Visualization and Quantitative Evaluation of Eddy Current Loss in Bar-Wound Type Permanent Magnet Synchronous Motor for Mild-Hybrid Vehicles

This paper describes the conductor eddy current loss that occurs in a permanent magnet type synchronous motor with a distributed winding stator using a rectangular copper wire designed for mild hybrid system applications for small vehicles.Compared with the conventional round wire inserter method,the space factor can be improved and the coil-end length can be shortened by applying a so-called hairpin windings using a pre-formed into hairpin shape of bar conductor,and as a result,DC current resistance of the armature winding can be reduced.However,since the conductor cross-sectional area tends to increases,the conductor eddy current loss generated by the space harmonics linkage becomes too large to ignore.In order to study the reduction of the conductor eddy current loss,it is important to visualize the spatial leakage flux distribution which causes loss and finely analyze how the magnetic path is formed.Therefore,analysis of the conductor eddy current loss distribution generated in the bar-wound conductor is performed using the CAE model that faithfully reproduces the coil-end shape of the actual machine.Furthermore,it was qualitatively clarified what ratio of conductor eddy current loss at various driving points.Finally,the results of preliminary study on reduction of conductor eddy current loss are reported.

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.

Sensorless Control of Permanent Magnet Synchronous Motor Based on New Sliding Mode Observer with Single Resistor Current Reconstruction

To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.

Research on Open-circuit Fault Tolerant Control of Six-phase Permanent Magnet Synchronous Machine Based on Fifth Harmonic Current Injection

This paper proposes a novel control approach for fault-tolerant control of dual three-phase permanent magnet synchronous motor(PMSM) under one-phase open-circuit fault.A modified six-phase static coordinate transformation matrix and an extended rotating coordinate transformation matrix are investigated considering the influence of the fifth harmonic space on fault-tolerant control. These mathematical models are further analyzed in the fundamental space and the fifth harmonic space after the fault and to eliminate the coupling between the d-q axis voltage equation in the fundamental wave space and the d-q axis voltage equation in the fifth harmonic space, a secondary rotation coordinate transformation matrix is proposed. To achieve the purpose of reducing torque ripple, the fault-tolerant control method proposed in this paper not only takes the minimum copper loss as the constraint condition, but also injects the fifth harmonic current. The experimental result of current and torque is used to verify the accuracy of fault-tolerant control.

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.

Zero-Sequence Current Suppression Strategy for Open-End Winding Permanent Magnet Synchronous Motor Based on Model Predictive Control

Compared with the traditional three-phase star connection winding,the open-end winding permanent magnet synchronous motor(OW-PMSM)system with a common direct current(DC)bus has a zero-sequence circuit,which makes the common-mode voltage and the back electromotive force(EMF)harmonic generated by the inverters produce the zero-sequence current in the zero-sequence circuit,and the zero-sequence current has great influence on the operation efficiency and stability of the motor control system.A zero-sequence current suppression strategy is presented based on model predictive current control for OW-PMSM.Through the mathematical model of OW-PMSM to establish the predictive model and the zero-sequence circuit model,the common-mode voltage under different voltage vector combinations is fully considered during vector selection and action time calculation.Then zero-sequence loop constraints are established,so as to suppress the zero-sequence current.In the end,the control strategy proposed in this paper is verified by simulation experiments.

Analysis for Rotor Losses of High Speed Permanent Magnet Synchronous Motor

This paper presents an analysis based on analytical method for solid rotor motors for determining the rotor eddy current losses due to the current harmonics of the stator winding. The accuracy of the analytical results is verified by experiments.

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.

Model-free Control of Permanent Magnet Synchronous Linear Motor Based on Ultra-local Model

A model-free control (MFC) method is proposed to improve the dynamic response performance of permanent magnet synchronous linear motors (PMSLMs) and reduce motor parameter changes during motor operation. The MFC is established based on an ultra-local model that uses only the input and output of the system without using any PMSLM parameters. Compared with the conventional proportional-integral (PI) control method, the robustness of the MFC system is superior and can counteract the effects of changing motor parameters and external disturbances. Simulations and experiments are conducted with steady-state operation, sudden addition and subtraction of loads, and motor parameter perturbations. The results confirm that the proposed method is useful and robust to uncertainties in motor parameters and helps improve the dynamic performance of the PMSLM.

