Permanent Magnet Temperature Estimation for PMSMs Using Virtual Position-offset Injection

This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is mathematically transforming the machine model to a virtual frame with a position-offset. The virtual frame temperature estimation model is derived to calculate the permanent magnet temperature(PMT) directly from the measurements with computation efficiency. The estimation model involves a combined inductance term, which can simplify the establishment of saturation compensation model with less measurements. Moreover, resistance and inverter distorted terms are cancelled in the estimation model, which can improve the robustness to the winding temperature rise and inverter distortion. The proposed approach can achieve simplified computation in temperature estimation and reduced memory usage in saturation compensation. While existing model-based approaches could be affected by either the need of resistance and inverter information or complex saturation compensation. Experiments are conducted on the test machine to verify the proposed approach under various operating conditions.

Therapeutic efficacy of methylprednisolone sodium succinate via diverse administration routes for mid-to high-frequency sudden sensorineural hearing loss

BACKGROUND Sudden sensorineural hearing loss(SSNHL),characterized by a rapid and unexplained loss of hearing,particularly at moderate to high frequencies,presents a significant clinical challenge.The therapeutic use of methylprednisolone sodium succinate(MPSS)via different administration routes,in combination with conventional medications,remains a topic of interest.AIM To compare the therapeutic efficacy of MPSS administered via different routes in combination with conventional drugs for the treatment of mid-to high-frequency SSNHL.METHODS The medical records of 109 patients with mid-to high-frequency SSNHL were analyzed.The patients were divided into three groups based on the route of administration:Group A[intratympanic(IT)injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection],Group B(intravenous injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection),and Group C(single IT injection of MPSS).The intervention effects were compared and analyzed.RESULTS The posttreatment auditory thresholds in Group A(21.23±3.34)were significantly lower than those in Groups B(28.52±3.36)and C(30.23±4.21;P<0.05).Group A also exhibited a significantly greater speech recognition rate(92.23±5.34)than Groups B and C.The disappearance time of tinnitus,time to hearing recovery,and disappearance time of vertigo in Group A were significantly shorter than those in Groups B and C(P<0.05).The total effective rate in Group A(97.56%)was significantly greater than that in Groups B and C(77.14%and 78.79%,χ^(2)=7.898,P=0.019).Moreover,the incidence of adverse reactions in Groups A and C was significantly lower than that in Group B(4.88%,3.03%vs 2.57%,χ^(2)=11.443,P=0.003),and the recurrence rate in Group A was significantly lower than that in Groups B and C(2.44%vs 20.00%vs 21.21%,χ^(2)=7.120,P=0.028).CONCLUSION IT injection of MPSS combined with conventional treatment demonstrates superior efficacy and safety compared to systemic administration via intravenous infusion and a single IT injection of MPSS.This approach effectively improves patients'hearing and reduces the risk of disease recurrence.

Development of a plastic injection molding training system using Petri nets and virtual reality

In this study, Virtual Reality (VR)-based plastic injection molding training system (VPIMTS), which can be modeled as an integrated system with a task planning module, an intelligent instruction module, a simulation module, and virtual envi-ronment (VE) module, was developed. Presented in this paper are an architecture of VPIMTS, a practical knowledge modelling approach for modelling the training scenarios of the system by using Petri nets formalism and key techniques (FEM, injection molding procedure modelling) which have been developed independently. The utilization of the Petri net model realized the environment where the trainee can behave freely, and also made it possible to equip the system with the function of showing the next action of the trainee whenever he wants. The overall system is a powerful approach for highly improving the trainee’s comprehension and injection molding study-efficiency by building digital, intelligent, knowledgeable, and visual aids.

