In this paper, a magnet shaping method based on microelement, applicable to both circular and non-circular boundaries, is proposed. Firstly, the relationship between air gap flux density and torque is deduced. The microelement concept is introduced into the magnet shaping method. The permanent magnet pole can be considered as an assemble of cells distributed along the circumference. The air gap flux density produced by each cell could be analyzed by Fourier transform. By adjusting the parameters of each cell, the specific harmonics amplitude of the air gap flux density can be changed. With this method, the optimal magnet shape to minimize permanent magnet usage without deteriorating the output torque is derived for surface permanent magnet synchronous machines with both circular and non-circular boundaries. Then, a 24-slot 8-pole surface permanent magnet synchronous machines with conventional tile-shaped permanent magnet is chosen as the baseline machine. The machines with tile-shaped permanent magnet and the proposed leaf-shaped permanent magnet are optimized. Furthermore, comprehensive electromagnetic performance comparisons of three machines are carried out by finite element analysis. It is proved that the two machines compared to the baseline motor could achieve reductions in permanent magnet usage of 2% and 7% respectively, while maintaining the same average torque. Finally, the prototype with the proposed leaf-shaped permanent magnet is fabricated, and extensive experiments are conducted. The simulation results are experimentally verified.

The enhancement of torque density has emerged as a significant area within the research of permanent magnet (PM) drive motors. The Unequal Tooth Width (UNET) stator configuration in certain permanent magnet brushless motors has been adopted to improve the torque density. Traditional electrical machinery theory predominantly focused on the fundamental winding factor; however, it is needed to refine the comprehensive general formula for the winding factor associated with UNET. Existing literature indicates that the enhancement in torque density often surpasses the rise of the fundamental winding factor, particularly in the context of interior PM machines. The underlying principles of the aforementioned regular phenomenon is explored in this paper. The study investigates harmonic components beyond the fundamental value of the winding factor in a UNET Interior PM Synchronous Motors (UNETIPMSM). A frozen permeability model of stator core is developed, and the field modulation effect in the UNETIPMSM is elucidated. The findings suggest that the actual winding factor comprises a series of harmonics corresponding to the working pole pairs of the air gap flux density, which can bring additional torque in the UNETIPMSM. The analysis is corroborated through finite element analysis (FEA) and experimental results.

This manuscript presents an advanced sensorless control strategy for Permanent Magnet Synchronous Motors (PMSMs) designed to address the challenges posed by cross-saturation effects and magnetic field distortions. The research focuses on fractional slot concentrated winding interior PMSMs, which are particularly prone to inductance parameter variations due to magnetic saturation and cross-coupling. To tackle these issues, a comprehensive analysis of the inductance parameter impact on position estimation error is conducted. Using finite element analysis (FEA), we carefully simulate the motor’s inductance, considering magnetic saturation and cross-coupling effects. These results are used in a sliding mode observer (SMO) for sensorless control, which is tuned with a phase-locked loop (PLL) to improve position estimation accuracy throughout the motor’s operating range. The low-speed startup is efficiently managed through an I/F initiation method, transitioning to the improved SMO and PLL for medium to high-speed operations, thereby achieving precise sensorless control. Extensive simulations substantiate the method’s feasibility and robust performance.

The Doubly Salient Electromagnetic Motor (DSEM) has a promising application prospect in fields such as new energy vehicles. However, the field windings of DSEM brings high copper loss, and traditional converter topologies and control methods limit the improvement of motor efficiency. In this paper, to improve the efficiency of a four-phase 8/6 pole DSEM, a current coordinated control strategy based on five-leg converter is proposed. This strategy achieves coordinated control of the DSEM positive and negative phase currents and field current by controlling the five-leg switches. Based on the working principles of the converter, the relationship between phase current, field current, and average electromagnetic torque is established through magnetic co-energy. The minimum copper loss current combination is obtained using the Lagrange multiplier method, and a speed closed-loop control is established. Simulation results show that compared with the conventional symmetrical current control, the motor efficiency increases 2.8