Simplified Model Predictive Current Control for Dual Three-phase PMSM with Low Computation Burden and Switching Frequency

Finite-control-set model predictive control(FCSMPC)has advantages of multi-objective optimization and easy implementation.To reduce the computational burden and switching frequency,this article proposed a simplified MPC for dual three-phase permanent magnet synchronous motor(DTPPMSM).The novelty of this method is the decomposition of prediction function and the switching optimization algorithm.Based on the decomposition of prediction function,the current increment vector is obtained,which is employed to select the optimal voltage vector and calculate the duty cycle.Then,the computation burden can be reduced and the current tracking performance can be maintained.Additionally,the switching optimization algorithm was proposed to optimize the voltage vector action sequence,which results in lower switching frequency.Hence,this control strategy can not only reduce the computation burden and switching frequency,but also maintain the steady-state and dynamic performance.The simulation and experimental results are presented to verify the feasibility of the proposed strategy.

基于ESM-REKF的直线电机无差拍预测电流控制

永磁同步直线电机(PMSLM)无差拍预测电流控制(DPCC)在实际系统中受采样延时和电机参数失配的影响,电流跟踪精度下降,从而引起推力波动,为此提出一种基于扩张状态建模(ESM)和抗差扩展卡尔曼滤波(REKF)的无差拍预测电流控制策略。首先,对PMSLM电气子系统的扰动进行分析,借鉴扩张状态观测器的思想,将扰动作为一个高阶积分器以构建ESM;其次,结合ESM设计包含参数变化扰动估计的EKF,在此基础上,为了抑制粗差对状态估计的影响,设计抗差误差协方差阵,从而得到ESM-REKF的扰动估计方法;最后,利用电流预测值和扰动估计值对DPCC进行改进与补偿。仿真和实验结果表明,相对传统DPCC,所提控制策略在标称值下,电流谐波畸变率降低了约5.38%;在电感参数失配下,电流谐波畸变率降低了约9.38%,电磁推力的超调下降了约7%,明显削减采样延时和参数失配对电流预测精度的影响,实现对电流快速准确地跟踪,有效抑制推力波动。

基于负载观测器的PMSM预测电流控制

针对永磁同步电机(permanent magnet synchronous motor,PMSM)预测电流控制系统在线优化计算负担大和抗负载扰动性能不足的问题,提出了一种基于负载转矩观测器的PMSM预测电流控制策略。首先,基于离散空间矢量调制构建虚拟电压矢量,并利用无差拍的思想对备选电压矢量控制集进行优化,降低电压矢量寻优的计算负担。然后,为了提高系统的抗负载扰动能力,设计降阶观测器对负载转矩进行实时观测,并将负载转矩观测值按比例前馈至电流环,补偿由负载转矩变化引起的电流波动。仿真结果表明,所提电压矢量寻优策略在保证控制效果的同时有效降低了计算负担,降阶观测器的引入明显提高了系统的抗负载扰动能力。

双频永磁电机驱动器的共模环流抑制方法

永磁同步电机正往高速化、高压化的方向发展,这会导致电机电流的开关纹波增大、电机损耗增加。然而,考虑到大功率电机驱动器的开关损耗,无法通过直接提高开关频率的方式降低开关纹波。双频永磁电机驱动器可以有效解决大功率和高开关频率之间的矛盾。为了抑制双频逆变器内部的共模环流,降低高频逆变器的容量需求,对共模环流产生的原因进行详细的分析,并提出一种共模环流抑制方法,通过在高频逆变器的输出电压中注入零轴分量,有效降低共模环流,从而减小功率器件的容量和损耗。通过仿真和实验,详细地验证所提方法的有效性。

基于矢量分类的NPC型三电平双三相PMSM的改进模型预测电压控制

多电平多相电机驱动系统存在电压矢量数目多、冗余复杂及多目标非线性约束等问题。以二极管钳位型三电平六相逆变器驱动双三相永磁同步电机为研究对象,以电机谐波电流抑制和逆变器直流侧中点电位平衡控制为目标,提出一种基于电压矢量三角区域分类的改进模型预测电压控制策略。首先,以基波子平面大投影幅值为原则,对729个电压矢量进行初筛;接着,基于三角区域分类方法对筛选后的电压矢量进行分类,并对期望电压进行所属三角区域定位、确定候选矢量。设计满足电机定子电流谐波抑制及逆变器中点电位平衡控制的目标函数;根据电机数学模型和逆变器特征研究多目标控制权重因子的理论设计方法。不同工况下的有效性及对比实验表明,所研究的控制策略不仅能改善多电平多相电机驱动系统的多目标控制性能,还能有效降低控制器计算负担。

Backstepping Control of Speed Sensorless Permanent Magnet Synchronous Motor Based on Slide Model Observer

This paper presents a backstepping control method for speed sensorless permanent magnet synchronous motor based on slide model observer. First, a comprehensive dynamical model of the permanent magnet synchronous motor(PMSM) in d-q frame and its space-state equation are established. The slide model control method is used to estimate the electromotive force of PMSM under static frame, while the position of rotor and its actual speed are estimated by using phase loop lock(PLL) method. Next,using Lyapunov stability theorem, the asymptotical stability condition of the slide model observer is presented. Furthermore, based on the backstepping control theory, the PMSM rotor speed and current tracking backstepping controllers are designed, because such controllers display excellent speed tracking and anti-disturbance performance. Finally, Matlab simulation results show that the slide model observer can not only estimate the rotor position and speed of the PMSM accurately, but also ensure the asymptotical stability of the system and effective adjustment of rotor speed and current.

