High-speed Permanent Magnet Synchronous Motor Research Articles

Design and testing of CFRP sleeve for a high-speed permanent magnet synchronous motor with surface-mounted rotor

A high-speed (HS) permanent magnet (PM) synchronous motor (HSPMSM) with a carbon fiber-reinforced plastic (CFRP) protective sleeve in the surface-mounted rotor was explored in this study. In view of retaining the PMs at HS operations, the high-strength CFRP sleeve was designed on the basis of a process that could be summarized as follows. First, a multi-physics analysis of the rotor was conducted. The requirements to the CFRP sleeve were obtained from electromagnetic analysis, loss analysis, heat flow coupling computational fluid dynamics analysis, structural analysis, and rotor dynamics analysis. Second, the CFRP sleeve was designed by theoretical analysis. From the results, the thickness values of the carbon fibers in the circumferential and helical directions were chosen to be 4 and 1 mm, respectively, while the helical angle of carbon fibers was chosen to be 70°. Then, a plate-shaped CFRP product and a cylindrical CFRP product were fabricated to verify the strength and stiffness of the CFRP sleeve. The performance test results show that the hoop strength and elastic modulus and the axial strength and elastic modulus of the plate-shaped CFRP products at 20 °C are 1963 MPa @ 156 GPa and 550 MPa @ 36 GPa, respectively. The hoop strain and axial strain of the cylindrical CFRP product under 35 MPa are about 3000 and 1900 μe, which meet the design requirements of the HSPMSM.

Observers for High-Speed Sensorless PMSM Drives: Design Methods, Tuning Challenges and Future Trends

Rotor position and speed estimation methods are consolidated to reduce the cost and volume of permanent magnet synchronous motor (PMSM) sensorless control drives while maintaining high performance. Advanced nonlinear algorithms require accurate design for precise estimation tracking throughout the entire PMSM operation range. This paper presents a broad review of the main high-speed estimation methods for sensorless PMSM drives. First, the stability constraints and design methodologies of the main estimation techniques presented in the literature are discussed. In the second part, it is investigated the new observer design trends, which are used under non-ideal conditions, such as robustness to distortions, the effects of parameter variation, sensorless parameter estimation, and low sampling-frequency-to-speed ratio operation. Future trends on the design of observers for high-speed sensorless PMSM drives are also discussed.

Comparative electromagnetic design of high-speed PMSM with reduced torque ripple for automotive application, part 1 – stator design

This paper concerns the initial motor sizing of a high-speed permanent magnet synchronous motor (HSPMSM), that will be used in educational and research applications. Starting dimensions are chosen from an existing machine topology. In the first part, the motor optimization is performed w.r.t. optimal magnetic loading of the stator, for a fixed rotor topology. The rotor optimization is not included, because further thermal and especially mechanical simulations must be conducted.

Compensation Method of Position Estimation Error for High-Speed Surface-Mounted PMSM Drives Based on Robust Inductance Estimation

This article proposes a compensation method of position estimation error for high-speed surface-mounted permanent magnet synchronous motors based on robust inductance estimation. The proposed method relies on the variation of the estimated $\delta$ -axis back back-electromotive force when a small current is injected into the $\gamma$ axis. The inductance estimation error is limited within ${\bf \pm \!5\%}$ when the nominal resistance and inductance vary $\bf \pm 30\%$ of their real values. With the estimated inductance, the position estimation error can be well compensated. Compared with the conventional current-injection method, the proposed method has enhanced robustness against the system noises. Benefiting from this, it is effective to estimate the inductance with a small injected current ( $ \bf 0.5\%$ of the rated current), where the conventional methods fail. Finally, the effectiveness of the proposed method is validated by simulation and experiment results on a 100 kr/min (1.67 kHz) high-speed permanent magnet synchronous machines accurately with 10-kHz sampling frequency.

Optimal Adaptive Super-Twisting Sliding-Mode Control Using Online Actor-Critic Neural Networks for Permanent-Magnet Synchronous Motor Drives

In this paper, a novel optimal adaptive-gains super-twisting sliding-mode control (OAGSTSMC) using actor-critic approach is proposed for a high-speed permanent-magnet synchronous motor (PMSM) drive system. First, the super-twisting sliding-mode controller (STSMC) is adopted for reducing the chattering phenomenon and stabilizing the PMSM drive system. However, the control performance may be destroyed due external disturbances and parameter variations of the drive system. In addition, the conservative selection of the STSMC gains may affect the control performance. Therefore, for enhancing the standard super-twisting approach performance via avoiding the constraints on knowing the disturbances as well as uncertainties upper bounds, and to achieve the drive system robustness, the direct heuristic dynamic programming (HDP) is utilized for optimal tuning of STSMC gains. Consequently, an online actor-critic algorithm with HDP is designed for facilitating the online solution of the Hamilton-Jacobi-Bellman (HJB) equation via a critic neural network while pursuing an optimal control via an actor neural network at the same time. Furthermore, based on Lyapunov approach, the stability of the closed-loop control system is assured. A real-time implementation is performed for verifying the proposed OAGSTSMC efficacy. The experimental results endorse that the proposed OAGSTSMC control approach achieves the PMSM superior dynamic performance regardless of unknown uncertainties as well as exterior disturbances.

