Permanent Magnet Linear Motor Research Articles

Simulation and Experiments on Optimization of Vortex-Induced Vibration Power Generation System Based on Side-by-Side Double Blunt Bodies

In order to improve the utilization efficiency of converting low-flow current energy into electric energy for Reynolds number 10,000 ≤ Re ≤ 40,000, this paper proposes a vortex-induced vibration power generation system based on a side-by-side double blunt body. In this system, the side-by-side double blunt body structure is used in the current energy capture part to enhance the collection of low-flow current energy; the permanent magnet linear motor is used in the electric energy conversion part to improve the efficiency of electric energy conversion; and a laboratory device is constructed for testing. The effects of the blunt body structure parameters and the center spacing ratio on the energy harvesting performance of the system are qualitatively explained by constructing a simulation model. Compared with the single blunt body energy capture structure, the side-by-side double blunt body structure increases the vibration amplitude by 1.04 times and the lift by 1.14 times at the center spacing S/D = 2.4. Meanwhile, energy harvesting can be realized at a lower flow velocity, increasing the vortex-induced vibration’s energy capture range. Finally, the power generation system was experimentally verified in the laboratory, and the results showed that the vibration amplitude of the double blunt body structure was increased by 1.12 times compared to the single blunt body. The maximum output power of the generator is 10.55 W when the water velocity is 0.7 m/s. The energy conversion efficiency of the power generation system can reach a maximum of 52.93%, which is 12.33% higher than that of a single blunt body structure, which proves that the system has a higher power conversion efficiency than that of a conventional single conversion system.

Interior Profile Accuracy Assessment Method of Deep-Hole Parts Based on Servo Drive System.

Dimensional and profile measurements of deep-hole parts are key processes both in manufacturing and product lifecycle management. Due to the particularity of the space conditions of deep-hole parts, the existing measurement instruments and methods exhibit some limitations. Based on the multi-axis, highly precise servo drive system, a novel measuring device is developed. The laser displacement sensors are fed by the flux-switching permanent magnet linear motor, and the part is rotated by the servo motor. On this basis, the assessment methods of roundness, straightness, and cylindricity are proposed by employing the least square method (LSM). Additionally, considering the axial center deviation between the sensors and the part, the rotating center coordinate is optimized by the gradient descent algorithm (GDM). Then, the measurement system is constructed and the experiment study is conducted. The results indicate favorable evaluation error of the LSM fitting and GDM iteration. Compared with the coordinate measuring machine (CMM), the measured results show good consistency. In the error analysis, the angle positioning error of measured point is less than 0.01°, and the axial positioning error is less than 0.05 mm. The proposed system and assessment method are regarded as a feasible and promising solution for deep-hole part measurements.

Modelling and optimization of TPMLMs with slotted stators based on Bayesian DNN

AbstractThe Permanent Magnet Linear Motor (TPMLM) is widely used in different industrial fields. TPMLMs with slots and iron cores have high power density, but their thrust fluctuations and copper losses are significant. Due to the nonlinearity and saturation of magnetic circuits, their electromagnetic models are complex and the accuracy of numerical methods is very inferior. Substantially accurate modelling is crucial for motor optimisation design. In this paper, a data‐driven modelling method based on Bayesian optimisation deep neural network (DNN) is proposed to improve the accuracy of the electromagnetic field. The finite element (FE) modelling under different structural parameters is analysed and provides a training dataset for DNN. Then, a multi‐objective optimisation problem for the slotted TPMLM is carried out based on the multi‐objective black hole algorithm. Compared to the original design, the average thrust of TPMLM increased by 49.37%, the thrust fluctuation percentage decreased by 9.59%, and the coil copper consumption percentage decreased by 2.64%. The results show that the improved DNN model has very high modelling accuracy, providing a new way for motor design and optimisation.

