五电平变频器仿真模型的建立

变频器在工农业、国防等领域做出巨大贡献的同时,也产生了一些显著的负面效应。PWM变频器在应用中会产生共模电压。共模电压在IGBT的高速开关期间会产生高频充放电电流,这个电流通过电机内部的寄生电容产生流入地线的漏电流。漏电流过大将对电源产生电磁干扰;感应的轴电压过高还会使电机轴承过早损坏,从而影响系统运行的可靠性。提出了一种新的五电平变频器模型,与两电平逆变器和被常规的脉宽调制控制的嵌位电压相比,所提出的五电平变频器可以使产生的共模电压从最大值到最小值之间明显的降低,并且不会使交流驱动电机的控制效果下降。     

基于HZMB-CORS的GPS-RTK三维多波束水深测量

介绍基于HZMB-CORS的GPS-RTK三维多波束水深测量的基本原理、外业采集软件QINSy中的关键设置与操作、内业处理软件Caris中的GPS-RTK潮位的导入与计算方法。通过实地水深数据采集试验与传统验潮的多波束水深测量方式进行比对,分析其验潮精度、外符合精度以及内符合精度,指出了GPS-RTK三维多波束水深测量在显著提高作业效率以及降低作业成本的同时,有效提升了多波束测深精度以及测深稳定性。     

一种门座起重机回转自动锚定装置

回转锚定是门座起重机回转机构上、下两部分锁定的安全保护装置.针对港口门座起重机回转锚定装置采用人工方式操作所存在的问题,设计一种安装简单、操作便捷的自动锚定装置.该装置采用销轴方式将回转以上和回转以下机构刚性固定,可提高设备非工作状态下的抗风能力.     

脉冲技术在城轨直流馈线保护中的作用

介绍了城轨直流控制系统短路形式及特点。对城轨用直流断路器各分闸方式的固有动作时间进行对比,论证了脉冲脱扣保护的优势。     

491QE汽油机涡轮增压系统设计及模拟计算

为了提高491QE汽油机的性能,进行了增压系统的开发工作。通过计算确定了增压参数,并在原发动机基础上设计了定压排气管和脉冲转换排气管两种增压系统。利用循环模拟程序计算了491QE汽油机增压以后的性能。结果表明,脉冲转换系统在发动机废气能量的利用方面优于定压系统。     

倒立摆的双闭环解耦切换模糊控制设计与仿真

针对多变量、非线性的倒立摆系统,设计了双闭环解耦切换模糊控制.在该方法中,对双闭环参数耦合实现了解耦,使角度环控制倒立摆的角度,位置环控制倒立摆小车的位置,降低了系统设计的难度和复杂度.最后,用MATLAB语言编写数字仿真程序,对所设计的方案进行数字仿真,仿真结果表明了方案的正确性和有效性.     

铜镍管直流脉冲TIG焊工艺试验与应用

为改善铜镍管焊接时的焊缝成形、提高焊接质量,选择手工直流脉冲钨极惰性气体(Tungsten Inert Gas,TIG)焊并采取无间隙组对进行工艺试验。经相关检测,焊后内外焊缝成形优良,表面无缺陷,X射线探伤满足规范要求。试验结果表明:采用手工直流脉冲TIG焊可有效改善管子内壁焊缝成形、减少焊接缺陷、提升焊接质量;采取无装配间隙的组对方式可提高管子零件的制作精度与工作效率,在实船应用中得到推广并取得较好的效果。     

A line impedance stabilization network for pulse current injection北大核心CSCD

［Objective］Aiming at the deficiency of the existing line impedance stability network (LISN) in the electromagnetic pulse protection capability, a LISN suitable for the pulse current injection (PCI) test of electrical and electronic equipment is proposed. ［Methods］Aiming at the characteristics of high peak value and fast rise of the pulse current in PCI testing, the circuit structure and physical structure of the LISN are improved on the existing basis through PSpice time-domain and frequency-domain simulation combined with engineering design requirements, thereby giving it good nanosecond pulse protection performance and impedance stability at the same time. Pulse current protection performance test and impedance curve test experiments are then designed and carried out.［Results］The experimental results show that the improved LISN can attenuate the injected pulse current by 60 times, while the error of its impedance curve is less than 5% compared with the Type 5 µH LISN in GJB 151B-2013. ［Conclusions］The proposed LISN has good impedance stability and decoupling ability, and can be used in the PCI testing of electrical and electronic equipment in order to protect the power supply and improve the repeatability of testing. © 2023 Chinese Journal of Ship Research. All rights reserved.     

船用交流中压配电开关温升在线监测方法

为更好地监测船用交流中压配电开关的温升情况，对比陆用配电开关的温升在线监测方法，分析各测温方法的船海适用性。针对已有的超温判据，提出考虑测温盲点的新超温判据，该判据对船用电器温升在线监测具有一定的参考意义。     

Numerical method of electromagnetic pulse response of conductor with complex load北大核心CSCD

[Objectives]Electromagnetic pulse can seriously affect and even destroy naval shipborne electronic information systems, weapons, equipment and so on. Due to the complexity of the antenna port load circuit, it is necessary to formulate a numerical method which can easily obtain the antenna load current. [Methods]The induced current of the terminal is obtained on the basis of the finite-difference time-domain (FDTD) and Holland model. According to the Thévenin equivalent circuit, the conductor is equivalent to the voltage source to realize decoupling between the conductor and load end, and the load circuit is solved using Simulink software.[Results]Compared with the traditional terminal model, this method is simple and feasible for high-order circuit processing. The effectiveness of the model is verified using non-linear elements and parallel capacitors and resistors as the load respectively. The results show that the calculation results of this method are consistent with those of the traditional methods. Finally, the antenna of the end-connected protect- or is calculated. The results show that the lead inductance caused by the installation of the protector is an important factor affecting the protection performance.[Conclusions]The method proposed in this paper can greatly reduce the simulation complexity of the coupling current of an antenna with a complex load, giving it useful reference value for the field of ship electromagnetic pulse protection design. © 2023 Editorial Department of Chinese Journal of Ship Research. All Rights Reserved.