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This paper introduces a novel dual-air-gap surface permanent magnet synchronous motor (DAG-SPMSM) and investigates its electromagnetic characteristics. The motor comprises two stators (inner and outer) and a single rotor with permanent magnets on both sides (inner and outer). The magnets are arranged in a zig-zag configuration to isolate the inner and outer stator and rotor magnets. Additionally, a magnetic shield is incorporated into the rotor to further isolate the rotor magnetic flux, which results in a localized short flux path that can reduce core loss. The insertion of the magnetic shield also affects the flux path, reducing torque ripple. The electromagnetic characteristics, such as flux path, flux density, and torque, are analyzed using finite element analysis. The effectiveness of using a magnetic screen is also evaluated, and simple experiments are conducted to validate the observed characteristics of the proposed motor. [ABSTRACT FROM AUTHOR]

In this paper, the design of novel slotless permanent magnet synchronous motor (PMSM) for a collaborative robot was studied considering the manufacture process of winding. The winding manufacture process of novel slotless PMSM was proposed in three steps. First, the two types of coil units were manufactured based on the winding jig to assemble the coil units. Second, the coil unit was manufactured using the injection molding based on the plastic material such as polyphenylene sulfide (PPS). Third, the units of the coil were assembled to form a stator winding. Considering this manufacture process of winding, the slotless motor design was studied for the collaborative robot. For the design and analysis of slotless motor, finite element analysis (FEA) was performed through ANSYS Maxwell. The electromagnetic performance was analyzed according to the pole-slot combination. Considering the space of the collaborative robot, the basic model was designed. Based on the basic model, the electromagnetic performance was analyzed according to the design parameters such as the thickness of magnet and yoke and turns per slot. Considering the torque and current density, the final model was designed. To verify the FEA results, the slotless motor was manufactured and the experiment and FEA results were compared. [ABSTRACT FROM AUTHOR]

When a magnetic bearing is used in the design of a high-speed motor, no friction and wear occur because of the principle of magnetic levitation; however, the size of the entire system increases. An integrated magnetic bearing motor is a motor with a magnetic bearing inserted inside the rotor that can minimize the increase in the size of the entire system. In this study, a method to reduce the bearing force ripple and torque ripple of an integrated magnetic bearing motor through parameters for a Halbach array and permanent magnet tapering is proposed. When designing an integrated magnetic bearing motor, because the magnetic bearing is located inside the rotor, the influence of the magnetic flux of the rotor and stator on the magnetic flux of the magnetic bearing should be minimized. By combining the magnetic fluxes of the magnetic bearing, rotor, and stator at the rotor back yoke, magnetic saturation occurs, and the performance of the bearing force and torque ripples decreases. The bearing force and torque according to the Halbach array and permanent magnet tapering were analyzed using finite element analysis. The average bearing force and torque were maximized, and the ripple was minimized through the rotor parameters. Thus, the validity of the main design variables selected to improve the output characteristics was confirmed. [ABSTRACT FROM AUTHOR]

This paper introduces a novel dual-air-gap surface permanent magnet synchronous motor (DAG-SPMSM) and investigates its electromagnetic characteristics. The motor comprises two stators (inner and outer) and a single rotor with permanent magnets on both sides (inner and outer). The magnets are arranged in a zig-zag configuration to isolate the inner and outer stator and rotor magnets. Additionally, a magnetic shield is incorporated into the rotor to further isolate the rotor magnetic flux, which results in a localized short flux path that can reduce core loss. The insertion of the magnetic shield also affects the flux path, reducing torque ripple. The electromagnetic characteristics, such as flux path, flux density, and torque, are analyzed using finite element analysis. The effectiveness of using a magnetic screen is also evaluated, and simple experiments are conducted to validate the observed characteristics of the proposed motor.

In the SPMSM no-speed control system, the traditional SMC speed controlling led to a difference in adjustment speed, a large amount of overshoot and obvious chattering. In order to solve this problem, a new non-singular fast Terminal-SMC speed controller is designed and the continuous function υ(s) is used to replace the traditional symbolic function, which effectively improves the observation accuracy, and reduces the system chattering. The Lyapunov function is designed to prove the system’s stability. The simulation results show that the new NSFT-SMC has faster responded speed, stronger system robustness, and less chattering during stable operation. Comparing with traditional SMC speed control and hyperbolic tangent function SMC speed control, it has better control performance.

