Due to insufficient current tracking capability, traditional control methods generate significant torque and levitation force ripples, which are detrimental to system stability. This article proposes a novel predictive current control (PCC) algorithm by integrating the structural characteristics of a 12/8 bearingless switched reluctance motor with wider rotor teeth (BSRMWR). Compared to conventional predictive current methods, the proposed algorithm eliminates the need for prestored magnetic flux or inductance tables, significantly simplifying implementation. Furthermore, to minimize copper loss, the reference current criteria are optimized using a Lagrange function. A novel force sharing function (FSF) is also designed to compensate for computational delays. Finally, simulation and experimental results validate the effectiveness and feasibility of the proposed method.

In the high-power or high-speed permanent magnet synchronous motor drive system, the complex vector current regulator in the motor parameter mismatch and low carrier ratio conditions have shown excellent control performance, the traditional design of the complex vector current regulator in order to simplify the design process does not take into account the effect of the delay of the digital control system, resulting in the preset current loop bandwidth and the actual current loop bandwidth is distorted, relying on the preset current loop bandwidth of the design of the current regulator parameters can not make the current control effect as expected. The current regulator parameters designed based on the preset current loop bandwidth cannot make the current control effect reach the expectation. To this end, under the premise of fully considering the complex vector current regulator, the motor and the digital delay link, the Euler formula is used to expand the delay link in the frequency domain, and the current loop closed-loop transfer function is reconstructed by relying on the two important parameters of the current loop bandwidth and digital delay, and the algebraic relationship between the controller parameters and the current loop bandwidth and the digital delay is derived through the closed-loop transfer function, so as to propose an algebraic relationship between the controller parameters and the digital delay, and thus the design precision of the complex vector current regulator can be improved by the current loop bandwidth. Based on this, a complex vector current regulator parameter tuning method that can improve the design accuracy of the current loop bandwidth is proposed. The effectiveness of the proposed scheme is verified by both simulation and experiment.

Direct torque control, direct instantaneous torque control (DITC), and direct force control strategies have been well applied in bearingless switched reluctance motors (BSRMs), which can obtain good torque and levitation characteristics by hysteresis-loop control method. However, hysteresis-loop control method can result in torque ripple due to loop width, which increases the rms currents. On the other hand, commutation at the maximum inductance can result in torque spikes, which can deteriorate the commutation process. Therefore, this article proposes an improved control strategy to further reduce torque spikes and ripple for BSRMs. In the proposed strategy, the torque sharing function is investigated to make torque transition smoother. Moreover, model predictive control (MPC) method is employed to replace the hysteresis loop, which reduces the torque ripple and reduces the rms currents. At the same time, torque—ampere ratio can be improved as well.

A direct displacement control (DDC) strategy was proposed for bearingless switched reluctance motors (BSRMs) to simplify the torque and displacement control. However, it generates large torque ripple, leading to increased copper loss and noise. Another strategy named direct instantaneous torque control (DITC) and direct force control (DFC), can reduce the torque and levitation force ripples by hysteresis-loop method, which makes the output torque become smoother, yet the disadvantage is greatly increased calculation burden and slow displacement response. Therefore, an improved DDC strategy is proposed to reduce torque ripples and improve the displacement response in this paper. For the torque control, the torque hysteresisloop method is adopted, significantly reducing torque ripples in the proposed DDC method. Moreover, a small-signal model for BSRMs is established to analyze the stability of proposed strategy, and then regulator parameters can be determined accordingly. Experimental results show that the torque ripple and winding currents can be reduced by 41.7% and 44.4%, respectively, compared to DDC strategy. Simultaneously, the adjusting time of displacement is reduced by 61.8% compared with using DITC and DFC strategy during a sudden increase of radial load.

