a low-power induction motor (IM). The prototype of the motor (LSPMSM) was then built. The experimental measurements were performed for base the IM and optimized LSPMSM. The results of the measurements were compared for both motors. The experimental results confirmed the better performance of the designed motor in comparison to the induction motor.

Comparative analysis of line-start permanent magnet synchronous motor and squirrel cage induction motor under customary power quality indices

Super premium efficiency (IE4) line-start permanent magnet synchronous motor (LSPMSM) is one of the good alternatives to the squirrel cage induction motor (SCIM), especially for a line-start application. Motor performance parameters like efficiency, input power consumption, power factor, starting behavior and torque ripple are affected primarily because of the customary power quality indices. The problems originate due to furnaces, power electronic converters, nonlinear loads, digital controllers, modern electrical equipments and lively load variations. Hence, the performance analysis of LSPMSM and SCIM is essential to understand the motor behavior. Voltage harmonic distortion, voltage unbalance factor and long-duration voltage variation are considered in this study. Customary power quality indices (CPQI) are collected using power and energy analyzer in a sugar industry at various measured points. In the present study, 2.2 kW LSPMSM is designed and prototyped for constant load operation. The designed motor and SCIM are used for analyzing the performance using finite element analysis under the influence of measured CPQI and the effects on its individual performance parameters.

Analysis of the Synchronization Process and the Synchronization Capability for a Novel 6/8-Pole Changing LSPMSM

This article presents a novel 6/8-pole changing line-start permanent-magnet synchronous motor (LSPMSM) for improving the starting and synchronization capabilities. A 6/8-pole changing stator winding with simple structure, convenient switching, and speed detection capability is designed and studied. The synchronization process, which follows the 6/8-pole winding switching process, is analyzed. The effects of the switching speed, switching phase difference, and the rotor resistance on the synchronization process, respectively, are studied. Moreover, on the basis of the improvement of the starting capability utilizing the pole changing starting strategy, the rotor resistance is appropriately designed smaller to simultaneously balance the synchronization capability. The larger maximum moment of inertia that the motor can pull into synchronization validates the analysis. Through processing, both starting and synchronization capabilities have been improved for the proposed 6/8-pole changing LSPMSM compared with the conventional 8-pole LSPMSM.

Analytical Modeling for Optimal Rotor Shape to Design Highly Efficient Line-Start Permanent Magnet Synchronous Motor

In this study, an analytical technique for the rotor geometry optimization based on lumped magnetic parametric approach is used to design a two-pole, three-phase, 7.5-kW line-start permanent magnet (LSPM) synchronous motor. The permanent magnet shape substantially affects the air-gap flux density distribution, back electromotive force (EMF) as well as the copper loss, which have a great impact on the performance characteristics of the permanent magnet synchronous motors. Principal advantages involve in adjusting the rotor shape are to achieve the effective air-gap flux density and optimize the fundamental component of the back EMF with low harmonic content for minimum ripple torque. Therefore, to enhance the efficiency (η) and power factor, an optimized slot shape considering various design parameters is selected for the permanent magnet of the rotor in the prototype LSPM machine. A linear saturated lumped magnetic parametric model is developed to exhibit magnetic characteristics, and analytical equations are acquired under the open-circuit condition without considering the slotting effect for design simplicity. The influence of design variables on the air-gap flux density distribution and the flux leakage is investigated precisely using an analytical circuit model. A parametric study of the prototype model demonstrates that the steady-state performance of the LSPM motor are significantly influenced by the design variables. The inductance saliency ratio and electromagnetic torque components are carefully analyzed in terms of their effects on the load characteristics of the LSPM motor in order to determine the optimal shape of the PM slots and the magnetic flux barriers. The validity of the proposed method has been checked by evaluating the numerical solution of the analytical model using a two-dimensional finite element method.

