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关键词： 变频器  

ISBN: (纸本)9787113306298

摘要： 本书采用全图解的方式，由浅入深地讲解了变频器电路芯片级维修的方法和技能；在具体讲解中，本书秉承理论实践相结合的原则，结合大量案例详细讲解了变频器维修方法，总结了变频器电源电路板、主控制板等主要电路的维修经验。

摘要： Multilevel inverter technology is the best preferred choice of high and medium power industrial control applications and its reliability is often lowered by the solid state switches such as IGBT/MOSFET. Timely monitoring and accurate identification of faulty switches is always a challenging area. Numerous measures using current measurement have been recommended to identify and localize any fault in switching devices of inverters. In view of the complications of load current addressed fault finding practices, this work focuses on voltage features of inverter which is independent of load variations. Random forest algorithm is a dominant machine learning process useful in the alignment of large data base and it is considered in this work for identification of faulty switches of multi-level inverter. Results show that random forest algorithm can be used for finding the faulty switches of multi-level inverter in an effective manner.

关键词： IGBT module   Junction temperature   Stochastic PWM   Temperature model  

摘要： The insulated gate bipolar transistor (IGBT) module is a core component of high-power electronic device systems. Since the junction temperature of an IGBT module increases with operation, the junction temperature of the IGBT module is the main cause of failure, which seriously affects the safe and stable operation of systems. To restrain the junction temperature and to improve the reliability of IGBT modules during operation, a new stochastic pulse width modulation (PWM) strategy is proposed. It is deduced that this method can do a good job of restraining the junction temperature of IGBT modules. The effectiveness of this method is verified on an experimental platform of a permanent magnet synchronous motor system. Experimental results show that the stochastic PWM has a good inhibitory effect on the junction temperature of IGBT modules in the same cycle, and that the difference of the most significant inhibition effect is about 3.27 K. The proposed stochastic PWM has practical engineering significance in terms of restraining the junction temperature of IGBT modules.

关键词： DBC segmentation   Deep learning   Online learning   X-ray imaging   Computed laminography  

摘要： Insulated gate bipolar transistor (IGBT) is a power semiconductor module .Voids may arise in its solder process when a contaminant or gas is absorbed into the solder joint. They heavily influence the heat exchange efficiency of IGBT, so void inspection is very important. The segmentation of solder region is a crucial step for automated defect detection of IGBT based on x-ray computed laminography (CL) system. In recent years, deep learning has made remarkable process in semantic segmentation and has been used for the segmentation of solder joint between the direct bonded copper (DBC) substrate and baseplate, which has been proved to be accurate and efficient. However, deep learning architectures exhibit a critical drop of performance due to catastrophic forgetting when new IGBT samples encountered. Hence, this paper proposes to use online learning techniques to continuously improve the learned model by feeding new IGBT samples without losing previously learned knowledge. Acknowledges the inherent limitation of deep learning models, such as catastrophic forgetting, which can hinder performance when encountering new IGBT *** the use of online learning techniques as a solution to continuously improve the model by incorporating new IGBT samples without forgetting previously learned *** to enhance model robustness and adaptability over time, ensuring consistent and accurate defect detection in IGBT soldering processes.

关键词： 水下无人航行器   X型舵   控制分配   二次规划   容错控制   OSQP  

摘要： 针对中高速水下无人航行器(AUV)提高容错控制能力、兼顾机动性与控制精度等需求,提出一种“非对称X型艉舵+小水平艏舵”的AUV舵布局策略并研究与之相适应的高效控制分配方法。本文提出的舵布局策略通过大小舵配合,在力矩需求较小时优先使用小舵以提高控制精度,力矩需求较大时大小舵协作以满足机动性需求。建立了适用于该布局策略的控制分配模型并转化为二次规划问题,采用两阶段法求解该模型,依次为确定大舵使能阶段和求解小舵需求阶段。所形成的二次规划问题采用OSQP求解方法,首先通过快速迭代得到中低精度解再进行一次解精确处理,兼顾求解效率和精度.最后通过机动性与精度、容错控制及不同二次规划方法求解效率对比等三方面仿真验证了研究方法的有效性.

关键词： C2000新型DSP   矢量控制   环路控制  

摘要： 永磁同步电机高效率、高功率密度、良好的转矩性能和易于控制等优点在工业自动化、汽车、航空航天、家用电器等领域发挥着重要作用。然而,在电气传动领域不仅需要精确地控制其运行状态,还需具备复杂的工业通信和人机接口。传统电气传动大多采用比例积分环节进行速度控制,会存在积分器饱和问题,扰动消失后,积分响应变慢;复杂的工业通信和人机接口需要占用大量的芯片资源和芯片IO,导致控制成本居高不下。通过对传统的比例积分器进行改进,引入输出前馈控制,解决由于积分器饱和带来的响应延迟,并通过改进外部通信协议和外部人机交互接口硬件电路,解决了传统传动系统设计只能通过增加芯片数量来解决资源和IO占用问题。改进后的系统可以在单芯片280039C DSP上完成全部功能,由于不存在芯片间通信,通信速率和响应速度都大幅提升,现场使用情况良好。

关键词： 双向全桥DC-DC变换器   双重移相控制   最小回流功率   电流应力   直流微电网  

摘要： 双向全桥DC-DC变换器以其重量轻、高功率密度、能量双向流动等优点成为直流微电网中不可或缺的一部分。但双向全桥DC-DC变换器在传统的单重移相控制下存在回流功率和电流应力等问题,尤其当输入电压和输出电压不匹配时,回流功率和电流应力会显著增加。针对输入电压和输出电压不匹配的情况,该文提出了一种双向全桥DC-DC变换器在双重移相下的最小回流功率控制策略。该控制策略通过对回流功率进行分段优化,得到了变换器在不同传输功率范围下的最优移相角。通过将所提控制策略和传统的双重移相控制进行对比分析,发现该文所提控制策略具有更小的回流功率和电流应力,提升了变换器的效率。最后基于所提控制策略搭建了实验样机,实验结果验证了控制策略的正确性和有效性。

关键词： PLC   变频器   触摸屏   Modbus通信   控制程序  

摘要： 阐述三菱PLC、变频器、触摸屏技术的综合应用,包括Modbus通信协议、通信线的连接、通信的设定、控制程序的设计。在综合应用过程中,系统实现数据联动,根据需要灵活配置各模件数量,满足参数设置和控制要求,通过程序来完成系统的数据收集、模拟量检测等功能。

关键词： 火电厂锅炉   风机变频器   系统改造   自动化控制  

摘要： 结合某火电厂锅炉风机变频器改造项目,介绍风机变频器改造设计方案,探讨变频器电气控制系统、高压变频器逻辑控制系统、电机与风机连接等改造设计措施,并提出自动化控制设计要点。通过科学合理的改造计划,提高锅炉风机运行效率,保证其安全性,确保风机变频改造节能的效果。