Abstract In traditional magnetic bearing motors, the magnetic bearing and the motor are usually driven and controlled separately, resulting in higher controller costs and limiting further expansion of their applications. The author presents a four‐degree‐of‐freedom (4DOF) magnetic bearing switched reluctance motor (MBSRM), consisting of two 8‐pole active radial magnetic bearings (RMBs) and two two‐phase 4/2‐pole switched reluctance motors (SRMs), driven simultaneously by a set of asymmetrical power converters together. Firstly, the structure, winding configuration and co‐excitation working principles of the 4DOF‐MBSRM system are described in detail. Then the radial force formula for an 8‐pole RMB and the torque mathematical model for a 4/2‐pole SRM are briefly derived based on equivalent magnetic circuits, respectively. Furthermore, a co‐excitation control strategy for the 4DOF MBSRM is developed wherein an instantaneous radial force is used to control its rotor shaft levitation, an instantaneous torque is employed for rotational control at low and medium speeds, and an average torque is used for high speed operation. Finally, the good performance of the co‐excitation control for the proposed 4DOF‐MBSRM is proved by simulation analysis.

In the traditional control scheme of a 12/8-pole bearingless switched reluctance motor (BSRM), radial force and torque are usually controlled as a compromise due to the conflict between their effective output areas. Additionally, each phase requires individual power circuits and is excited in turn to produce a continuous levitation force, resulting in high power device requirements and high controller costs. This paper discusses a 12/8-pole single-winding hybrid-rotor bearingless switched reluctance motor (HBSRM) with a hybrid rotor consisting of cylindrical and salient-pole lamination segments. The asymmetric rotor of the HBSRM slightly increases the complexity of its structure and magnetic circuit, but makes it possible to generate the desired radial force at any rotor angular position. A control scheme for the HBSRM is developed to utilize the independent excitation of the four windings in one phase to generate the desired levitation force at any rotor angular position, and it requires only half the number of power circuits used in the conventional control scheme of a 12/8-pole single-winding BSRM. Different from the average torque chosen to be controlled in traditional methods, this scheme directly regulates the instantaneous total torque produced by all excited phases together and presents a current algorithm to optimize the torque contribution of each phase so as to reduce torque pulsation, and the improved performance of this bearingless motor is finally validated by simulation analysis.

The coupling between torque and radial force, and between the two radial forces is detrimental to the efficient control and performance improvement of the bearingless switched reluctance motor (BSRM). In the article, an 18/16-pole permanent magnet (PM) biased BSRM with radial force windings driven by a three-phase full-bridge inverter is presented. To solve the coupling between two radial forces in this proposed BSRM, three of its derived decoupled topologies have been developed, and the decoupled characteristics of these structures are proved by the radial force mathematical model and finite element analysis. Further, based on the space vector pulse width modulation (SVPWM) technique for three-phase full-bridge inverters, a one-cycle digital control scheme for the radial force control applicable to four types of BSRMs has been developed. Finally, a BSRM is prototyped and tested for experimental validation of radial levitation.

This paper mainly describes a segmented PWM control method to minimize commutation torque ripple to achieve smooth operation of the motor at high and low speeds. The reasons for commutation torque ripple generated by brushless DC motors in three-phase six-state and two-phase conduction mode were analyzed. and a commutation torque ripple suppression strategy under ON-PWM modulation is proposed. This strategy considers the influence of the change of back EMF on the torque ripple during the commutation process, and further improves the compensation effect of commutation torque ripple, so as to realize the low torque ripple operation of the motor at low speed and high speed. By establishing a system simulation model in Matlab/Simulink environment, it is confirmed that the new control strategy can effectively reduce the commutation torque ripple, and verify the effectiveness and theoretical correctness of the control method.

AbstractA backstepping controller based on a non‐linear disturbance observer (NDOB) was created to enhance the dynamic performance and reliability of three‐degree‐of‐freedom hybrid magnetic bearings. After the structure of three‐degree‐of‐freedom hybrid magnetic bearings is introduced, the mathematical model is established, and the equation of the state is derived by the equivalent magnetic circuit technique. Based on the mathematical model, non‐linear disturbance observer (NDOB) is designed and is used to predict the system disturbance, and the backstepping control algorithm is compensated. To verify the effectiveness of the proposed controller, the backstepping controller, proportion integration differentiation controller, and backstepping controller based on a NDOB were compared by simulation and experiment. Results show that the backstepping controller based on a NDOB has better dynamic performance and robustness.