In this paper, the design of novel slotless permanent magnet synchronous motor (PMSM) for a collaborative robot was studied considering the manufacture process of winding. The winding manufacture process of novel slotless PMSM was proposed in three steps. First, the two types of coil units were manufactured based on the winding jig to assemble the coil units. Second, the coil unit was manufactured using the injection molding based on the plastic material such as polyphenylene sulfide (PPS). Third, the units of the coil were assembled to form a stator winding. Considering this manufacture process of winding, the slotless motor design was studied for the collaborative robot. For the design and analysis of slotless motor, finite element analysis (FEA) was performed through ANSYS Maxwell. The electromagnetic performance was analyzed according to the pole-slot combination. Considering the space of the collaborative robot, the basic model was designed. Based on the basic model, the electromagnetic performance was analyzed according to the design parameters such as the thickness of magnet and yoke and turns per slot. Considering the torque and current density, the final model was designed. To verify the FEA results, the slotless motor was manufactured and the experiment and FEA results were compared.

It is a difficult to accurately estimate the rotor position in a surface permanent magnet synchronous motor (SPMSM), especially for low speed conditions because the back electromotive force (EMF) is almost zero. In this paper, an improved sliding mode observer (SMO) with a continuous sliding mode switching function (which could reduce the chattering effect) is proposed to estimate the real-time rotor position at a low speed. Through the introduction of an intermediate variable H, the back EMF is extended at low speed, which could improve the estimation accuracy for the rotor position. In addition, the chattering phenomenon is reduced by redesigning the sliding switching function. On the other hand, inverter nonlinearity also results in torque ripple and deteriorates the drive performance because of the harmonic components in the three-phase stator current. Here, a generalized sliding discrete Fourier transform (GSDFT) strategy is studied to extract the harmonic components, which can then be compensated with the corresponding compensation voltage calculated from the motor mathematical model. With the proposed strategy, the estimation accuracy can be apparently restricted when the rotor speed is lower than 50 rpm, while the chattering effect is also improved. With the nonlinearity compensation, the total harmonic distortion obviously decreases, which can improve the rotor estimation and the torque performance. In addition, the GSDFT algorithm executes in approximately half the time of the SDFT compensation method.

In this paper, a new maximum torque per ampere (MTPA) control method for surface permanent magnet synchronous motors (SPMSMs) controlled by the scalar control (v/f) method is proposed. The scalar control is a sensorless method that controls only the magnitude and the frequency of the stator voltage vector without the information of the rotor position. This method suggests the injection of the high frequency voltage signal in the stator current vector reference frame, which can be calculated from the measured phase currents, to avoid the use of rotor position information. In addition, this method adjusts only the magnitude of the stator voltage to minimize the stator current based on the calculated input power. Another merit of this method is the robustness of the MTPA control to machine parameter errors or variations. With this proposed method, the stator current can be minimized in the whole speed-torque range and the drive efficiency can be improved. Simulation and experimental results are provided to verify the performance of this control strategy.

When a magnetic bearing is used in the design of a high-speed motor, no friction and wear occur because of the principle of magnetic levitation; however, the size of the entire system increases. An integrated magnetic bearing motor is a motor with a magnetic bearing inserted inside the rotor that can minimize the increase in the size of the entire system. In this study, a method to reduce the bearing force ripple and torque ripple of an integrated magnetic bearing motor through parameters for a Halbach array and permanent magnet tapering is proposed. When designing an integrated magnetic bearing motor, because the magnetic bearing is located inside the rotor, the influence of the magnetic flux of the rotor and stator on the magnetic flux of the magnetic bearing should be minimized. By combining the magnetic fluxes of the magnetic bearing, rotor, and stator at the rotor back yoke, magnetic saturation occurs, and the performance of the bearing force and torque ripples decreases. The bearing force and torque according to the Halbach array and permanent magnet tapering were analyzed using finite element analysis. The average bearing force and torque were maximized, and the ripple was minimized through the rotor parameters. Thus, the validity of the main design variables selected to improve the output characteristics was confirmed.