Energy Efficiency Analysis of Fixed-Speed Pump Drives with Various Types of Motors

The paper presents a comparative analysis of energy consumption by 2.2 kW electric motors of various types and energy efficiency classes in the electric drive of a pump unit with throttle control in a water supply system. Line-start permanent-magnet synchronous motors of the IE4 energy efficiency class and induction motors of the IE4 and IE3 energy efficiency classes of various manufacturers were considered (IE4 and IE3 are labels of energy efficiency classes of electric motors according to IEC 60034-30-1 standard). Energy consumption at a hydraulic load changing under a typical duty cycle was calculated based on the nameplate data of the pump and electric motors. The developed method shows that selecting an electric motor based on the IE energy efficiency class under the IEC 60034-30-1 standard (i.e., based on efficiency at a rated load) may not provide the minimum energy consumption of a variable flow pump unit over a typical duty cycle. In particular, the considered IE4 class line-start permanent-magnet synchronous motors do not provide significant advantages over IE4 class induction motors, and sometimes even over IE3 class induction motors when they are used in variable flow pump units.

Influence of voltage unbalance on the steady‐state performance of line start permanent magnet synchronous motors

AbstractThe line start permanent magnet synchronous motor (LSPMSM) can be used for direct‐on‐line (DOL) starting, so it is easily affected by voltage unbalance. Based on the finite element method (FEM) and analytical method, the influence of voltage unbalance on the steady‐state performance of LSPMSM is studied in this paper. A two‐dimensional finite element model is built, and the armature current, losses and torque ripple as a function of the phase voltage unbalance rate (PVUR) are obtained. The influence mechanism of voltage unbalance on the steady‐state performance of a motor is demonstrated. Finally, a prototype of LSPMSM is manufactured and tested. By comparing the experimental data with the simulation data, the accuracy of the calculation model is verified, and the correctness of the research is proved. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Mathematical Modeling, Simulation and Experimental Testing of Interior-Mount LSPMSM Under Stator Inter-Turn Fault

Accurate modeling is the first step in developing a model-based diagnostics tool for different types of failures in electric motors. In this paper, a mathematical model for an interior-mount line start permanent magnet synchronous motor (LSPMSM) under the stator inter-turn fault is developed based on the principles of magnetic coupled circuit theory, electromechanical energy conversion and reference frame theory. The developed mathematical model is simulated using MATLAB and experimentally validated using a 1-hp, 4-pole, 400-V LSPMSM. To investigate the performance of the motor under the stator inter-turn fault at different loading levels, experimental and simulation results are compared and analyzed for both transient and steady-state responses of the current and speed. The simulation and experimental results are in very good agreement and show that under the stator inter-turn fault, the current magnitude and time response of the phase that contains the inter-turn are highly affected. In addition, due to asymmetry in the stator windings under this fault, the speed experiences some oscillations at steady state. Hence, the developed model can be used to detect the possibility and location of the stator inter-turn fault in an LSPMSM.

Time‐variant PM flux linkages and magnetising inductances of a line‐start PM synchronous motor with composite solid rotor

This study conducts a deep research on a line-start permanent-magnet synchronous motor (LSPMSM) with a composite solid rotor through detailed analyses of two sets of intrinsic motor parameters, i.e. (i) the flux linkages stemming from permanent-magnet (PM) poles, or the so-called PM flux linkages, and (ii) the magnetising inductances related to the stator–rotor magnetic couple. The analyses proceed by separating the motor starting process into a series of sub-states with different slips. At each sub-state, the PM flux linkages and magnetising inductances are both susceptible to the varying saturation of motor cores and hence perform as time-dependent quantities alternating exactly in the slip frequency. Accordingly, these parameters are determined as combinations of cosine functions indicating the quantity alternation, by which the rotor resistances and self-inductances are obtained at the same time. Assembly of all the confirmed motor parameters generates an analytical model of the studied LSPMSM. Responses of this model stay totally in good agreement with those from the finite-element method, and the close result correlation offers an effective validation of the analyses presented in this work.

