Magnetic field and performance analysis of a tubular permanent magnet linear synchronous motor applied in elevator door system

A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.

Comparative Analysis of Bilateral Permanent Magnet Linear Synchronous Motors With Different Structures

Permanent magnet linear synchronous motor(PMLSM)has the advantages of high thrust density and good control accuracy,which can be applied in high-power and high-speed occasions.In this paper,the analytical models are established to obtain the electromagnetic performance for the PMLSMs with dual secondaries and dual primaries.The air-gap flux density and the electromagnetic thrust are also obtained by the finite element model to verify theoretical analysis.Besides,an improved structure is also put forward in order to suppress the thrust fluctuation of the PMLSM.Finally,the advantages and disadvantages of two PMLSMs topologies are listed.These analyses would provide a guide for the design of PMLSMs applied in high-power and high-speed occasions.

Optimal design of auxiliary-teeth to solve circulation current reduction of permanent magnet linear synchronous motor

A discontinuity of magnetic circuits according to the end effect is generated in the permanent magnet linear synchronous motor （PMLSM）. Due to the unbalanced back electro-motive force （EMF） and impedance produced, unbalanced current is generated. The cireulatin8 current, which is caused by a decrease in the thrust, is generated by the unbalanced current. The optimal design of auxiliary-teeth at the end of the mover was carried out to solve the unbalance of phase by using design of experiment （DOE）, and compared with the basic model through finite element analysis （FEA）. As a result, the auxiliary-teeth model compensates for the decrease of thrust caused by the unbalanced phase. Also, this model is proven to reduce the detent force by the vibration and noise of the PMLSM and copper loss caused by the circulating current.

Study on three dimensional electromagnetic model for permanent magnet linear synchronous motor

In this paper, with the non-salient pole permanent magnet linear synchronous motor (PMLSM)being cited, by using Fourier transform method and "slot-by-slot", "pole -by-pole" current approach, a 3D electromagnetic field model of PMLSM is established. Special attention is paid to its structure and the influence of longitudinal and transverse end effect. The distribution of electromagnetic field of PMLSM can be obtained directly and promptly by using FFT algorithm. It can also be used for the analysis of other LSM.

Characteristics of permanent magnet linear synchronous motor fed by spwm inverter based on field-circuit coupled method

Presented field-circuit coupled adaptive time-stepping finite element method to study on permanent magnet linear synchronous motor (PMLSM) characteristics fed by SPWM voltage source inverter.In air-gap field where the direction or magnitude of the field is changing rapidly,the smallest elements are demanded due to high accuracy to use adaptive meshing technique.The co-simulation was used with the status space functions and time-step finite element functions,in which time-step of the status space functions was the smallest than finite element functions'.The magnitude relation of the normal elec- tromagnetic force and tangential electromagnetic force and the period were attained,and current curve was very abrupt at current zero area due to the bigger resistance and leak- age reactance,including main characteristics of motor voltage and velocity.The simulation results compare triumphantly with the experiments results.

A Permanent Magnet Linear Synchronous Motor Drive for HTS Maglev Transportation Systems

A permanent magnet linear synchronous motor （PMLSM） for a high temperature superconducting （HTS） maglev system has been studied, including the motor structure, control strategy, and analysis techniques. Finite element analysis （FEA） of magnetic field is conducted to accurately calculate major motor parameters. Equivalent electrical circuit is used to predict the drive＇s steady-state characteristics, and a phase variable model is applied to predict the dynamic performance. Preliminary experiment with a prototype has been made to verify the theoretical analysis and the HTS-PM synchronous driving technology.

Design strategy for detent force reduction of permanent magnet linear synchronous motor

The detent force of a permanent magnet linear synchronous motor （PMLSM） is analyzed and the corresponding optimization methods are presented to reduce it. The detent force, which is divided into two components, i.e. resulting from the end effect and resulting from the slotting effect, can be analyzed respectively by the finite element method （FEM）. To reduce the detent force arising from the end effect, several optimal design techniques are utilized, namely, adopting the suitable length and end shape of the primary armature. The detent force resulting from the slotting effect is reduced by means of skewing and adjusting the width of the magnets mounted on the secondary armature, and adopting the fractional slots of the primary armature. The validity of the analytical detent force predictions and the effectiveness of the detent force reduction techniques are verified by the experimental measurements.

Calculation of optimal current density of double side permanent magnet linear synchronous motor

The use of design method considering a coil temperature to maximize the thrust density of a double side coreless permanent magnet linear synchronous motor(PMLSM) was presented.The optimal current density where the coil temperature reaches an allowable temperature with heat analysis was applied to a magnetic circuit design.Changing optimal current density is verified whenever the design parameters of the motor are altered.The design parameters of the motor were applied to thrust calculation.In this way,the optimal model,which is a reversal of the existing design method,is deduced.The results were compared with the experimental data to verify their validity.When the convection heat transfer coefficient is applied to other models,the results of the analysis and test values show good concordance.The method proposed has some limitations.