In the SPMSM no-speed control system, the traditional SMC speed controlling led to a difference in adjustment speed, a large amount of overshoot and obvious chattering. In order to solve this problem, a new non-singular fast Terminal-SMC speed controller is designed and the continuous function υ(s) is used to replace the traditional symbolic function, which effectively improves the observation accuracy, and reduces the system chattering. The Lyapunov function is designed to prove the system's stability. The simulation results show that the new NSFT-SMC has faster responded speed, stronger system robustness, and less chattering during stable operation. Comparing with traditional SMC speed control and hyperbolic tangent function SMC speed control, it has better control performance. [ABSTRACT FROM AUTHOR]

The surface permanent magnet synchronous motor (SPMSM) speed regulation system is easily affected by the inner parameter perturbation and the external load disturbance at run time. To solve this problem, the H∞ robust control strategy is proposed in this paper. First, given the systematic uncertainties, the H∞ robust current controller based on the Hamilton-Jacobi Inequality is designed to ensure the robustness of current control under the SPMSM nominal mathematical model. This model is expressed as the port-controlled Hamiltonian with the dissipation form; second, the linear matrix inequality-based H∞ sliding surface and the sliding control law are designed under the extended state space expression of the SPMSM motion equation. Thereby, the robust H∞ sliding mode speed controller is acquired, thus realizing the robustness of speed control and improving the dynamic characteristics of the system. Finally, the effectiveness and availability of the proposed control strategy are verified by the hardware-in-the-loop simulation experiment.

The detection of the electrical fault in speed controller under a Motor Control Unit System (MCUS) has been amply viewed in the research paper. Nevertheless, the research work in this domain have been constantly followed on sensor-based vector control of synchronous motor. This paper combines the Power Inverter Voltage (PIV) faults detection (signal-based approach) with sliding mode technique (model-based) to provide Fault Tolerant Control (FTC) for sensorless speed Permanent Magnet Synchronous (PMS) motor drive. Back-EMF sliding mode observer (Back-EMF-SMO) is used for rotor position and stator currents estimation and simultaneously MCUS fault diagnosis. The fault diagnosis for MCUS faults of PMS motor drives using a Hilbert Transform. The motor phase currents signals shapes for various modes of MCUS faults are examined. A PIV Faults Detection and Isolation (FDI) algorithm is used to allow the switchover to a redundant leg. The obtained findings exhibit the effectiveness of the suggested FDI process particularly to detect and to isolate a PIV faults for sensorless PMS motor drives. [ABSTRACT FROM AUTHOR]

In this article, a sensorless field-oriented vector control strategy combined with an improved adaptive sliding mode observer and a back electromotive force (back EMF) observer is presented for a surface permanent magnet synchronous motor. First, based on a sliding mode, a current adaptive observer with estimation of back EMF is proposed to obtain the error of the back EMF, which can reduce system chattering. Then, a back EMF observer based on the back EMF error is constructed to adaptively track the rotor speed and position, which avoids complicated computation. Moreover, the stability of two observers is proved by using the Lyapunov stability theory. Finally, some simulations and experiments are given to show that the proposed method can track the changes of rotor speed and position with good characters, such as fast convergence, little chattering, and good robustness. [ABSTRACT FROM AUTHOR]

Model predictive current control (MPCC) can predict future motor behavior according to a motor model. In practice, however, motor parameters will vary at run time, and the parameter mismatch disturbances caused by the variation in motor parameters will deteriorate the MPCC performance. To suppress the parameter mismatch disturbances effectively, this paper proposes a modified MPCC with a current variation update mechanism. In contrast with the traditional current prediction equation that contains crude model parameters, the modified current prediction equation contains only measured information, taking advantage of the proposed current variation update mechanism, which can update the modified prediction equation within each sampling period. A simulation established by MATLAB software indicates that the proposed method can effectively suppress the parameter mismatch disturbances. Experiments are carried out to verify the correctness of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, the fuzzy neural controller has been used to control the speed of the surface permanent magnet synchronous motor, despite its uncertainty in parameters and torque load. This method first uses a variety of local controllers (such as PIDs, LQRs, etc.) for different engine operating points and for different uncertainties and torque for precise engine control. Then the adaptive fuzzy controller learns that all of the local controllers are included and therefore, despite the indeterminacy in the parameters and torque of the motor, the reference speed with fast response and the least stable mode error are followed. Fuzzy neural network training algorithm is a mixed method, which is a combination of two methods of least squares and descending gradients with error propagation method. The least squares method is used to adjust the linear parameters of the output layer and the descending gradient algorithm uses an error propagation method for adjusting and updating the nonlinear parameters of the fuzzy layer. In the end, simulation of this controller is compared with H∞, Fuzzy and PID controller. Simulation results show the effectiveness of the proposed method in the paper. [ABSTRACT FROM AUTHOR]