Design of High-Speed Multilayer IPMSM Using Ferrite PM for EV Traction Considering Mechanical and Electrical Characteristics

This article proposes a design method of the high-speed multilayer interior permanent magnet synchronous motor (HSML IPMSM) employing the ferrite permanent magnet (PM). Since the maximum speed of the traction motor in this article is 15 kr/min, the mechanical stability must be considered. Additionally, in the case of the HSML IPMSM, as the number of the PM layers increases, the thickness of the PMs must be reduced to be mechanically stable. On the other hand, because the ferrite PM has a relatively low coercive force compared with the Nd PM, an irreversible demagnetization of the ferrite PM of the HSML IPMSM is likely to occur. Therefore, the mechanical stability and irreversible demagnetization must be considered at all design steps. As the irreversible demagnetization and mechanical stability can be confirmed only by the finite-element analysis (FEA), the proposed method in this article is a design method that considers the irreversible demagnetization and mechanical characteristics at all design steps using the FEA. After the design of the traction motor is completed using this design method, the designed motor is manufactured. To verify the validity of the design method, experiments are conducted on the manufactured motor, and the test results are compared with FEA results.

Luenberger Position Observer Based on Deadbeat-Current Predictive Control for Sensorless PMSM

Two problems can cause control performance degradation on permanent magnet synchronous motor (PMSM) systems, namely, fluctuation of PMSM parameters and the time delay between current sampling and command value update. In order to reduce the influence of these problems, a new current-predictive control strategy is proposed in this article for medium- and high-speed PMSM. This strategy is based on the discrete mathematical model of PMSM. This new control strategy consists of two main steps: First, an integrator is applied to calculate current compensation value; second, the predictive current value is obtained through deadbeat-current predictive method. The stability of predictive control system is also proved in the article. With this deadbeat-current predictive control scheme, the real current can reach the desired value within one control-step. Based on this new current control method, Luenberger observer and phase-locked loop position tracker is applied in this article. Experimental results for 0.4 kW surface-mounted PMSM confirm the validity and excellent performance for parameters fluctuation of new current predictive control.

High-Speed Permanent Magnet Synchronous Motor Iron Loss Calculation Method Considering Multiphysics Factors

For the high-speed permanent magnet synchronous motors (HSPMSMs), their magnetic fields are more complicated with the rotating magnetization and harmonics considered. Furthermore, there are interaction effects on motor iron loss from high frequency, temperature, and compressive stress. In order to obtain the accurate HSPMSM iron loss calculation model, different iron loss models are proposed, in this article, considering these physical factors, and the iron loss model considering the interaction effect of the multiphysics factors is given. The magnetic field, temperature field, and stress field are analyzed for HSPMSM by finite-element method (FEM). Then, the proposed models are employed to calculate the iron loss of the silicon steel sheet and the prototype. The accuracy of the proposed iron loss model, which can consider the interaction effect of the multiphysics factors, is verified by the experimental test measurements on the prototype.

Chaos Suppression for Coupled Electromechanical Torsional Vibrations in a High-Speed Permanent Magnet Synchronous Motor Driven System via Multitime Delayed Feedback Control

In this paper, we describe a coupled nonlinear electromechanical torsional vibration model of a high-speed permanent magnet synchronous motor driven system based on the Lagrange–Maxwell theory. The chaotic state is induced by external excitation forces. A multitime delay feedback control scheme is derived to suppress chaos in such vibrations. An analytical criterion condition for chaos is deduced by Melnikov’s method. Detailed numerical studies, including bifurcation diagram, phase portrait, and a Poincaré map, confirm the analytical prediction. It is revealed that the chaotic motion can be effectively suppressed by reducing or increasing the feedback parameters of the multitime delay feedback control scheme.

Computation-Efficient Position Estimation Algorithm for Permanent Magnet Synchronous Motor Drives Under Distorted Conditions

This article proposes a computationally efficient position-sensorless control scheme for medium- and high-speed permanent magnet synchronous motor (PMSM) drives under distorted conditions. An adaptive comb observer (ACO) is designed for accurate position estimation by eliminating primary distortions simultaneously, including dc offsets from current measurement, odd harmonics caused by inverter nonlinearity, and even harmonics due to the modulation. A frequency-locked loop based on the Lyapunov stability theory is embedded in the ACO to ensure the observer’s stability and fast convergence of the estimated variables. Compared with conventional adaptive position observers that usually require high-order filtering networks, the proposed scheme only consists of four delay operators and does not require complicated discretization. Therefore, it can simplify digital implementation and reduce the computational burden of the sensorless algorithm. To validate the effectiveness of the proposed observer, comparative experiment tests of the proposed ACO and conventional methods are performed on a 15-kW PMSM setup.