Hybrid Analytical Model of Permanent Magnet Linear Motor Considering Iron Saturation and End Effect

Hybrid Analytical Model of Permanent Magnet Linear Motor Considering Iron Saturation and End Effect

Double-Sided Single-Set Winding Coordinated Active Levitation Control of Linear Permanent Magnet Motor Considering Mover Air-Gap Offset

Double-Sided Single-Set Winding Coordinated Active Levitation Control of Linear Permanent Magnet Motor Considering Mover Air-Gap Offset

Analytical modelling of the linear transverse flux permanent magnet motor using magnetic equivalent circuit method

AbstractThe authors propose an analytical modelling approach for the linear transverse flux permanent magnet motor using the magnetic equivalent circuit method. The main focus of this study is to predict the phase flux‐linkage characteristic of the motor. Essential equations required for implementation of the model and how to solve it are described clearly so that someone can use it easily. A typical motor is selected to apply the proposed model and simulation results, including static characteristics of flux‐linkage and thrust, are presented. To validate the developed analytical model, the discussed motor is also analysed with 3D finite element method using MAXWELL software and the obtained simulation results are compared to each other.

Bound‐based control design for permanent magnet linear motor servo system with inequality constraints and uncertainties

AbstractThe permanent magnet linear motor (PMLM) systems are widely applied in various engineering fields. However, the state inequality constraints and uncertainties of parameters and unknown external disturbances need to be further explored. In this article, first, a state transformation method is proposed for converting bounded states to unbounded states. As a result, the output state of system is limited within the expected boundary constraint. Then, a new control strategy is constructed. This strategy can ensure that the controlled system with uncertainties is uniformly bounded and uniformly ultimately bounded. Finally, the effectiveness of the controller and the state transformation method are verified through simulation of PMLM system. The inequality constraints of the output state are satisfied, and the system performance is improved.

Adaptive neural sliding mode control of an uncertain permanent magnet linear motor system with unknown input backlash in laser processing

In this article, a novel robust and high-precision control scheme is developed for a permanent magnet linear motor system in large-range laser processing subject to unknown system uncertainties and input backlash. First, to enhance the robustness of the controller, an adaptive neural sliding mode control (SMC) scheme is proposed. Besides, to address the system uncertainties, a novel simplified radial basis neural network (RBFNN) is applied in the adaptive SMC scheme. Subsequently, considering that the unexpected chattering introduced by SMC strategy, another RBFNN is employed to approximate the optimal switching gain. In addition, considering that the nonlinear input backlash caused by actuator can also cause the fluctuation of the input signal, an inverse backlash model with the method of reverse compensation is proposed to further minimize the effect of the input backlash on control accuracy. Finally, simulation results, validation experiments, and laser processing experiments are provided to demonstrate that the proposed control scheme significantly reduces the impact of chattering and input backlash. Additionally, it exhibits outstanding control accuracy.

Design and analysis of ELM-based predefined time sliding mode adaptive controller for PMLM position control under physical constraints

Achieving accurate position tracking for robotics and industrial servo systems is an extremely challenging task, particularly when dealing with control saturation, parameter perturbation, and external disturbance. To address these challenges, a predefined time convergent sliding mode adaptive controller (PTCSMAC) has been proposed for a permanent magnet linear motor (PMLM). A novel sliding mode surface (SMS) with predefined time convergence PDTC has been constructed, which ensures that the error converges to zero within the prescribed time. The system not only meets the expected performance standards but also has a uniformly bounded motor speed. The trajectory tracking error in SMS is proven to converge to zero within the predefined time. This predefined time stability of the closed-loop system has been demonstrated by using the Lyapunov stability criterion with PDTC. The convergence time (CT) can be arbitrarily set, and the upper bound of it is not affected by the initial value and control parameters of the system. A new updated version of extreme learning machine (ELM) is introduced to approximate the uncertain part of the system based on PDTC. The ELM is also provided with the hyperbolic tangent function to estimate the saturation constraint. This is done by converting the function into a linear function concerning the unconstrained control input variable. Then, based on established stability, a novel sliding mode adaptive controller (PTCSMAC) with predefined time convergence is designed. The convergence time (CT) of the controller is unaffected by the initial conditions as well as the control parameters. The rigorous numerical simulations on the PMLM model with complex disturbances verify the strong robustness and high-precision tracking characteristic of the proposed control law.

Data-Driven Indirect Iterative Learning Control.

