Topology Optimization of Rotor Pole in Switched Reluctance Motor for Minimum Torque Ripple

Torque ripple is a major problem for switched reluctance motors, which may cause undesirable vibration and acoustic noise, especially at low speed. This paper presents an optimal topology structure of rotor for 8/6 pole switched reluctance motor by using the level set method. The nonlinear ferromagnetic material boundary of rotor pole is implicitly represented through an embedded level set function. This method is applied to obtaining the optimal distributions of material in the design domain for minimizing torque ripple and maximizing average torque. In the optimization objective function, the reluctivity of ferromagnetic material is selected as the design variable. The normal velocity is derived from sensitivity analysis, where the adjoint variable method is utilized. Two-dimensional finite element method is employed to calculate the electromagnetic parameters of this electric machine. Analysis results obtained from the transient simulation of electromagnetic field coupled with control circuit show that the torque ripple is reduced effectively by using the optimized rotor structure.     

基于拓扑优化的单边核磁共振永磁磁体研究

为了在单边核磁共振仪器外产生梯度恒定的磁场，提出利用基于拓扑优化和有限元法的优化设计方法。通过伴随变量法推导出永磁系统中拓扑设计灵敏度的解析表达式，在连续性拓扑灵敏度分析的基础上，利用罚函数法来优化单边核磁共振仪器永磁磁体的磁化方向。数值结果表明，提出的优化方法能使单边核磁共振仪器外产生梯度恒定的磁场。     

Optimal Design of Buffer Material in the Geological Disposal of Radioactive Wastes Using the Satisficing Trade‐off Method and a Self‐Organizing Map

In this paper, we consider the use of a multi‐objective optimization method in order to obtain a preferred solution for the buffer material optimal design problem in the high‐level geological disposal of radioactive waste. The buffer material optimal design problem is formulated as a constrained multi‐objective optimization problem. Its Pareto optimal solutions are distributed evenly over the entire feasible region. Hence, we develop a search method to find a preferred solution easily for a decision maker from the Pareto optimal solutions, which are distributed evenly and broadly. In the preferred solution search method, a technique for visualization of a Pareto optimal solution set using a self‐organizing map is introduced into the satisficing trade‐off method, which is an interactive method for obtaining a Pareto optimal solution that satisfies a decision maker. We confirm the effectiveness of the preferred solution search method in the buffer material optimal design problem. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(2): 17–32, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22634     

Layout optimization method for magnetic circuit using multistep utilization of genetic algorithm combined with design space reduction

Layout optimization with ON/OFF information of magnetic material in finite elements is one of the most attractive tools in the initial conceptual and practical design of electrical machinery for engineers. Heuristic algorithms based on random search allow engineers to define general‐purpose objects. However, there are many iterations of finite element analysis, and it is difficult to achieve a practical solution without island and void distribution by using a direct search method, such as simulated annealing (SA), genetic algorithm (GA), and so on. This paper presents a layout optimization method based on GA. The proposed method can arrive at a practical solution by means of multistep utilization of the GA, and the convergence speed is considerably improved by using it in combination with reduction of the design space. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 19‐30, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22290     

E型铁心开关磁通电机的电磁性能解析计算

由于复杂磁路的影响,开关磁通电机电磁性能的解析计算是个难点。采用子域法,通过子域划分、建立偏微分方程与通解、确立边界条件和积分常数求解等步骤建立E型铁心结构开关磁通电机的解析模型,计算得到了各子域矢量磁位、磁通密度、绕组磁链、电动势和电磁转矩,分析了不同定转子极数组合对绕组电动势和齿槽转矩的影响,得到了合适的极数组合。与有限元法计算结果的对比表明,空载时两者计算结果非常接近,负载时由于电枢反应磁场的影响,与非线性有限元相比,解析法会带来一定误差。虽然该解析模型不能考虑饱和的影响,由于解析法计算速度快,能得到规律性的结论,非常适合电机的初始设计和优化计算。     

基于参数敏感度的双凸极永磁型双定子电机的优化设计和性能分析

双凸极永磁型双定子(DSPMDS)电机是针对电动汽车(EVs)驱动电机的应用要求,融合了双定子电机理论和定子永磁型双凸极电机理论,具有高转矩密度、高功率密度以及更加灵活多变的工作模式等优点。针对该电机双层气隙、双定子的复杂结构,在DSPMDS电机初始设计尺寸的基础上,通过建立电机参数化模型,并采用多目标敏感度优化方法,筛选出对电机转矩波动和铁心损耗影响最大的关键结构尺寸参数,在此基础上进一步采用响应面法选取最优结构尺寸参数。采用有限元仿真计算分析DSPMDS电机的反电动势、铁心损耗、定位力矩等电磁性能,样机实验结果验证了所提出的参数敏感度优化设计方法和性能分析的正确性,丰富了该类复杂结构的永磁型电机的快速设计和优化的途径。     

