Speed Regulation Method Using Genetic Algorithm for Dual Three-phase Permanent Magnet Synchronous Motors

Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.

Zero-sequence Current Suppressing Strategy for Dual Three-phase Permanent Magnet Synchronous Machines Connected with Single Neutral Point

Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM)strategy to suppress the ZSC.Five vectors are selected as basic voltage vectors in one switching period.The fundamental and harmonic planes and the zero-sequence plane are taken into consideration to synthesis the reference voltage vector.To suppress the ZSC,a non-zero zero-sequence voltage(ZSV)is generated to compensate the third harmonic back-EMF.Rather than triangular carrier modulation,the sawtooth carrier modulation strategy is used to generate asymmetric PWM signals.The modulation range is investigated to explore the variation of modulation range caused by considering the zero-sequence plane.With the proposed method,the ZSC can be considerably reduced.The simulated and experimental results are presented to validate the effectiveness of the proposed modulation strategy.

Electromagnetic Performance Prediction for the Symmetrical Dual Three-phase Surface-mounted PMSM under Open-phase Faults Based on Accurate Subdomain Model

The paper presents an accurate analytical subdomain model for predicting the electromagnetic performance in the symmetrical dual three-phase surface-mounted permanent magnet synchronous machine(PMSM)under open-phase faulty conditions.The model derivations are extended from previous accurate subdomain models accounting for slotting effects.Compared with most conventional subdomain models for traditional three-phase machines with nonoverlapping winding arrangement,the subdomain model proposed in this paper applied for the 24-slot/4-pole dual three-phase machine with symmetrical overlapping winding arrangement.In order to investigate the postfault electromagnetic performance,the reconfigured phase currents and then current density distribution in stator slots under different open-circuit conditions are discussed.According to the developed model and postfault current density distribution,the steady-state electromagnetic performance,such as the electromagnetic torque and unbalanced magnetic force,under open-circuit faulty conditions are obtained.For validation purposes,finite element analysis(FEA)is employed to validate the analytical results.The result indicate that the postfault electromagnet performance can be accurately predicted by the proposed subdomain model,which is in good agreement with FEA results.

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.

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.

Small Signal Stability of Three-phase and Six-phase Synchronous Motors:A Comparative Analysis

Small signal stability analysis is conducted for an asymmetrical six-phase synchronous motor in comparison with its equivalent three-phase counterpart.For this purpose,a linearized model of the six-phase synchronous motor is developed using the dq0 approach,which is used in eigenvalue criteria to determine absolute stability in comparison with its equivalent three-phase counterpart.The analysis includes a comparison of the variation in evaluated eigenvalues associated with the stator and rotor sides according to changes in both the three and six-phase machine parameters and working conditions.Key analytical results are experimentally investigated and validated on a test rig.

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.

Fault-tolerant stator flux oriented decoupling control for dual three-phase permanent magnet motor without diagnosis and reconfiguration

In this paper,the fault-tolerant capability of the existing stator-flux-oriented decoupling control(SFOC)for the DTP-PM motor is investigated,and a simple fault-tolerant SFOC is further designed to enhance fault tolerance.Firstly,the mathematical model of the DTP-PM motor in the stator-flux-oriented rotating coordinate system is analyzed.An SFOC is proposed to guarantee healthy operation performance,considering torque,flux linkage,and harmonic currents.Secondly,the coupling relationship under open-phase conditions is assessed.The assessed result shows that the coupling relationship between the harmonic and fundamental components results in conflicts and poor post-fault operation.Thirdly,the proposed SFOC includes an automatic deactivation module to detect conflicts with a variable threshold.The conflicted harmonic current controllers can be excluded automatically.Hence,fault-tolerant control can be remedied without diagnosing the specific fault scenario,and excellent faulttolerant capability can be achieved.Finally,experiments on a DTP-PM motor are carried out to verify the feasibility and effectiveness of the proposed strategy.

Transient Analysis and Control Strategies for a Quad-lnverter Multiphase Multilevel Motor Drive in Faulty Conditions

In this paper, post-fault-tolerant control strategies for quad-inverter multiphase-multilevel induction motor drives are investigated. More specifically, four standard two-level three-phase VSIs （voltage source inverters） supplying the open-end windings of a dual three-phase induction motor is considered, quadrupling the power capability of a single VSI with given voltage and current ratings. In healthy conditions, the control algorithm is able to generate multi-level voltage waveforms, equivalent to the ones of a three-level inverter and to share the total motor power among the four dc sources in each switching period. This sharing capability is investigated under post-fault operating conditions, when one VSI must be completely insulated due to a severe failure on it. In this case, the conversion power unit can operate with a reduced power rating by a proper modulation of the remaining three VSIs. The whole ac motor drive has been numerically implemented, and the effectiveness of the proposed control strategies under healthy and post-fault operating conditions have been proved.