混合现实技术在椎体成形治疗中的应用

背景:如何提高椎体成形术中穿刺的精准性、减少手术损伤、提高手术效率是目前椎体成形治疗技术探索和改进的焦点之一。目的:探讨混合现实临床设计方案在脊柱骨折经皮椎体成形过程中应用的临床意义。方法:选择2023年6月大连市第二人民医院收治的2例脊柱骨质疏松性腰椎椎体压缩骨折患者,患者术前行腰椎128排CT扫描并获得医学数字成像和通信原始数据,Visual Volume软件构建脊柱压缩性骨折三维网络模型。运用全息影像眼镜将三维网络模型影像精确映射于真实世界,协助术者完成术前模拟、术前病情及治疗方案阐述,以及术中引导穿刺及骨水泥注射。结果与结论:①在混合现实临床设计方案辅助下可实现经皮椎体成形治疗的精准穿刺,术后影像学检查示骨水泥充填良好、无明显渗漏,术后患者症状缓解良好,术后当天即可下地活动;②提示混合现实临床设计方案有助于术者术前进行完善的手术设计、提高与患者及家属的沟通效率;术中协助精准穿刺、缩短手术时间、减少副损伤,是一种新的有效的临床诊疗模式,在脊柱外科微创化、精准化、个性化的治疗中具有发展潜力。

基于虚拟方波注入的五相永磁同步电机开路故障下直接转矩控制

在传统直接转矩控制(DTC)中,参考磁链往往是一个固定值,这将导致五相永磁同步电机(PMSM)在正常及容错情况下运行时效率不高。为解决该问题,该文提出一种基于虚拟方波注入的DTC(VSWI-DTC)策略。首先,建立五相PMSM在正常和开路故障情况下的数学模型,在同步旋转坐标系中推导出恒定转矩下电流幅值与定子磁链幅值的关系。其次,设计最优定子磁链探测器。通过向定子磁链幅值中注入虚拟方波信号,根据电流幅值的变化情况补偿定子磁链幅值,在线探寻最优定子磁链幅值。最后,与无差拍DTC相结合,实现电机高效率DTC运行。实验结果表明,所提策略不但能保持DTC良好的动态性能,抑制开路故障引起的转矩脉动,而且提高了电机在正常和开路故障情况下的效率。

Location of Asymmetric Ground Fault Using Virtual Injected Current Ratio and Two-stage Recovery Strategy in Distribution Networks

Sparse measurements challenge fault location in distribution networks.This paper proposes a method for asymmetric ground fault location in distribution networks with limited measurements.A virtual injected current vector is formulated to estimate the fault line,which can be reconstructed from voltage sags measured at a few buses using compressive sensing(CS).The relationship between the virtual injected current ratio(VICR)and fault position is deduced from circuit analysis to pinpoint the fault.Furthermore,a two-stage recovery strategy is proposed for improving reconstruction accuracy of the current vector,where two different sensing matrixes are utilized to improve the incoherence.The proposed method is validated in IEEE 34 node test feeder.Simulation results show asymmetric ground fault type,resistance,fault position and access of distributed generators(DGs)do not significantly influence performance of our method.In addition,it works effectively under various scenarios of noisy measurement and line parameter error.Validations on 134 node test feeders prove the proposed method is also suitable for systems with more complex structure.

考虑逆变器非理想特性的永磁电机MTPA控制策略

最大转矩电流比(MTPA)控制可以降低铜损,进而有效提高电机效率,适用于空调永磁压缩机系统,但受逆变器非理想特性的影响,最优电流矢量角追踪精度存在下降问题。研究逆变器非理想特性对虚拟直流信号注入MTPA方法的负面影响并给出补偿方法。针对控制系统数字延迟问题,根据系统采样时间对电流矢量角追踪过程中的电压信息进行校正;此外,采用基于饱和函数的死区补偿方法,降低逆变器非线性引起的电压误差。实验结果表明,所研究的逆变器非理想特性补偿方法提高了最优电流矢量角追踪的准确性。

内置式永磁同步电机无传感器最小损耗控制

针对内置式永磁同步电动机(IPMSM),提出了一种内置式永磁同步电机无传感器最小损耗控制策略。由于传统转子磁链观测器不易得到初始转子通量,且存在直流偏置问题,通过梯度下降法构造改进非线性观测器,提高转子位置辨识精度。为降低控制系统的能耗,通过虚拟信号注入法构造虚拟功率电流补偿控制器,在线搜索最优调节电流。通过系统仿真结果表明,该策略能快速观测转子位置,相较于i d=0控制与VCCC,在相同工况下,能耗分别降低了4%~24.21%和1.33%~9.15%,有效提高控制系统的能耗优化性能。

Research on performance testing of radio fuse based on virtual separation technology

The conception of virtual separation technology about high low frequency of electronic module was put forward based on the analysis of tactical performance testing of radio fuse.By means of the principle of fuse Doppler signal acquisition and injection,the high low frequency of electronic module was virtually separated,and one of important parameters—burst height of radio fuse is tested precisely.