Estimation of Rotor Temperature of Permanent Magnet Synchronous Motor Based on Model Reference Fuzzy Adaptive Control

For high-speed permanent magnet synchronous motor (PMSM), its efficiency is significantly affected by the performance of permanent magnets (PMs), and the phenomenon of demagnetization will occur with the increase of PM temperature. So, the temperature detection of PMs in rotor is very necessary for the safe operation of PMSM, and direct detection is difficult due to the rotation of rotor. Based on the relationship between permanent magnet flux linkage and its temperature, in this paper, a new temperature estimation method using model reference fuzzy adaptive control (MRFAC) is proposed to estimate PM temperature. In this method, the model reference adaptive system (MRAS) is built to estimate the permanent magnet flux linkage, and the fuzzy control method is introduced into MRAS, which is used to improve the accuracy and applicable speed range of parameters estimated by MRAS. Different permanent magnet flux linkages are estimated in MRFAC based on the variation of stator resistance, which corresponds to different working temperatures measured by thermal resistance, and the PM temperature will be obtained according to the estimated permanent magnet flux linkage. At last, the back electromotive force (BEMF) is measured on the experimental motor, and the flux linkage and PM temperature of the experimental motor are deduced according to the BEMF. Compared with the experimental results, the estimated PM temperature is very close to the actual test value, and the error is less than 5%, which verifies that the proposed method is suitable for the estimation of PM temperature.

High-Precision Rotor Position Correction Strategy for High-Speed Permanent Magnet Synchronous Motor Based on Resolver

A high-precision rotor position correction strategy for a 2.5 kW@10 000 r/min permanent magnet synchronous motor (PMSM) based on the resolver is proposed in this article. The resolver as the rotor position sensor for PMSM has the advantage of long service life and high anti-interference. However, it is common that the unbalance amplitude of the resolver signal and the nonideal resolver-to-digital converter cause the rotor position estimation error. To solve these problems, a self-adaption rotor position correction strategy is proposed. First, the relationship between the q-axis current and the rotor position estimation error is analyzed. The error from estimate and the imbalances of the resolver-to-digital converter circuit are decoupled. Then, a rotor position correction strategy based on self-adaption controller is presented, and the self-adaption controller can compensate the estimation error both from unbalance amplitude of the resolver signal and the nonideal resolver-to-digital converter. Finally, the effectiveness and feasibility of the correction strategy are verified by the experiments on a 2.5 kW@10 000 r/min PMSM platform.

Magnetic Field Characteristics and Stator Core Losses of High-Speed Permanent Magnet Synchronous Motors

This study focuses on the core losses in the stator region of high-speed permanent magnet synchronous motors, magnetic field characteristics in the load region, and variations in iron losses caused by changes in these areas. A two-pole 120 kW high-speed permanent magnet synchronous motor is used as the object of study, and a two-dimensional transient electromagnetic field-variable load circuit combined calculation model is established. Based on electromagnetic field theory, the electromagnetic field of the high-speed permanent magnet synchronous motor under multi-load conditions is calculated using the time-stepping finite element method. The magnetic field distribution of the high-speed permanent magnet synchronous motor under a multi-load condition is obtained, and the variations in iron core losses in different parts of the motor under multi-load conditions are further analyzed. The calculation results show that most of the stator iron core losses are dissipated in the stator yoke. The stator yoke iron loss under the no-load condition exceeds 70% of the total stator iron core loss. The stator yoke iron loss under rated operation conditions exceeds 50% of the total stator iron core loss. The stator loss under rated load operation conditions is higher than that under no-load operation. These observations are sufficient to demonstrate that the running status of high-speed motors is closely related to the stator iron losses, which have significance in determining the reasonable yoke structure of high-speed and high-power motors and the cooling methods of motor stators.

Electromagnetic torque and strength analysis of combination rotor in high speed PMSM

For a high-speed permanent magnet synchronous motor supported by air foil bearings, analyzing the influence of the electromagnetic torque on the strength of the combination rotor was necessary. In this study, the electromagnetic torque was obtained using the analytical calculation and the finite element simulation. The contact interface stress analytical equation affected by the electromagnetic torque was elaborated. A three-dimensional finite element model simulating the combination rotor was constructed, and the stress calculations were performed. The strength of the combination rotor met the design requirement. It properly reflected the characteristics of the electromechanical analysis in the combination rotor. The operation experiments were realized to verify the electromagnetic performance and the strength of the combination rotor. The simulation and experimental results were significant for the electromechanical design and analysis of the combination rotor.