In this work, a data-driven indirect iterative learning control (DD-iILC) is presented for a repetitive nonlinear system by taking a proportional-integral-derivative (PID) feedback control in the inner loop. A linear parametric iterative tuning algorithm for the set-point is developed from an ideal nonlinear learning function that exists in theory by utilizing an iterative dynamic linearization (IDL) technique. Then, an adaptive iterative updating strategy of the parameter in the linear parametric set-point iterative tuning law is presented by optimizing an objective function for the controlled system. Since the system considered is nonlinear and nonaffine with no available model information, the IDL technique is also used along with a strategy similar to the parameter adaptive iterative learning law. Finally, the entire DD-iILC scheme is completed by incorporating the local PID controller. The convergence is proved by applying contraction mapping and mathematical induction. The theoretical results are verified by simulations on a numerical example and a permanent magnet linear motor example.

A General Control Method for Half-Centralized Open Winding Permanent-Magnet Motor Drive System

In this paper, a general control method based on duty ratio selection for half-centralized open winding primary permanent-magnet linear motor (HCOW-PPMLM) drive system is proposed. The proposed control method is designed from the perspective of single-phase subsystem. The novelty of this paper is the voltage process and modulation, which can realize the expansion from two movers to multi movers. The design of voltage process and modulation contains voltage preprocessor, saturation limiter and duty ratio distributor. In the voltage preprocessor, phase voltages are transferred to phase modulation index. The saturation limiter deals with excessive phase modulation indexes based on the independent over-modulation principle. The duty ratio distributor distributes the voltage demand into inverters by the common-leg-based distribution principle. Compared to existing method, the proposed control method can realize the expansion from two movers to multi movers and has less computation burden. In addition, more mover quantities will not increase the complexity of analysis and design. Finally, the effectiveness of the proposed control method has been verified by experimental results.

Simplified Phase Model Predictive Voltage Control for Half-Centralized Open-End Winding Permanent-Magnet Motor Systems

In order to obtain a wider speed range for the permanent-magnet linear motor drive system, a half-centralized open-end winding (OEW) topology is studied. In this topology, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> movers are supplied by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> +1 voltage-source-inverters (VSIs), and all these VSIs share a common dc bus voltage. In order to reduce the computation burden, a simplified phase model predictive voltage control (S-PMPVC) is proposed in this paper. For S-PMPVC, the optimal and suboptimal base levels are defined. When the optimal base level cannot be implemented, the suboptimal base level is selected. As a result, S-PMPVC requires smaller computation burden while the performances are not degraded. By taking the advantage of the smaller computation burden, S-PMPVC can adopt higher control frequency to improve performances. The effectiveness of S-PMPVC has been verified by simulation and experimental results.

Robust control and experimental validation of trajectory tracking for permanent magnet linear motors based on constraint-following under uncertainty

AbstractThis paper proposes a robust control approach to achieve high-precision trajectory tracking for permanent magnet linear motor (PMLM) system containing uncertainties by describing the dynamic model of PMLM based on the Udwadia-Kalaba equation combined with constraint-following method. First, the system of PMLM is described as a constraint-following system by adding the generalized constraint force to the unconstrained Udwadia-Kalaba equation of PMLM system. Second, the robust constraint-following controller is designed based on the proposed model after uncertainty analysis. Moreover, the proposed controller is verified to guarantee deterministic performance for uncertain systems: uniformly bounded and uniformly ultimately bounded. Third, the numerical simulation and experimental validation demonstrate the effectiveness of proposed controller. Finally, the design approach of constraint-following can be applied to other systems with uncertainties.

Design and Optimization of a Novel Permanent Magnet Linear Motor with the Same Number of Poles and Slots

Design and Optimization of a Novel Permanent Magnet Linear Motor with the Same Number of Poles and Slots

Comparative Analysis of Normal Force Characteristics and Dynamic Influence of Linear Flux-Switching Permanent Magnet Motor for Rail Transit

Comparative Analysis of Normal Force Characteristics and Dynamic Influence of Linear Flux-Switching Permanent Magnet Motor for Rail Transit

Design and utilization of thrust fluctuation of slotted-tubular permanent magnet linear motor: Mechatronics for low-frequency vibration forming machine