脉振的径向电磁力作为激励源作用于12/8极单绕组宽转子齿无轴承开关磁阻电机(Bearingless switched reluctance motor with wider rotor teeth,BSRMWR)的定子齿面并传送至定子轭部及机壳,会引发较大的振动噪声,阻碍其推广应用.针对这一问题,本文从本体结构的角度入手对电机壳体进行优化改进.采用三维多物理场有限元模型,建立了BSRMWR电磁?结构?振动?声场耦合模型.通过对BSRMWR电磁场进行瞬态分析,得到径向电磁力.将模态应变能方法应用于BSRMWR的壳体得到电机外壳结构有较大的应变能,说明电机壳体结构的薄弱.基于此,通过形貌优化的方法对电机的壳体结构进行优化.结果表明,采用形貌优化后机壳结构的BSRMWR,其振动和噪声均有显著改善.

冷链药品的配送量在互联网+医药和新冠疫情双重推动下显著增长,但目前冷链药品的配送存在着"断链"、温控不到位、信息系统不全面、配送人员温度控制意识不强等问题,同时医药改革带来了药品配送的新需求和新发展.随着当前物联网、RFID等新技术的发展和应用以及药店新功能的出现,将这些新技术应用到药品冷链配送的全程中,并将药品冷链配送最后一公里进行延伸,可更好地解决药品冷链配送存在的问题.

通过对GDYT公司工程变更原因进行分析,总结出存在的问题,通过对工程变更4要素的分析和优化,提出解决的建议,从而达到降低变更成本、提高变更效率和减少变更错误的目的.分析了工程变更中变更流程、人员组织、数据管理以及IT系统等要素的相互关系.

To achieve levitation in active magnetic bearing (AMB) systems, levitation coils must be driven by a switch power amplifier (SPA). Therefore, SPA performance is important to stable levitation. In previous studies, five-phase six-leg (5P6L) SPA topology was proposed to reduce hardware costs. However, current tracking performance degrades due to the coupling problem of the five-phase current and freewheeling loss. Then, the rotor may deviate markedly from the balance position, affecting rotor stability. The keys to solving these problems lie in the duty cycle control of the common leg and the compensation of freewheeling loss. This article proposes an improved one-cycle control (OCC) algorithm in which the duty cycle of the common leg is optimized by finite control set model predictive control (FCS-MPC), and the freewheeling loss is compensated for by a high-precision mathematical model. In addition, the parameter uncertainty of the FCS-MPC model is analyzed, and the convergence of the optimization algorithm is investigated. Simulations and experiments show that the proposed algorithm is effective, and the high dynamic response and low steady-state error performance of SPA are achieved.

车用电机体积小,功率密度高,导致其温升较高,而温升直接影响电机的使用寿命和运行可靠性,因此热分析成为电机设计的关键环节.以一台额定功率为60 kW的四相16/12开关磁阻电机为研究对象,基于集总参数热网络法(Lumped Parameter Thermal Network,LPTN),建立电机集中参数热模型,分析电机稳态温度分布和瞬态温升,对机壳水冷和喷淋冷却的效果进行分析,并得出在低速和高速运行下限制电机连续运行的因素.在此基础之上,对冷却水道数目和冷却液流量对电机温升的影响进行分析,为相同冷却条件和功率等级的开关磁阻电机选择合理的冷却水道数目和冷却液流量提供参考依据.

物流管理专业认识实习是物流实践课程的重要组成部分,关系到学生对物流专业的整体认知以及后续专业课程学习的热情,因此加强对物流管理专业认识实习的研究具有较为重要的意义.首先总结认识实习过程中存在的问题,进而提出建立"参、训、讲、研"的教学体系、搭建双轨制的教学平台、打造"双师"的教学指导模式.同时坚持以学生为中心,加强学生自研能力的培养,并增加过程考核的评价模式,为物流管理专业认识实习的有效开展提供借鉴.