考虑位置观测误差的永磁同步电机无传感器驱动系统MTPA控制策略

最大转矩电流比(MTPA)控制是提升永磁同步电机无传感器驱动系统效率的重要手段之一。在无传感器驱动系统中,传统计算法根据公式推导最优电流矢量角解析解,无法计及位置观测误差变化的特性,而注入虚拟信号寻优方法受位置观测误差影响精度降低。为解决该问题,提出一种考虑位置观测误差的MTPA方法。所提方法通过比较上述两种方法在无传感器驱动系统中对最优电流矢量角不同的追踪结果估计位置观测误差,利用估计的位置误差对电机数学模型进行校正以实现最优电流矢量角高精度追踪。最后,在2.2kW内置式永磁同步电机实验平台验证了所提方法的有效性。

注塑模具结构认知与拆装虚拟现实系统开发

以虚拟现实技术为基础,利用VR硬件设备,开发注塑模具虚拟拆卸和装配平台,实现了设备学习、结构认知、拆卸和装配等功能。首先,采用3DMAX建立模具模型,对模型颜色、外观进行处理;然后将模型导入到Unity3D里面,按照实际装配顺序添加动画、特效。该系统利用虚拟装配技术,实现注塑模具拆卸和交互等功能,可以解决实际模具有限、不方便重复操作模具等问题。

面向虚拟电厂的协同网络攻击模型及跨空间故障传播机理

电力专网与公用互联网的互动可深度挖掘虚拟电厂的灵活性潜力,然而虚拟电厂在提供灵活性服务时易受到公网侧的网络攻击致使系统出现灵活性缺额,进而影响新型电力系统的运行安全。针对虚拟电厂遭受协同网络攻击,首先根据虚拟电厂的运行机制和通信网络架构,给出了公网侧潜在的网络攻击途径;其次,建立了电动汽车的混合逻辑动态模型来推演其后续时间断面的灵活性调节容量;然后,建立了虚假数据注入和拒绝服务两种典型网络攻击的事件驱动模型,在此基础上提出了基于事件驱动-融合流模型的电网安全状态动态推演方法;最后,对改进的IEEE 30节点系统进行了仿真计算,结果表明所提方法能够刻画跨空间故障的传播路径并量化协同网络攻击对电网的危害,为电网运行人员开展动态风险评估与信息安全防护奠定基础。

基于数字孪生的虚拟仿真系统研究与应用

为解决全实物平台开发环境搭建困难、不便于测试与维护等问题,在研究PowerPC处理器的实时嵌入式开发的基础上,采用数字孪生技术的设计思想,完成了一种拥有故障模拟与注入、协同仿真与模块化编程等功能的超实时虚拟仿真系统;提出了一种全数字仿真系统的设计与实现方法,基于数字孪生技术把硬件主板上的处理器以及外围设备虚拟化,集成到数字模型当中;各模型之间相互协同控制,实现CPU控制外部设备与动力学模型等设备之间的通信,以及数据收发、内存读写、串口输出等行为,最终实现与物理设备相同的功能;另外,采用了虚实结合的方法验证了运行结果的准确性,加快了软件执行效率,便于快速全面的系统开发与测试,从而更好地运用到各个领域当中。

基于云平台的智能化储气系统设计

以地下储气库安全、智能化地注入与天然气智能化采集为目标,设计基于云平台的智能化储气系统。系统的基础设施层在地下储气库注采井中设置天然气传感模块。通过天然气传感模块采集注采井内的天然气浓度、流量、液压等数据。所采集的天然气数据传送至井口安全控制模块。井口安全控制模块利用技术层的比例积分微分(PID)神经网络的智能控制算法,控制地下储气库注采井井口安全阀关断,保障地下储气库的安全生产。智能化储气全过程在系统的业务层完成。业务层结合引擎模块、开发工具模块、支撑模块、管理模块共同合作为云平台用户提供服务。系统通过虚拟机迁移控制方法降低云平台的资源消耗,以提升云平台运算效率。系统测试结果表明,所设计的系统可以智能化地控制地下储气库注采井井口安全阀,保障天然气的良好注入与采集。