Usually, the conventional low-frequency vibration forming machine has a main transmission mechanism as the driving source to provide forming force and an auxiliary mechanism as the vibration source to generate vibration force. The transmission chain is long and the structure is complex and bloated, which affects the forming process and product quality. This paper presents a novel mechatronics idea of low-frequency vibration forming machine, which uses a slotted tubular permanent magnet synchronous linear motor (slotted-TPMLM) as both the driving source and the vibration source. The key is that the slotted-TPMLM provides sufficient forming force accompanied with a certain low-frequency vibration force. Consequently, this paper focuses on the thrust fluctuation caused by the structure. Firstly, the effect of end force and the influence of cogging force are discussed in detail through Fourier analyses, especially the stator adjustment length and pole-slot combination. Then, the slotted-TPMLM is designed, manufactured, and tested. The results show that the slotted-TPMLM can provide a certain low-frequency vibration force (low frequency of 4.8 Hz at 100 mm/s and 48 Hz at 1000 mm/s), which meets the technical requirements. Consequently, the feasibility of the novel mechatronics idea of a low-frequency vibration forming machine has been verified. This research will contribute to the field of linear motors and metal forming machines.

A Novel Detent Force Reduction Method Based on Primary Modular Twice Offset for Alternating Pole Permanent Magnet Linear Motor

A Novel Detent Force Reduction Method Based on Primary Modular Twice Offset for Alternating Pole Permanent Magnet Linear Motor

Electromagnetic Vibration Analysis of Transverse Flux Permanent Magnet Linear Submersible Motor for Oil Production

A transverse flux linear motor is a special type of linear motor with a high thrust force density, and it has broad application prospects in the field of linear direct-drive systems. In the process of oil production, the vibration of the linear motor poses a significant amount of harm to the system due to its special slender structure. This paper focuses on the electromagnetic vibration of a transverse flux permanent magnet linear submersible motor (TFPMLSM). Firstly, the no-load air gap flux density is calculated based on the field modulation principle. Secondly, the radial electromagnetic force (REF) of the TFPMLSM is calculated, and the finite element method (FEM) is used to analyze the time-space and spectral characteristics of the REF. Then, the influence of secondary eccentricity on the frequency spectrum of the REF is further concluded. Finally, the natural frequencies of each vibration mode are calculated using the modal superposition method and the influence of the REF on the motor vibration is obtained through magnetic-structural coupling analysis. The research results found that the motor does not cause resonance at low speeds, and the fundamental frequency of REF has the greatest impact on electromagnetic vibration.

A novel robust bounded control with inequality constraints and experimental validation for permanent magnet linear motor

In order to solve the problem that the trajectory of a permanent magnet linear motor may be out of bounds in practice and eliminate the influence of uncertainty on trajectory tracking, we propose a robust bounded control based on inequality constraints. First, the dynamics model of the permanent magnet linear motor is established, and then, the constrained output state variables are converted into unconstrained state variables by state conversion. Secondly, based on the dynamics model after state transformation, a novel control method containing both nominal and robust terms is proposed. Finally, the stability of the PMLM system is proved by the Lyapunov minimax method. Simulations and experiments with different algorithms are carried out on the PMLM system and the CSPACE platform. Based on the analysis of the experimental results, it can be found that robust bounded control based on inequality constraints can significantly improve the dynamic performance of the PMLM system and achieve high accuracy.

A Novel Fault Tolerance Structure of Arc Linear Flux Switching Permanent Magnet Motors Based on Redundant Winding

This paper presents a novel structure of the arc linear flux switching permanent magnet motor based on the redundant winding to inhibit the rises of the motor losses and temperature due to the open circuit fault tolerance. Firstly, the structural characteristic of the arc linear flux switching permanent magnet motor is introduced. Then, the fault tolerance current of single phase open circuit fault is calculated for different winding connection forms. The fault tolerance performances under different conditions are compared from a special view of motor temperature rises. Finally, a novel structure for fault tolerance enhancement is proposed, which can effectively improve the freedom degree of the fault tolerance current by using the redundant winding. This novel structure takes full advantage of the circumferential air gap between the arc stator. The calculation results show that the novel structure can allow the fault tolerance of open circuit fault has little influence on the motor copper losses and temperature rises while maintaining the on-load torque.