A bearingless switched reluctance motor (BSRM) has the combined characteristics of a switched reluctance motor (SRM) and a magnetic bearing. The hybrid-rotor BSRM (HBSRM) discussed in the paper has a twelve-pole stator and an eight-pole hybrid rotor, which is composed of a cylindrical rotor and a salient-pole rotor. Although the asymmetry of the hybrid rotor makes the structure and magnetic field of the HBSRM more complex, it can always produce a significant amount of magnetic pulling force to levitate a rotor shaft at all the rotor angular positions of each phase, which is not available in a traditional BSRM. The classical mathematical model for a conventional BSRM is valid only when its rotor rotates from the start of the overlap position to the aligned position, and the radial force and torque derived from this model are discontinuous at the aligned positon, which is harmful to the motor’s stable operation. In this paper, a full-period mathematical model on the assumption that the gap permeance is cut apart by straight lines or improved elliptical lines for a 12/8-pole HBSRM is provided. On the basis of this mathematical model, the continuity of the radial force and torque at all the rotor angular positions can be guaranteed, and the fine characteristics of this mathematical model have been verified by simulations.

针对无轴承开关磁阻电机在换相时励磁电流建立速度过慢,本文提出了一种结构简单的升压型功率变换器,电机在换相时,通过利用绕组退磁能量来为后一相绕组迅速建立励磁电流,在保证电机稳定悬浮的基础上实现电机换相时的低转矩脉动运行.分析了该功率变换器的拓扑结构以及工作状态,在此基础上,构建了基于该新型升压功率变换器的12/8极单绕组宽转子齿无轴承开关磁阻电机驱动系统,通过Matlab/Simulink系统仿真,验证了该功率变换器的可行性和有效性.

针对混合径向磁轴承用的位移传感器容易发生故障可靠性不高的问题,依据冗余位移传感器检测思路,采用坐标变换矩阵技术,提出一种位移传感器的故障识别与容错控制方法.通过将位移传感器非对称安装在混合径向磁轴承的外围,根据位移传感器的故障状态选取不同的坐标变换矩阵,实现转子在水平和竖直两个自由度上的位移检测.传感器位置的非对称安装降低了由于传感器数量增加而引起的电磁干扰影响并且提高了容错能力,对冗余位移传感器最优安装位置的分析提高了传感器可检测范围,能够实现4种传感器故障状态的容错控制.通过在两对极混合径向磁轴承系统中的仿真验证,表明所述方法能够有效、快速实现位移传感器的容错控制,具有结构简单、容错能力高和适用范围广的优点.

The stator and rotor of the bearingless switched reluctance motor are both double salient pole structures, when the traditional current chopping control method is used, the torque and levitation force of the motor will have large fluctuations. To solve this problem, this paper studies a direct instantaneous torque control and direct levitation force control (DITC&DFC) method suitable for single-winding bearingless switched reluctance motors. This method takes the instantaneous torque and the instantaneous levitation force of the motor as the directly controlled object, eliminates the current loop, and simplifies the control algorithm while suppressing the fluctuation of the motor torque and levitation force. A 12/8-pole singlewinding bearingless switched reluctance motor with wide rotor teeth drive system is constructed, the Matlab/Simulink system simulation verifies the effectiveness and feasibility of the method.

根据专业人才培养的定位和要求,立足智能电网信息安全学科,针对智能电网中可能存在的安全威胁,从教学的角度出发,立足南京邮电大学多年打造的智能微电网实验平台,从基础性演示和验证实验、综合性设计实验和创新研发性实验三个层面设计了智能电网信息安全的实践教学环节的内容,对智能电网中遇到的拒绝服务、篡改(欺骗)攻击、重放攻击、网络协同攻击等安全威胁,在实验平台上进行实验,并根据信息物理融合系统模型,从理论的角度分析实验结果,验证和评价安全防御策略的有效性,并设计有针对性的安全防御策略.