双三相同步磁阻电机单相开路故障下的容错控制策略

双三相同步磁阻电机(dual three-phase synchronous reluctance motor,DTP-SynRM)转子不含永磁体,没有高温退磁风险,成本较低,且由于其系统自由度高、冗余性强,因此具有较好的容错性能。开路故障是双三相同步磁阻电机系统中最常见的故障类型之一,该文针对一种两套三相绕组中性点相互独立的双三相同步磁阻电机单相开路故障,建立DTP-SynRM矢量空间解耦模型,实现对电压、电流和磁链方程的完全解耦。在开路故障状态下仍将其视为一个正常的双三相电机,分析故障状态对电机的电流约束和信号传递的影响,并指出在开路故障下z2轴电流与β轴电流不再独立,电机由正常运行时的四阶系统降阶为三阶系统,而由于开路故障导致的电压信号传递不准确则会在dq坐标系中引入二次谐波电流,并产生二次和四次转矩波动。该文提出一种同时考虑电流约束和信号传递误差的故障容错方法,电机处于三闭环运行状态,补偿电压信号传递误差,抑制开路故障时电机的转矩波动并降低电流谐波。搭建实验平台进行实验,验证所提容错方法的有效性和可行性。

双并列转子永磁同步电机转矩脉动产生机理及抑制

双并列转子永磁同步电机由于部分定子铁心和绕组的缺失,存在较大的转矩脉动,限制了其在并行对驱类机械装备中的应用。该文对双并列转子永磁电机转矩脉动产生机理进行分析,并提出了相应的抑制方法。对比了N-N型、N-S型两种转子结构,阐明了N-S型转子结构的优越性。在此基础上,开展了转矩脉动产生机理研究,按照影响因素不同,逐次分析了齿槽效应、端部效应、永磁齿轮效应以及绕组参数不对称对电机转矩脉动的作用机理,构建了各个转矩分量的解析表达式。通过有限元模型,验证了理论分析的正确性。针对产生转矩脉动的不同分量,提出了相应的抑制方法,其中抑制空载转矩可以通过优化电机的结构参数来实现,抑制纹波转矩可以通过优化绕组位置分布来实现。搭建样机实验平台,验证了分析模型的准确性。

基于双侧电机同步转速调节的履带机器人直行控制研究

由于路面阻力不均衡使履带机器人双侧电机负载扰动不一致,造成两侧电机转速不同步,导致直行运动跑偏。因此,需要提高双电机的转速同步性能。针对路面扰动等因素,考虑到滑模控制算法对参数变化不敏感,且能够抑制一定范围内的不确定扰动。故基于交叉耦合控制方法加入滑模同步控制算法进行改进。将传统交叉耦合控制方法和改进的交叉耦合滑模同步控制方法进行对比仿真和实验。结果表明,突变扰动下,改进后同步误差和直行跑偏量得到明显减小,同步直行性能有了显著提高。

刚性联接双电机系统功率平衡控制策略

针对刚性联接双电机系统因参数摄动和负载变化导致的系统输出功率不均衡问题,基于转矩闭环矢量控制系统,提出了一种自抗扰模型预测(ADRC-MPCC)转矩交叉耦合功率平衡控制策略。首先,建立刚性联接双电机系统的统一数学模型,基于该模型分析了功率不平衡产生的原因;其次,通过确定合适的转矩反馈补偿系数,提高了系统中双电机的同步性能;最后,设计自抗扰控制器对转速环、磁链环和转矩环的扰动进行估计和补偿,并通过简化模型预测控制方法对逆变器开关状态进行选择,减少了控制器的运算时间。仿真与实验结果表明,提出的控制策略实现了参数摄动和负载扰动情况下刚性联接双电机系统的输出功率平衡,验证了功率平衡控制策略的有效性。

小偏差永磁同步电机双矢量模型预测控制

传统的永磁同步电机双矢量模型预测控制的合成电压矢量与参考电压矢量的偏差较大,且存在计算量大、开关频率高的缺点,在实际工况中难以实现良好的控制性能。为了解决上述问题,提出一种小偏差永磁同步电机双矢量模型预测控制策略,通过分析参考电压矢量的变化规律,构造新的电压矢量选择表,将电压矢量的选择范围从六个降为三个,减小计算量的同时也降低了开关频率;针对传统的作用时间计算方法存在的问题,提出基于偏差最小原则的作用时间计算方法,并详细证明了该方法的优越性。仿真和实验结果显示,所提出的方法能够有效减小计算量和降低开关频率,同时具有较好的稳态和动态性能。

双三相永磁同步电机改进型模型预测电流控制

针对双三相永磁同步电机模型预测共模电压抑制方法存在寻优计算量大、开关频率较高、稳态性能不佳的问题,提出一种改进型模型预测电流控制.首先,改进六相两电平逆变器,降低零矢量共模电压幅值;其次,选择小共模电压矢量构造虚拟电压矢量,简化价值函数的同时减小共模电压和电流谐波含量;再次,通过计算参考电压矢量直接选择最优电压矢量以减少寻优次数,并引入占空比控制提升电机控制精度,改善电机稳态性能.最后,仿真对比传统模型预测电流控制、RCMV(Reduced Common Mode Voltage)-1、RCMV-2和所提控制方法.结果表明,所提控制方法在减小共模电压的同时,降低了转矩脉动和谐波电流,且较RCMV-2方法开关频率明显降低;此外,寻优代码执行时间相较于RCMV-1和RCMV-2分别降低了约91%和65%,减小了计算量.