An investigation of topology optimization for 3D magnetic shielding problems

Novel approaches to the 3D optimal design of magnetic shields are presented, in which topology optimization is achieved with the aid of numerical magnetic field analysis. The numerical procedures are implemented by means of a genetic algorithm combined with hybrid finite element and boundary element methods. This results in an overall increase in the optimization speed with acceptable computational accuracy. Finally, we present numerical results that demonstrate the validity of the proposed approach. © 1998 Scripta Technica. Electr Eng Jpn, 122(3): 55–61, 1998     

基于遗传算法的车用永磁电机转子尺寸多目标优化设计

新能源汽车(NEV)驱动电机对于转矩密度、功率密度、转矩脉动、振动噪声和高效率区间等参数有着较为严格的性能要求。转子拓扑及其结构尺寸直接影响电机的磁场大小、磁场分布和谐波磁场含量,对于汽车电机性能起着重要影响。针对该类电机多工况多性能参数的特点,利用有限元软件建立主要工况的电磁场计算模型,确定需要优化的转子结构尺寸。根据车用电机的主要性能指标,以转矩脉动、齿槽转矩、气隙反电动势谐波畸变率和输出转矩作为优化目标,根据不同工况性能需求定义目标函数,选择遗传算法作为多目标优化设计算法,再根据优化计算结果进行方案筛选,最终确定电机的最优转子尺寸。该优化设计方法可快速确定车用永磁电机的最优电磁设计方案,丰富了该类电机的高效优化设计途径。     

大型感应电动机的离散优化设计

本文提出大型三相感应电动机的离散优化设计方法。以改进的分析程序为基础，结合电机主要尺寸方程式和电磁参数统计平均值给出初始点，采用离散规划优化方法求解，取得了较满意的结果。     

基于有限元技术的低压电器拓扑优化设计研究

以变密度法作为材料的插值模型，最小柔度作为目标函数，优化准则作为优化算法，阐述了利用有限元技术进行结构拓扑优化的过程。以低压电器产品为例，开展了拓扑优化设计研究。结果表明，拓扑优化可大幅降低零件质量而不损失零件强度，为降低成本提供了一种有效方案。     

大型异步电动机的离散优化设计

本文提出了大型三相异步电动机的离散优化设计方法，以改进的分析程序为基础，结合电机主要尺寸方程式和电磁参数统计的平均值，给出了补始点，采用离散规划优化方法进行求解，取得了较满意的结果。     

Multiobjective optimum design method with anti‐demagnetization of high‐density permanent magnet synchronous motor

This paper presents a method of multiobjective optimization design with anti‐demagnetization aiming at the problem of irreversible demagnetization in high‐density permanent magnet synchronous motors (PMSMs) due to temperature and external magnetic field, at the same time considering the volume of permanent magnets and cost, torque ripple, and core loss. In the first step, a two‐dimensional magnetic network model is used to rapidly assess the basic design parameters and its ability to avenge the anti‐demagnetization of the PMSM. In the second step, the finite element method (FEM) is used to design the key parts of motor, and regression models that solve the model of the multiobjective problem are built based on the simulation experiment data. On this basis, multiobjective optimization result using genetic algorithm is used that can achieve a fast and efficiently global optimal solution. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

考虑障碍区影响的海上风电场集电系统拓扑设计

对于海上风电场集电系统的优化设计,现有设计方法大部分只考虑了电缆和开关的合理配置,而没有充分考虑障碍区对拓扑设计的影响。为此,本文提出了一种考虑障碍区影响的海上风电场集电系统拓扑优化设计方法。采用GIS技术对障碍区进行图层化处理,并利用最小面积不定形包围盒法将障碍区表示为最小面积矩形包围盒。在此基础上,结合Dijkstra算法与Prim算法的优点可得求取避障路径的优化算法,再通过基于层次分析法且兼顾经济性和可靠性两个方面影响因素的模糊综合评价模型来比较海上风电场集电系统的拓扑方案,就可完成海上风电场集电系统的最优拓扑设计。最后的算例及分析验证了本文算法的可行性。     

Adjoint-Based Design Optimization of Nonlinear Switched Reluctance Motors

Abstract

This work investigates the application of the adjoint variable method (AVM) to switched reluctance motors (SRMs). A MATLAB toolbox developed by the authors estimates the sensitivities of the required objective function with respect to different geometric design parameters using at most one adjoint simulation. In this work, the AVM evaluates the sensitivities of the x and y components of the magnetic flux density, the phase flux linkage, and the electromagnetic torque of switched reluctance motors with respect to teeth height, yoke thickness, teeth pole arc angle, and teeth taper angle of both stator and rotor. The nonlinearity of the motor magnetic material is taken into consideration. The estimated sensitivities using AVM are compared with those obtained using the more accurate but time intensive central finite differences (CFD). An interior-point optimization algorithm utilizes the sensitivities of the electromagnetic torque of an SRM to maximize the motor static torque profile. Structural mapping technique is used to control the geometric design parameters through the optimization process.     