The Influence of Stator Winding Turns on the Steady-State Performances of Line-Start Permanent Magnet Synchronous Motors

The variation of stator winding turns will directly affect the key parameters of a motor, such as winding resistance and winding reactance, which further affect the steady-state performance of the motor. In order to get excellent steady-state performance from line-start permanent magnet synchronous motors (LSPMSMs) under different load powers, taking an 11 kW LSPMSM as an example, the finite element method (FEM), combined with the steady-state phasor diagram and torque angle characteristic, are used in this paper for the optimal design of the stator winding turns of the prototype. The correctness of the model is verified by comparing the experimental data with the calculated data. First, the influences of different stator winding turns on the no-load, back-induced electromotive force (EMF), as well as on inductance and overload ability are studied, and the variation mechanism is obtained. In addition, from the perspective of the torque angle characteristic, the influence of the change in synchronous inductance caused by the number of turns on the steady-state power angle is studied. Second, the variation of the current and power factors with turn number is obtained by studying the steady-state power angle and end voltage. Based on the coupling relationship between the no-load back EMF and the power angle, the mechanism of non-linear variation of current and power factor is revealed. Finally, the variation of the number of turns on the core loss and eddy current loss is analyzed under various operating conditions, and the variation mechanism is revealed, based on the armature reaction theory.

Effect of high frequency harmonic voltage on the performance of line start permanent magnet synchronous motor

PurposeA large number of high-frequency harmonic voltages exist in the output voltage of the inverter, which will affect the performance of the motor. The purpose of this paper is to obtain the influence of high frequency harmonic voltage on the performance of the line start permanent magnet synchronous motor (LSPMSM) and reveal the mechanism of influence. The research results can provide help for the design of LSPMSM driven by inverter drives.Design/methodology/approachFirst, the actual output voltage data of the inverter is collected, and then the fundamental voltage and high frequency harmonic voltage data can be obtained by performing the fast Fourier transformation method on the voltage data. Second, the finite element model is established. During the finite element calculation, the obtained fundamental voltage and the main harmonic voltage components are used as the voltage source. To research the effect of high frequency harmonic voltage on the performance of motor, a reference group without high frequency harmonic voltage is set up, which is used to compare and analyze the effect of high-frequency harmonics on the performance of the motor. To verify the correctness of the model, a prototype based on the model parameters is manufactured, and then the back EMF experiment and load experiment are performed. The test data and calculation results are compared and analyzed.FindingsThe coupling relationship between high frequency time harmonic magnetic field and low frequency space harmonic magnetic field is obtained. The stator copper loss and rotor eddy-current loss are calculated and analyzed under normal supply voltage and abnormal supply voltage, and the influence mechanism is revealedOriginality/valueThe coupling relationship between high frequency time harmonic magnetic field and low frequency space harmonic magnetic field is obtained. The sensitivity of the high frequency harmonic voltage to the stator copper loss and rotor eddy-current loss is obtained, and the mechanism of losses change is revealed.

Design improvement of dual‐pole LSPM synchronous motor

This article presents a design improvement of the dual-pole, two-speed line start permanent magnet (LSPM) synchronous motor. For this purpose, the operational performance of the motor with dual-pole structure is first compared with the conventional single-pole motor to identify its performance limitations. Next, the structure of the dual-pole rotor is modified accordingly to address the related limitations. The proposed, modified design reduces the number of PMs in the rotor structure and offers a better steady state and transient performance. The motor is analysed using 2D finite element analysis (FEA), and results are verified by experimental tests on the motor prototype.

Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

Neural Network-Based Diagnostic Tool for Detecting Stator Inter-Turn Faults in Line Start Permanent Magnet Synchronous Motors

Three-phase line-start permanent magnet synchronous motors are considered among the most promising types of motors in industrial applications. However, these motors experience several faults, which may cause significant financial losses. This paper proposed a feed-forward neural network-based diagnostic tool for accurate and fast detection of the location and severity of stator inter-turn faults. The input to the neural network is a group of representative statistical and frequency-based features extracted from the steady-state three-phase stator current signals. The current signals with different numbers of shorted turns and loading conditions are captured using the developed finite element JMAG ™ model for interior mount LSPMSM. In addition, an experimental set-up was built to validate the finite element model and the proposed diagnostics tool. The simulation and experimental test results showed an overall accuracy of 93.125% in detecting the location and the size of inter-turn, whereas, the accuracy in detecting the location of the fault is 100%.