To solve the problem of poor steady-state performance of the duty cycle model predictive current control (DC-MPCC) for permanent magnet synchronous motor (PMSM) and the problem of a large amount of calculation of the dual vector model predictive current control (DV-MPCC), the improved dual vector model predictive current control (IDV-MPCC) is proposed. All the voltage vectors are divided into two vector sets according to the error of all the candidate voltage vectors corresponding to the predictive current and the reference current, and one voltage vector is selected from each of the two vector sets for each control period. According to the simulation results, the steady-state performance of IDV-MPCC at low speed is similar to that of DC-MPCC and DV-MPCC. The q-axis current ripple and torque ripple of IDV-MPCC are obviously improved when the speed increases, and the amount of calculation decreases compared with DV-MPCC. On this basis, a control strategy is proposed to switch between DC-MPCC and IDV-MPCC according to the speed, which can maintain a good steady-state performance in a wide range of speed changes while reducing the amount of calculation at low speed.

Compared with traditional permanent magnet synchronous machines (PMSM), the Interior Permanent Magnet Synchronous Machine with Unequal Tooth Widths (UNETIPMSM) offers advantages such as high torque density and good fault tolerance. However, this also leads to an increase in torque ripple. To suppress the torque ripple of UNETIPMSM, a method of stator/rotor auxiliary slots was studied. The mechanism of torque ripple generation in permanent magnet synchronous motors was analyzed. A finite model of a 10-pole/12-slot motor is established to perform electromagnetic simulation. Three types of auxiliary slots are proposed, with notching the armature tooth, fault-tolerant tooth, and both the armature and fault-tolerant tooth. Additionally, the effects of the slot width and depth of rotor auxiliary slots on torque ripple are investigated, and three auxiliary slot structures are compared. The results indicate that appropriately designed auxiliary slots on the stator and rotor can effectively reduce torque ripple while maintaining the motor’s performance.

This paper proposes a novel permanent magnet synchronous motor (PMSM) with stepped magnetic poles to improve utilization of the rare-earth PM material without deteriorating the torque performances. Initially, the simplified model is introduced for elucidating the air gap flux density generated by the proposed stepped PM topology. The relationship between the parameters of the stepped magnetic poles and the air gap flux density is analytically derived and confirmed. Subsequently, the parameters of the stepped magnetic poles are optimized to minimize PM consumption while achieving the desired fundamental harmonic of air gap flux density. Furthermore, the skew slot is adopted to mitigate torque ripple. Electromagnetic performances of the two machines, including no-load characteristics and torque characteristics, are analyzed and compared by finite element analysis (FEA). It is found that the proposed motor can reduce the permanent magnet by 5.1% under the premise of generating the same electromagnetic torque, and the torque ripple is also reduced. Finally, the proposed stepped PMSM is prototyped and measured to validate the analysis.

The ability to reduce operational losses and achieve higher efficiency is critical for transportation electrification applications. Doubly salient electromagnetic motors (DSEMs) have been increasingly seen as an option for electric vehicle traction. However, the efficiency of DSEMs is limited due to notable copper loss. In this paper, to improve the efficiency of DSEMs, an optimal current control (OCC) strategy based on minimum copper loss is proposed and verified. By analyzing the different contributions to the torque made by positive and negative phase currents respectively, the necessity of introducing the asymmetric phase current control method is explained. The main novelty of the paper is that the proposed OCC strategy not only adopts asymmetric phase current control but also regulates the field current coordinately. With the i-ψ curve and Lagrange multiplier method, the optimal field and armature current combinations are obtained to minimize the copper loss. In addition, in terms of the torque deterioration caused by the limited phase current variation rate, the advanced angle control (AAC) method is adopted. Compared with the conventional control method, the system efficiency of DSEM with OCC under AAC increases from 76% to 80%, and the motor efficiency increases from 80% to 86%.