新型永磁调磁式磁齿轮的设计与优化

为了提高磁齿轮的输出转矩和运行转速、减小永磁体的涡流损耗,提出一种新型永磁调磁式磁齿轮,分析其工作原理和转矩特性,结果表明相比较传统的磁齿轮,新型永磁调磁式磁齿轮具有传动效率高、转矩密度高、可高速传动的优点。在此基础上,为了获得新型磁齿轮的最优结构参数,以提升输出转矩和减小齿槽转矩为优化目标,提出一种基于参数敏感性和响应面法相结合的多目标优化方法,对新型磁齿轮的永磁调磁块、外转子及内转子永磁体等结构参数进行优化设计,利用有限元法分析优化前后新型磁齿轮的电磁性能,表明多目标优化方法可进一步提升新型磁齿轮的输出性能,为其应用和优化设计奠定了基础。     

计及分布式电源动态行为的配电网重构优化策略

解决分布式电源高渗透率地区电压越限的根本方法是实施合理的配电网规划。现有方法存在着人工智能算法初始域搜索半径过大以及动态时段划分与拓扑寻优分离的问题。引入半不变量法计算随机潮流来处理分布式电源动态行为带来的不确定性,并采用改进的NSGA-II算法实现配电网重构,提出了一种计及分布式电源动态行为的配电网重构概率约束优化策略和求解方法。特别提出了在网架寻优的基础上再在时间层面上依据优压参数再次整合优化来构建配电系统动态重构数学模型,最后采用嵌套基因回路搜索策略改进NSGA-Ⅱ算法并求解上述优化模型,以解决传统配电网规划中对强相关性随机变量考虑较少的不足。IEEE-33节点配电系统算例验证了所提方法的有效性。     

Initial rotor position estimation of interior permanent magnet synchronous motor using optimal voltage vector

The initial rotor position estimation is a serious problem affecting sensorless drives of permanent magnet synchronous motors. This paper presents an estimation method of initial rotor position for interior permanent magnet synchronous motors. The principle of the estimation is based on the nonlinear magnetization characteristics of the stator core caused by the magnet of the rotor. The estimation is performed using the variation of the current response caused by the magnetic saturation when the voltage vector is applied to the motor. This method can be performed without motor parameters and any additional hardware. Decision method of the optimal voltage vector applied to the motor is also proposed to accurately implement the estimation. Experimental results show that the initial rotor position can be estimated without rotating the rotor by using the optimal voltage vector. It is found that the average of the estimation error is ±1.34 electrical degrees, and the estimation is completed within 15.2 ms in the test motor. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(4): 69–76, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20062     

基于遗传算法的双E型永磁接触器仿真优化设计

在详细分析永磁操动机构模型和相关理论的基础上,给出了永磁接触器操动机构的设计方法。基于磁路法获得永磁操动机构的初始设计参数,建立永磁操动机构最优化模型。采用遗传算法并结合电磁场有限元计算方法求解该最优化模型,获得合理的设计参数,并研制了1台250A配双E型永磁操动机构的永磁接触器。试验结果表明,算法可实现永磁接触器的优化设计,大幅度提高产品的设计效率,验证了设计模型和算法的有效性与正确性。     

基于Taguchi-PSO的永磁同步发电机空载气隙磁密波形优化

以某款增程器用48 V永磁同步发电机(PMSG)的空载气隙磁密波形畸变率为优化目标,永磁体极弧系数、气隙长度、磁钢厚度、磁极偏心距为变量,磁钢质量和电机效率为评价参考指标,利用RMxprt参数化扫描功能和Taguchi方法建立正交试验矩阵,ANSYS Maxwell二维有限元仿真分析得到数据样本。通过傅里叶模型拟合样本数据,构造适应度函数。最后,采用粒子群算法(PSO)进行寻优,得到了一组最优的磁钢参数并进行有限元验证。结果表明,采用Taguchi-PSO方法,使空载气隙磁密波形得到了较大改善,并减少了磁钢用量。     

Square‐root domain wave filters

In this paper the wave method is used for designing high‐order square‐root domain filters, which emulate the topology of the corresponding LC ladder prototypes. This is achieved by transposing the signal flow graph that corresponds to the wave equivalent of the elementary two‐port subnetwork in the linear domain to the corresponding one in the square‐root domain, by employing an appropriate set of complementary operators. As the equivalents of the other reactive elements are derived from the wave equivalent of the elementary subnetwork, by interchanging the terminals of the appropriate wave signals and/or using inverters, an advantage offered by the proposed technique is the modularity of the derived filter configurations. As an example, a fifth‐order lowpass square‐root domain wave filter was designed and its behaviour was studied through simulation results in order to demonstrate the validity of the proposed design technique. Copyright © 2006 John Wiley & Sons, Ltd.