Temperature Rise Calculation and Velocity Planning of Permanent Magnet Linear Synchronous Motor under Trapezoidal Speed

For permanent magnet linear synchronous motor(PMLSM) working at trapezoidal speed for long time, high thrust brings high temperature rise, while low thrust limits dynamic performance. Thus, it is crucial to find a balance between temperature rise and dynamic performance. In this paper, a velocity planning model of the PMLSM at trapezoidal speed based on electromagnetic-fluid-thermal(EFT) field is proposed to obtain the optimal dynamic performance under temperature limitation. In this model, the winding loss is calculated considering the acceleration and deceleration time. The loss model is indirectly verified by the temperature rise experiment of an annular winding sample. The actual working conditions of the PMLSM are simulated by dynamic grid technology to research the influence of acceleration and deceleration on fluid flow in the air gap, and the variation rule of the thermal boundary condition is analyzed. Combined with the above conditions, the temperature rise of a coreless PMLSM(CPMLSM) under the rated working condition is calculated and analyzed in detail. Through this method and several iterations, the optimal dynamic performance under the temperature limitation is achieved. The result is verified by a comparison between simulation and prototype tests, which can help improve the dynamic performance.

Integrated Sliding Mode Velocity Control of Linear Permanent Magnet Synchronous Motor with Thrust Ripple Compensation

In this paper,a compound sliding mode velocity control scheme with a new exponential reaching law(NERL)with thrust ripple observation strategy is proposed to obtain a high performance velocity loop of the linear permanent magnet synchronous motor(LPMSM)control system.A sliding mode velocity controller based on NERL is firstly discussed to restrain chattering of the conventional exponential reaching law(CERL).Furthermore,the unavoidable thrust ripple caused by the special structure of linear motor will bring about velocity fluctuation and reduced control performance.Thus,a thrust ripple compensation strategy on the basis of extend Kalman filter(EKF)theory is proposed.The estimated thrust ripple will be introduced into the sliding mode velocity controller to optimize the control accuracy and robustness.The effectiveness of the proposal is validated with experimental results.

Prediction of the Inductance in a Synchronous Linear Permanent Magnet Generator

This paper presents calculations of the varying inductances profile for a synchronous linear surface mounted permanent magnet generator in an ABC reference system. Calculations are performed by utilizing the reluctance term, known from analytic calculations and finite element method simulations. With the inductance term identified, the voltage difference between the generator’s no load and load voltage can be calculated and an external circuit can be designed for optimal use of the generator. Two different operation intervals of the linear generator are considered and the results are discussed. The result indicates that time costly finite element simulations can be replaced with simple analytical calculations for a surface mounted permanent magnet linear generator.

SIMULATION RESEARCH ON CHARACTERISTICS OFPERMANENT MAGNET LINEAR SYNCHRONOUS MOTOR

In this paper, a simulation model of Permanent Magnet Linear Synchronous Motor (PMLSM) is established by using phase equations method. Special attention is paid to its structure and the influence of longitudinal end effect and the unbalance of current. The analytic method can be used for the analysis of dynamic and static characteristics of PMLSM.

Impulsive control for permanent magnet synchronous motors with uncertainties:LMI approach

A permanent magnet synchronous motor （PMSM） may have chaotic behaviours under certain working conditions, especially for uncertain values of parameters, which threatens the security and stability of motor-driven operation. Hence, it is important to study methods of controlling or suppressing chaos in PMSMs. In this paper, the stability of a PMSM with parameter uncertainties is investigated. After uncertain matrices which represent the variable system parameters are formulated through matrix analysis, a novel asymptotical stability criterion is established by employing the method of Lyapunov functions and linear matrix inequality technology. An example is also given to illustrate the effectiveness of our results.

Robust fuzzy sliding-mode control for T-S model based permanent magnet synchronous motor

A fuzzy sliding-mode control (FSMC) scheme based on T-S fuzzy models was proposed for the permanent magnet synchronous motor (PMSM) drive system to solve the speed tracking problem. A T-S fuzzy model was firstly formed to represent the nonlinear system of PMSM. For converting the tracking control into a stabilization problem, a new control design was proposed to define the internal desired states. Then, the FSMC controller for PMSM system with parameter variation and load disturbance was designed based on the fuzzy model. The performance of the proposed controller was verified by experimental results on PMSM system. The results show that the FSMC scheme can drive the dynamics of PMSM into a designated sliding surface in finite time and guarantee the property of asymptotical stability. The information of upper bound of modeling errors as well as perturbations is not required when using the FSMC controller.

Current Loop Disturbance Suppression for Dual Three Phase Permanent Magnet Synchronous Generators Based on Modified Linear Active Disturbance Rejection Control

A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d and q axis currents in the d-q subspace and harmonic currents in the x-y subspace.In the d-q subspace,the proposed strategy uses a model-based LADRC to enhance the decoupling effect between the d and q axes and the disturbance rejection ability against parameter variation.In the x-y subspace,the 5th and 7th harmonic current suppression abilities are improved by using quasi-resonant units parallel to the extended state observer of the traditional LADRC.The proposed modified LADRC strategy improved both the steady-state performance and dynamic response of the DTP-PMSG system.The experimental results demonstrate that the proposed strategy is both feasible and effective.