Modified grey wolf method for optimization of PM motors

The paper presents an algorithm and computer software for the optimization of electromagnetic devices. The mathematical model of the optimization method was presented. The modification of the classical grey wolf algorithm was developed. The modification consists in decreasing the coefficient responsible for the possibility of migration individuals in the permissible area of solved task. The optimization procedure was elaborated in the Borland Delphi environment. The optimization of the rotor of the line-start permanent magnet synchronous motor has been carried out. It has been pointed out that the grey wolf algorithm is effective method for optimization of electromagnetic devices.

Design of A Novel Line Start Synchronous Motor Rotor

Line start permanent magnet synchronous motors (LS-PMSM) are preferred more and more in industrial applications, because they can start on their own and because of their high efficiency. In this study, a new LS-PMSM rotor typology is suggested, which is modelled using surface mount permanent magnets, in which two different slot types have been used together. The rotor of an asynchronous motor on the industrial market in the IE2 efficiency segment has been remodeled in the study, resulting in an increase in motor efficiency from 85% to 91.8%. A finite elements software was used for determining motor design and performance, in addition to analytical methods.

Influence of Wye-and Delta-Connected Winding on the Performance of Line Start Permanent-Magnet Synchronous Motor

Abstract In order to obtain the influence of wye (Y)-and delta ( \Delta)-connected winding on line start permanent magnet synchronous motor (LSPMSM), taking a 15 kW LSPMSM as an example, the two dimensional (2-D) finite element method (FEM) and analytical method are used to calculate the motor performance. The influence of 3rd harmonic current in \Delta-connected winding on the motor electromagnetic field is analyzed. The difference of the losses and capacity of starting and overload between the Y- and \Delta-connected winding are studied. Finally, combined with the related experiments, the correctness of the calculation model is verified and the reliability of the research results are proved.

Comparative Parameters Investigation of Composite Solid Rotor Applied to Line-Start Permanent-Magnet Synchronous Motors

This paper presents a composite solid rotor applied to improve the starting and synchronization capabilities of the line-start permanent magnet synchronous motor (LSPMSM). The rotor is mainly composed of solid steels to employ their high starting torque. A squirrel cage and some air slots are designed to be added on the rotor surface. During the starting process, the cage carrying eddy currents constitutes a branch in parallel with that of the solid steel, and hence decreases the total rotor impedance. Meanwhile, the surface slots enlarge the eddy current area of the solid steel and further reduce the rotor resistance. All these rotor parameters turning smaller lead to a higher induction torque, and thus enhance the motor performances of starting and synchronization. A set of comparisons about rotor parameters, induction torques, and speed-time responses are implemented among the LSPMSMs with the composite solid rotor and other solid ones lacking cage or slots. Results of the comparisons validate the advantages of the cage slot attachment as well as the motor performance improvement by applying the composite solid rotor.

Parameters determination and dynamic modelling of line‐start permanent‐magnet synchronous motor with a composite solid rotor

A line-start permanent-magnet synchronous motor (LSPMSM) with an author-designed composite solid rotor has been proven to enjoy high capabilities of starting and synchronisation. In this study, the improved LSPMSM is further researched by an investigation on parameters reflecting the motor intrinsic properties, i.e. the rotor impedance, magnetising inductance, and permanent-magnet flux linkage. According to the investigation, it is found that not all these focused parameters constant, but rather exhibit different values under changing slips. A 2D finite-element-method (FEM) covering rotor end effects is applied to obtain the values of the slip-related parameters. The determined parameters pave the path for establishing a dynamic model to predict the steady-state and transient motor performances. The model completes operation in several seconds but yields result nearly identical to those derived from the 3D FEM. The short calculation period and acceptable results accuracy validate the qualification of the presented model.