基于滑模谐波控制的PMSM转矩脉动抑制

针对永磁同步电动机工作时由于谐波电流产生的谐波电磁转矩脉动问题,提出了一种基于滑模控制的谐波控制器,以实现在全频域范围内降低PMSM转矩谐波的目的。通过滑模速度谐波控制器提取电动机转速谐波,得到q轴谐波电流期望值,避免了传统谐波输入法中对电动机的提前测定。通过滑模电流谐波控制器得到逆变器输入电压。针对谐波信号变化频率快的特点,设计了一种新型的趋近律函数,同时引入模糊神经网络控制器对趋近律参数进行在线修正,有效提升了滑模控制器的动态品质。仿真结果表明,该方法避免了复杂的数学运算,在不同工况下有效抑制了PMSM谐波电磁转矩脉动。

永磁同步电机自整定分数阶PID速度控制

为优化永磁同步电机(PMSM)控制效果,提高电机整体控制性能及鲁棒性,提出自整定分数阶PID控制策略,并应用于永磁同步电机速度环控制。该控制器较常规PID多了2个可调参数,能够更加灵活地控制受控对象。设计了前馈解耦的电流控制器、模糊分数阶PID控制器,利用模糊规则在线整定控制器参数;在Matlab中搭建永磁同步电机仿真模型,对比本文控制策略与常规PID控制、普通分数阶PID控制及滑模控制,分析不同速度下PMSM变负载系统转速仿真曲线。仿真结果表明,模糊分数阶PID控制器抗干扰性强、跟踪精度高、响应速度快,具有更好的控制效果。

开绕组永磁同步电机的无模型电流预测控制策略

针对共母线型开绕组永磁同步电机的零序电流和模型电流预测控制中电机参数易受影响的问题,提出了一种无模型电流预测策略。首先,将电流预测控制与无模型控制结合,引入线性状态观测器对系统扰动进行估计;其次,使用价值函数以及电压矢量扇形策略选择最佳基本电压矢量和作用时间,且通过非零矢量产生的零序电压和参考值的差量得到补偿的零序电压,并选择计算其注入的混合零矢量以及作用时间;最后,用滑模控制改进状态误差反馈的自抗扰控制来代替速度环的PI控制。仿真结果表明,该改进方法使零序电流的波动范围缩小在0.2 A之间,提高了系统的响应速度,验证了此方法的有效性和可行性。

Robust Position Anti-Interference Control for PMSM Servo System With Uncertain Disturbance

Aiming to suppress the influence of uncertain disturbances in the drive control of permanent magnet synchronous machines(PMSM),such as the parameter uncertainties and load disturbance,a robust anti-interference control for the angular position tracking control of a PMSM servo system has been proposed in this paper.During the position tracking,uncertain system disturbances being regarded as a lumped unknown term will be online observed by a nonlinear disturbance observer(NDOB),of which the influence will consequently be counteracted by a robust backstepping compensator(RBC).The asymptotical stability of proposed control scheme is analyzed and designed according to the Lyapunov stability criterion,and its convergence against the system uncertain disturbance is verified on a prototype PMSM servo platform and shows good performance in rotor angular position tracking and anti-interference.

Model Predictive Current Control with Adaptive-adjusting Timescales for PMSMs

A model predictive current control(MPCC)with adaptive-adjusting method of timescales for permanent magnet synchronous motors(PMSMs)is proposed in this paper to improve the dynamic response and prediction accuracy in transient-state,while lessening the computational burden and improving the control performance in steady-state.The timescale characteristics of different parts of MPCC,such as signal sampling,prediction calculation,control output,model error correction,are analyzed,and the algorithm architecture of MPCC with multi-timescale is proposed.The difference between reference and actual speed,and the change rate of actual speed are utilized to discriminate the transient state of speed change and load change,respectively.Adaptive-adjusting method of control period and prediction stepsize are illustrated in detail after operation condition discrimination.Experimental results of a PMSM are presented to validate the effectiveness of proposed MPCC.In addition,comparative evaluation of single-step MPCC with fixed timescale and proposed MPCC is conducted,which demonstrates the superiority of proposed control strategy.