基于Web的注塑工艺虚拟仿真实验平台设计

为增强学生对汽车内饰件主要成型方法注塑工艺的感性认识,同时提升高分子材料注塑成型工艺的实验教学效果,教学团队基于“云端”理念,以浏览器为平台、代码为工具,利用互联网技术,设计开发了网页式的注塑工艺虚拟仿真实验平台。开发过程为首先制作视频、动画、文档资料等各类实验素材,然后使用代码编译器编写控制命令代码,最后经过浏览器渲染,完成了Web网站的初步设计。设计开发的注塑工艺虚拟平台包含材料、工艺、设备(模具)三大要素,整合并优化了文档、视频、动画等多媒体资源,并提供教学管理服务以及简单的人机交互操作。经调试、修改并投入试用后,学生普遍认为提升了学习兴趣,教师认为有效促进了“混合式”教学的开展,教学效果较好。本虚拟仿真平台的开发有力助推了课程教学改革。

负载均衡的2D Mesh单节点故障容错路由算法

单故障节点2D Mesh环路故障绕行常常会导致数据传输负载和网络时延增大,针对这一问题,提出一种单节点故障预测无虚通道容错路由算法。该算法首先基于内建自测试机制获取故障节点的坐标信息;然后根据源节点、目标节点和故障节点的相对位置分别采用不同的路由策略进行数据传输,并且数据传输具有无死锁的特性。基于8×8的2D Mesh网络,实验结果表明,相比较可重构路由算法,新算法的饱和注入率提高了39.42%;相比较容错路由算法,新算法的饱和注入率提高了18.92%。在网络负载均衡、减少端到端传输距离和网络时延方面,单节点故障预测无虚通道算法具有可行性。

无变压器非隔离型光伏并网逆变器直流注入控制技术

直流注入是光伏并网发电系统中的一个重要问题。IEEEStd.929-2000规定直流注入必须小于系统额定电流的0.5%。然而,目前关于直流注入问题的相关研究较少。借鉴电容隔离直流的特性,从控制理论角度出发,提出一种基于虚拟电容的并网逆变器直流注入控制策略,通过并网电流前馈至占空比实现虚拟电容,有效地消除了并网电流中可能存在的直流分量。分析此方案的工作原理,设计电流控制和锁相算法,并采用Matlab/Simulink进行仿真研究。在500W实验样机上进行方案可行性分析,实验结果验证了此方案的有效性。

模具机构设计虚拟实验系统研究与开发

分析了注塑模具机构设计原则与要求,给出了脱模机构虚拟实验设计系统的总体结构。应用面向对象的知识表示与现有的模具机构,开发了模具机构虚拟实验系统。实现了注塑模具机构虚拟化实验和结构设计的二维、三维仿真,并总结虚拟试验系统的实际教学效果。

基于CAE的虚拟注射成型系统的研究和开发

研究了虚拟制造技术在注射成型过程中的应用 ,通过建立模架装配模型和模架的运动描述 ,开发出了基于CAE的虚拟注射成型原型系统 ,并将其与注射成型CAE系统HsCAE3D集成 ,取得了良好的效果。

静脉虚拟注射系统在护理实训教学中的应用

目的探讨静脉虚拟注射系统应用于护理实训教学中的优势与不足。方法选取2014级护理专科学生30名,采用传统教学与静脉虚拟注射系统相结合授课。课后采用问卷调查学生对静脉虚拟注射系统的评价,并进行随堂测验及操作考试。结果学生认为静脉虚拟注射系统丰富学生临床知识(30/30)、利于学生自学(27/30)、节省耗材(27/30)、提高学生学习兴趣(23/30)。但对系统的操作完整性(5/30)、手部穿刺模块(5/30)表示不满意。结论静脉虚拟注射系统在丰富学生临床知识、提高学生自学能力及节省实验耗材等诸多方面具有一定优势,是一个良好的教学辅助手段。