双液压马达驱动的甘蔗根切器刀盘转速同步控制方法

为简化双刀盘甘蔗根切器的传动链,提高传动系统对时变载荷的适应性,该研究提出用双液压马达直接驱动双刀盘,并将电液比例负载敏感技术应用于根切器的传动方案,通过建模仿真和试验探究双刀盘同步精度的控制方法。建立根切器电液比例阀控马达闭环速度控制系统的传递函数,分析得到该系统的稳定裕度仅为16.5°,因此需要采用合适的控制算法提高系统的稳定性和控制精度。基于AMESim-MATLAB联合仿真,研究采用主从控制策略,主马达为PID控制,从马达分别采用PID、自适应模糊PID和滑模变结构控制算法时系统的稳定性和刀盘转速的控制精度。仿真结果为:不同控制算法下马达开启过程转速的动态调整时间分别为5.5、3.0、2.7 s,稳态阶段两个液压马达的速度差分别为20、8、5 r/min;最后搭建试验台,以实测载荷谱为负载输入,进行主从马达转速同步控制试验,得到PID、自适应模糊PID和滑模变结构控制系统启动阶段转速的动态调整时间分别为6.3、4.6、3.7 s,稳态阶段主从马达的转速差分别为47、23、13 r/min;仿真与试验结果均表明,基于滑模变结构算法的刀盘转速同步控制系统的各项指标均优于PID和自适应模糊PID控制。研究结果可为甘蔗收割机根切器传动与控制系统的优化设计提供理论参考。

基于参数扰动估计的双三相永磁同步电机鲁棒模型预测控制

双三相永磁同步电机因其损耗小、效率高、容错能力强等特点,广泛应用于航空航天技术、电动汽车等领域。为优化双三相永磁同步电机控制性能,采用双d-q坐标变换对双三相永磁同步电机进行数学建模,为减小电流纹波,在传统模型预测电流控制策略基础上,增加延时补偿;考虑电机参数扰动的影响,提出一种能够对参数进行在线估计的滑模观测器,以提高控制系统鲁棒性,最后在MATLAB/Simulink中进行系统抗负载扰动与鲁棒性能仿真分析。仿真结果表明,改进后的控制策略提高了电机的响应速度,超调减小,系统对电机参数扰动的敏感性减弱,系统抗负载能力和鲁棒性增强。

低载波比下的双三相永磁电机低电流纹波 变开关序列调制策略

双三相永磁同步电机适用于大功率牵引和传动系统,但系统需要运行在低载波比工况,导致电机电流纹波占比上升,电流质量下降,影响输出效率。因此,文中提出低载波比下考虑电流纹波抑制的双三相永磁同步电机变开关序列调制策略。首先,推导出双三相电机电流纹波计算通式,比较传统四矢量调制策略和三相解耦调制策略的电流纹波大小;随后,在三相解耦调制基础上,调整开关序列,通过分散矢量作用时间的方式降低了电流纹波峰值;此外,为了使电流纹波在整个电周期内维持较低水平,采取扇区细分的方式,对调制策略进行切换;最后,实验结果证明,所提方法能够提升电流正弦度,降低电流纹波和电机损耗。

分段式双三相永磁直线同步电机的无模型电流预测控制

分段式结构的双三相永磁直线同步电机(PMLSM),动子穿入和穿出定子分段时,传统的无差拍预测电流控制(DPCC)易受反电动势动态扰动的影响,无法实现精确的电流跟踪和推力控制。同时,该电机模型的参数失配会增大DPCC电流和推力控制的难度。针对以上问题,该文提出了一种基于无模型电流预测控制(MFPCC)的电流控制策略。首先,构建了分段式双三相PMLSM的超局部模型。其次,基于该超局部模型设计了预测电流控制器,并设计扰动观测器以补偿反电动势动态扰动和参数失配的影响。最后,实验验证了所提MFPCC能够抑制分段式双三相PMLSM的反电动势和参数失配的扰动,有效提升参数鲁棒性、电流跟踪性能并降低推力波动。

基于主动式阻尼的混合式步进电机转速振荡抑制控制

混合式步进电机因其特殊的机械结构导致自身阻尼极小,在实际运行过程中会发生振荡过大,甚至失步的问题。为提高混合式步进电机的控制品质,提出一种基于主动式阻尼的步进电机转速振荡抑制方法。首先,将电机模型转化至同步旋转dq坐标系,将电流i_d控制恒为额定电流,利用位置误差和速度误差调节电流i_q生成瞬时转矩,抑制电机运行时存在的振荡现象。其次,为实现电机闭环反馈控制,提出一种将同步频率提取滤波器(SFF)与三阶锁相环(PLL~3rd)相结合的无传感器控制方法。SFF可以滤除反电动势信号中的高次谐波,PLL~3rd能消除转速变化过程中的稳态误差。实验证明,该方法有效抑制了步进电机运行过程中的振荡现象,提升了电机的运行品质。