The offset voltage variation of current sensors is mainly due to the thermal drift, and it causes torque ripples in current vector-controlled surface permanent magnet synchronous motor (SPMSM) drives. This paper proposes a current offset error compensator for the current vector-controlled SPMSM drives used in robotic applications, wherein dynamic movements frequently occur. The current offset error compensator for this kind of applications should provide a stable performance in estimating current offset errors during dynamic movements. Especially, the current offset error compensator should be able to suppress interferences from outer-loop controllers. In this paper, analysis on a synchronous frame current regulator is performed to see the relation between current commands and measured currents under the current offset error existing condition. The analysis shows that pure current offset error components can be obtained by subtracting low-pass filtered current commands from measured currents in a synchronous reference frame. It means that the interference from current commands in correcting current offset errors can be easily decoupled by the simple subtraction process, and the dynamic control capability of a current offset error compensator could be significantly improved. The dynamic performance of the proposed current offset error compensator is proved through simulations and experiments. [ABSTRACT FROM AUTHOR]

A novel initial position detecting strategy of sensorless control for the surface-mounted permanent magnet synchronous motor is proposed, the scheme combines the virtual high frequency (HF) voltage pulsating injection method with the carrier frequency component method. In order to improve the sensorless control performance, this method adds the virtual HF rotation frame based on the traditional HF pulsating injection method. At the same time, the carrier frequency component signals are utilized to detect a magnetic pole. The simulation and experimental results show that the proposed method does not require proportion-integration (PI) regulation. The novel magnetic pole judgment method can effectively improve the detecting performance of sensorless control in the long algorithm execution time, complex process, etc. The experimental results verified the correctness of the strategy. [ABSTRACT FROM AUTHOR]

This paper deals with clamping force simulation and experimental result of the Electro Mechanical Brake (EMB) for the High-Speed-Train (HST). Three phase Surface Permanent Magnet Synchronous Motor (SPMSM) is applied to the clamping force control of EMB. At the initial development stage, Proportional Integral (PI) current control under synchronous d-q axis frame was applied to the SPMSM torque control. In addition, an anti-windup controller, which is advantageous for fast current tracking, is proposed to improve the torque output. Matlab/Simulink simulation results were compared with the experimental results measured by the clamping force sensors of the EMB test rig. The experimental results were verified compared to the brake design specification of the High-Speed Electric Multiple Unit-430 Experimental (HEMU-430X) train.

A novel nonlinear model for surface permanent magnet synchronous motors (SPMSMs) is adopted to estimate the initial rotor position for hybrid electric vehicles (HEVs). Usually, the accuracy of initial rotor position estimation for SPMSMs relies on magnetic saturation. To verify the saturation effect, the transient finite element analysis (FEA) model is presented first. Hybrid injection of a static voltage vector (SVV) superimposed with a high-frequency rotating voltage is proposed. The magnetic polarity is roughly identified with the aid of the saturation evaluation function, based on which an estimation of the position is performed. During this procedure, a special demodulation is suggested to extract signals of iron core saturation and rotor position. A Simulink/MATLAB platform for SPMSMs at standstill is constituted, and the effectiveness of the proposed strategy is verified. The proposed method is also validated by experimental results of an SPMSM drive. [ABSTRACT FROM AUTHOR]

In-wheel motors bring a fundamental change in electric vehicle technology by removing conventional mechanical components and freeing up space inside the vehicle body. This approach ultimately helps to realize all-wheel independent control for improved vehicle dynamics and increased vehicle design freedom. However, when space allowed for an in-wheel motor is taken into consideration, high torque density, high efficiency, and wide-speed-range capability are typically required. This paper specifically investigates a 20-pole–24-slot surface permanent magnet synchronous motor with consequent pole rotor for in-wheel direct drive since this topology is well suited for high-pole motors and thus high-torque direct-drive applications. Extensive finite-element analysis is carried out to characterize the proposed motor, and the practical feasibility of the proposed motor is discussed. Finally, the validity of the analysis was experimentally verified. [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]

This paper deals with clamping force simulation and experimental result of the Electro Mechanical Brake (EMB) for the High-Speed-Train (HST). Three phase Surface Permanent Magnet Synchronous Motor (SPMSM) is applied to the clamping force control of EMB. At the initial development stage, Proportional Integral (PI) current control under synchronous d-q axis frame was applied to the SPMSM torque control. In addition, an anti-windup controller, which is advantageous for fast current tracking, is proposed to improve the torque output. Matlab/Simulink simulation results were compared with the experimental results measured by the clamping force sensors of the EMB test rig. The experimental results were verified compared to the brake design specification of the High-Speed Electric Multiple Unit-430 Experimental (HEMU-430X) train. [ABSTRACT FROM AUTHOR]