Coordinated Robust PID-based Damping Control of Permanent Magnet Synchronous Generators for Low-frequency Oscillations Considering Power System Operational Uncertainties

In recent years, with the growth of wind energy resources,the capability of wind farms to damp low-frequency oscillations(LFOs) has provided a notable advantage for the stabilityenhancement of the modern power grid. Meanwhile, owingto variations in the power system operating point (OP), thedamping characteristics of LFOs may be affected adversely. Inthis respect, this paper presents a coordinated robust proportional-integral-derivative (PID) based damping control approachfor permanent magnet synchronous generators (PMSGs)to effectively stabilize LFOs, while considering power system operationaluncertainties in the form of a polytopic model constructedby linearizing the power system under a given set ofOPs. The proposed approach works by modulating the DC-linkvoltage control loop of the grid-side converter (GSC) via a supplementaryPID controller, which is synthesized by transformingthe design problem into H-infinity static output feedback(SOF) control methodology. The solution of H-infinity SOF controlproblem involves satisfying linear matrix inequality (LMI)constraints based on the parameter-dependent Lyapunov functionto ensure asymptotic stability such that the minimal H-infinityperformance objective is simultaneously accomplished forthe entire polytope. The coordinated damping controllers forthe multiple wind farms are then designed sequentially by usingthe proposed approach. Eigenvalue analysis confirms the improveddamping characteristics of the closed-loop system forseveral representative OPs. Afterward, the simulation results, includingthe performance comparison with existing approaches,validate the higher robustness of the proposed approach for awide range of operating scenarios.

基于比例谐振内模扩张状态观测器的PMLSM推力波动抑制策略

定位力是永磁同步直线电机(PMLSM)产生推力波动的主要原因,导致振动和噪声,恶化驱动系统运行性能。针对这一问题,该文提出一种基于比例谐振内模扩张状态观测器(PR-IMESO)的PMLSM推力波动抑制策略以提高系统控制精度和运行性能。首先,对PMLSM推力波动进行建模与分析,针对推力波动中占比较大的定位力分量,根据内模原理研究考虑定位力模型的内模扩张状态观测器(IMESO),并在观测器中引入谐振项以加强对二次脉动定位力的抑制。所提出抑制策略对PMLSM定位力具有良好的观测及补偿能力,还可对其余未建模的复杂动子推力波动进行抑制,具有较好的推力波动整体抑制效果。最后,在一台750 W的PMLSM实验平台上验证所提出抑制策略的有效性。

基于扰动观测器和改进自适应二阶快速终端滑模的PMLSM伺服系统控制

针对永磁直线同步电动机(PMLSM)在运行时易受到摩擦力、负载扰动及环境变化等不确定影响,设计一种基于扰动观测器和自适应二阶快速终端滑模控制方法。首先,该方法在高阶滑模的基础上结合了快速终端滑模控制,有效加快了系统响应速度。其次,在二阶滑模面的基础上引入条件积分项,该项仅作用于边界层内部,能够有效避免滑模到达阶段由于积分饱和现象导致的超调量过大及响应时间过慢的问题。此外,设计自适应切换控制律,使切换增益在合理的区间内,并根据系统状态进行实时更新,从而削弱抖振现象。最后,为进一步提升系统的鲁棒性,采用扰动观测器对PMLSM系统的集总不确定性进行补偿。经实验验证,该控制方法具有良好的位置跟踪精度和强鲁棒性,且对系统抖振现象有明显削弱作用。

基于FPGA的PMLSM三矢量模型预测电流控制IP核设计及硬件在环验证

为了提升永磁直线同步电机(PMLSM)电流控制的稳态性能和执行速度,同时降低资源消耗,基于现场可编程门阵列(FPGA)设计了一个三矢量模型预测电流控制(TV-MPCC)知识产权(IP)核,并利用FPGA在环可视化验证方法,建立了一个PMLSM的TV-MPCC IP核验证系统。通过Simulink对TV-MPCC策略进行算法级仿真,并优化了基本电压矢量的作用顺序;采用并行与资源共享硬件优化技术设计并封装了一个TV-MPCC IP核,并对其进行了功能仿真;将设计部署在FPGA芯片XC7Z020CLG400-2上,利用FPGA在环可视化验证平台进行实验研究。结果表明,TV-MPCC策略下d、q轴电流跟踪误差和电流脉动均降低90%以上;FPGA工作在100 MHz下,实现一次算法的时间为0.62μs,仅为软件PyCharm执行时间的0.414%。

基于改进分数阶滑模控制的PMLSM直接推力控制

针对分数阶滑模控制在永磁直线同步电机(Permanent Magnet Linear Synchronous Motor, PMLSM)直接推力控制下转速环精度不高、磁链和推力波动大等问题,提出一种改进的分数阶滑模控制算法,即分数阶双幂次指数趋近律、分数阶变速趋近律相结合的组合趋近律,能有效减弱滑模控制引起的系统振荡,加快趋近速率。仿真结果表明:与分数阶滑模控制相比,在PMLSM直接推力控制系统中采取改进分数阶滑模控制,磁链和推力波动明显减弱,系统响应速度加快,提高了PMLSM推力响应的抗干扰能力。