Doubly salient electromagnetic motors (DSEMs) have the advantages of simple structure, adjustable field, and flexible control. However, its doubly salient structure may cause large torque fluctuations, and the field winding and armature winding also induce additional copper losses. Aiming at the above problems, this paper proposes a new control strategy based on Torque Sharing Function (TSF). The improvement of this paper is that by analyzing the shortcomings of traditional TSF, the phase torque is controlled asymmetrically and the excitation current is controlled according to the working mode of DSEM. By establishing an optimization model with copper loss as the objective function, the optimal distribution combination of different types of phase torque and field current is obtained. Compared with the traditional TSF, the simulation results show that the proposed method can effectively suppress the motor torque ripple and reduce the copper loss.

三相横向磁通永磁电机采用无位置传感器控制时,和永磁同步电机类似,位置偏差主要受到模型参数误差以及逆变器非线性等因素影响.该文依据估计直轴电流为 0 时的位置偏差方程,提出一种稳态工况下注入电感扰动的参数辨识方法以修正位置误差.该方法通过对观测器所用电感值施加扰动,构建非线性方程组,采用列文伯格-马夸特法求解,实现电感及永磁体磁链的准确辨识,并将辨识结果应用到观测器中,从而改善了无位置传感器运行的位置精度.仿真与实验结果验证了该方法的可行性与有效性.

混合励磁双凸极电机具有结构简单、功率密度高的特点,适用于航空电源系统.本文首先简要介绍了一种新型轴向混合励磁双凸极电机的结构特点,搭建电机有限元模型,确定电机初始设计参数,并根据磁链最大原则,通过田口正交优化方法,筛选出关键结构尺寸参数;然后采用中心复合设计试验,在设计空间内建立响应面模型;最后利用自适应遗传算法基于响应面模型进行全局最优点求解.有限元分析结果表明,优化后的电机磁链及反电势均有所提高,表明该优化方法的正确性.

270 V高压直流体制是现代飞机电源系统的重要发展方向之一.依据高压直流发电机具有自启动和短路电流限制能力的要求,提出了轴向混合励磁双凸极发电机,在对基本结构和工作原理进行描述的基础上,通过磁路分析得到了电机气隙磁场随励磁电流的变化规律,并采用有限元仿真加以验证,详细分析了电机的磁场分布、磁链、反电势、输出电压及负载特性等.结果表明,轴向混合励磁双凸极电机相磁链双极性变化,且正弦度高,调磁范围宽,可实现完全灭磁,同时电机运行时效率高,适用于航空高速运行.

在MATLAB/Simulink软件中搭建三级式无刷交流同步发电机调压控制系统模型时,需要选取合适的PI参数使系统的输出电压满足相应的指标.考虑到传统的PI参数整定方法计算复杂,且计算出的参数需要经过多次调整才能满足系统指标,设计了一种基于粒子群(PSO)算法整定PI参数的方法,用以提高三级式同步发电机调压控制系统模型的PI参数整定效率.仿真结果验证了PSO算法整定无刷交流发电系统PI参数的可行性,可以根据需要的输出电压指标整定合适的PI参数.

为了研究电励磁双凸极电机(DSEM)的控制策略,必须建立精确控制模型.DSEM定转子均为双凸极结构,存在明显的边缘效应和高度的局部饱和现象,其磁链和转矩均为电枢电流、励磁电流及转子位置角的非线性函数,难以采用常规方法建立精确控制模型.在深入分析电机电磁特性的基础上,通过有限元仿真分别建立磁链与转矩关于电流与转子位置角关系的数据表.采用Simulink三维查表法,分别对DSEM磁链函数和转矩函数进行建模,并与电压方程一起构成DSEM仿真模型.针对模型各个环节进行了分析验证,以励磁绕组滞环斩波空载反电动势及电枢电流采用不对称控制策略为例,将仿真结果与有限元仿真及试验结果进行了对比,验证了所建模型的精确性、有效性及建模方法的可行性.