Multiphysics modeling and design of high-speed permanent magnet synchronous motors

This paper presents a multiphysics modeling and design methodology for high speed permanent magnet synchronous motors (PMSM) for electric traction applications. In this proposed methodology, the electromagnetic, thermal and mechanical fields are coupled together. The electromagnetic model is used to analyze the electromagnetic performances and losses of the PMSM, which then feed the thermal and mechanical models. The thermal model focuses on the machine’s temperature rise while the mechanical model is used to analyze the stress distribution of the PMSM. Combined together, a powerful multiphysics model aimed for the design of high speed PMSMs is achieved. The design results prove that the designed PMSM can simultaneously meet the requirements of high power density, high temperature and high reliability.

Analysis of Temperature Rise in High-Speed Permanent Magnet Synchronous Traction Motors by Coupling the Equivalent Thermal Circuit Method and Computational Fluid Dynamics

Analysis of Temperature Rise in High-Speed Permanent Magnet Synchronous Traction Motors by Coupling the Equivalent Thermal Circuit Method and Computational Fluid Dynamics

Correction of Rotor Position Estimation Error for High-Speed Permanent Magnet Synchronous Motor Sensorless Drive System Based on Minimum-Current-Tracking Method

This article focuses on the issue of the rotor position estimation error correction for high-speed permanent magnet synchronous motor sensorless drive system. First, a rotor position estimator is designed. Then the estimation error caused by different kinds of nonideal factors is analyzed in detail. Estimation error results in larger amplitude of the stator current, the larger loss, and the degradation of the output torque. To eliminate the estimation error, a novel correction method based on the “minimu-current-tracking (MCT)” method is proposed in this article. The main idea of the proposed method is to obtain the minimum amplitude of the stator current adaptively through the MCT algorithm. The estimation error can be reduced to zero by correcting the compensation factor of the designed position estimator and observing the amplitude of stator current until the amplitude converges to the minimum value. The proposed method has two advantages: 1) the estimation error caused by no matter which kind of nonideal factor can be completely corrected; 2) no sensitive parameters are required in the proposed method. Finally, sufficient simulated results and experimental results verify the effectiveness of the proposed MCT-based method.

Nonregenerative Braking of Permanent Magnet Synchronous Motor

This article proposes nonregenerative braking algorithm for the permanent magnet synchronous motor (PMSM), suitable for low-cost drive equipped with the front-end diode rectifier. The algorithm is based on the selection of braking trajectories with maximum iron and copper losses, while keeping dc-bus voltage at the acceptable level and with operational limits satisfied. The braking scheme is not calculation intensive and is not prone to PMSM parameter variations; thus, it is suitable for inexpensive microcontroller and PMSM, both native for low-cost drives. The algorithm is tested and validated under a variety of operating conditions, using a typical high-speed PMSM used in home appliances.

Investigation of electromechanical coupling lateral/torsional vibration in a high-speed rotating continuous flexible shaft of PMSM

The rotor of Permanent Magnet Synchronous Motors (PMSM) is an electromechanical coupled dynamics system. The asymmetrical magnetic field-induced mechanical vibration has important effect on the operation performance of the high speed and high power density PMSM. In this paper, an electromechanical coupled lateral/torsional dynamic model caused by electromagnetic excitation is derived based on a Lagrange–Maxwell approach. The stability of the equilibrium was analyzed using a linearized matrix of the system equation. A stability criteria of coupled torsional-lateral motions was provided, and the influences of the electromagnetic and mechanical parameters on mechanical vibration stability were investigated. Finally, the vibration damping of the electromechanical coupling parameters vibration was explored. These results we represent get us better to understand the nonlinear response of the eccentric PMSM rotor system and are beneficial to control and diagnose the eccentric.

Multi-Objective Optimal Design of High-Speed Surface-Mounted Permanent Magnet Synchronous Motor for Magnetically Levitated Flywheel Energy Storage System

This paper presents a multi-objective optimized design for a 75 kW, 24 000 r/min high-speed surface-mounted permanent magnet synchronous motor (SMPSM) for a magnetically levitated flywheel energy storage system. The main goal of the optimization process is to determine the optimal motor geometry, and thus obtain maximum efficiency, minimum weight, and minimum torque ripple in the SMPSM. To achieve this goal, three objective functions are used. The first function is used to obtain maximal output torque, and thus produce highest efficiency; the second function is used to minimize materials utilization to realize the lowest possible production cost; and the third function is used to achieve minimal torque ripple, and thus constrain the motor’s vibration and noise. The optimization process uses an ant colony algorithm with continuous domains. The optimized motor parameters can be selected from the Pareto solution set obtained. A comparison of the results calculated using the optimization algorithm with the results obtained using finite-element analysis software shows a good agreement.