横向磁通永磁电机(TFPMM)因结构特殊,存在功率因数低、转矩脉动大等问题,需要改进控制算法来降低电机的转矩脉动,改善控制系统性能.在传统的直接转矩控制(DTC)基础上提出空间矢量调制(SVM)的DTC策略,以改善传统控制策略中电流、磁链控制不精确,转矩脉动大的问题.针对TFPMM齿槽转矩比较大的问题,将电机齿槽转矩拟合成电角度的表达式,补偿到转矩观测器输出端,使转矩观测器能观测齿槽转矩分量,起到抑制齿槽转矩脉动的作用.仿真结果验证SVM-DTC比传统DTC的电流波形更平滑,磁链控制更精确.采用齿槽转矩补偿的方法后电机转矩脉动显著减小,验证了补偿控制算法的有效性.改进的控制算法提高了电机控制系统整体性能.

针对深空通信邻近空间链路的数据通信问题,设计实现了一个基于CCSDS Proximty-1协议的可变窗长自动请求重传系统.通过对传统回退N帧自动请求重传策略进行改进,分析传输帧长、误码率及滑动窗口长度等因素对系统吞吐率的影响,并获得不同误码率条件下的最佳帧长.同时以传输效率为考量,进行了可变滑动窗口长度的设计.仿真结果表明,本文设计的重传系统相比传统固定帧长和窗长的系统,有效提升了数据吞吐率和传输效率,可作为未来火星探测通信的理论参考.

针对深空信道传输距离长、传输时延变化快、接收信号信噪比低、误码率要求高等特点,固定速率传输会对系统吞吐量造成严重影响,很难同时确保通信传输的有效性和可靠性,并根据CCSDS-Proximity-1标准,提出了一种符合协议标准的自适应变速率传输系统设计.该方案可对接收信号进行信噪比估计,通过信噪比估计值判断信道质量,动态的调整收发机的传输速率,保证系统性能满足协议标准.在此基础上,以Xilinx Kintex-7 FPGA为核心进行硬件仿真验证,与固定速率相比,分析比较了自适应系统误码率与吞吐量.实验结果表明,在0dB以上的高斯白噪声中,该自适应数字收发机设计具有较高的吞吐量与较低的误码率,可以有效保障深空信道的有效性与可靠性.

飞机发电机控制器在检测电压有效值时,经常因为频率波动导致有效值计算出现误差.介绍了定频采样算法、过零点算法和准同步采样算法3种有效值算法,在MATLAB软件中进行了对比仿真,选取了误差最小的准同步采样算法.针对准同步采样算法响应时间过长的问题进行了改进,采用半周期积分优化的方法,并适当减少迭代次数.仿真与试验的结果证明,频率在380～420 Hz之间波动时,与传统定频采样算法相比,优化后的准同步采样算法误差从2.63％减小至0.14％.与优化前的准同步采样算法相比,优化后的响应时间从7.42 ms减小至2.46 ms.

在三级式交流发电系统中一般使用传统PID控制器进行调压控制,但是在某些工况下该控制策略难以满足复杂系统的高精度、快响应要求.通过在传统PID控制器的基础上,分析了其不足之处,引入了模糊PID控制策略.同时,针对模糊PID在系统的动态调节过程中论域过小的问题,提出了一种基于变论域模糊控制理论的PID控制器,并与传统双环PID控制和普通的模糊PID控制在MATLAB/Simulink软件中进行对比仿真,验证了该控制策略具有更好的稳态调节精度和动态调节性能,与传统双环PID控制器相比,稳态误差从0.5％优化到0.3％,动态调节时间从0.4 s缩短至0.2s.

为了缩减电机设计周期,该文针对横向磁通永磁电机提出一种非线性动态等效磁网络模型.该模型引入电机饱和深度系数来反映电机不同饱和程度对导磁材料性能的影响.文中着重分析定转子齿和气隙位置磁通管的划分和相应磁阻的计算.在电机转动过程中,根据定转子的相对位置,把电机的一对极范围划分为8个区域,每个区域内的等效磁阻分布均相同.并且用统一的拓扑表示这8个区域的等效磁网络,从而将动态过程转化为静态拓扑.在求得电机磁链的基础上,对电机的电感、空载反电势进行分析计算.最后通过有限元方法和实验,验证该模型的有效性.