Fuzzy Based Interleaved Step-up Converter for Electric Vehicle

This work focuses on the fuzzy controller for the proposed three-phase interleaved Step-up converter(ISC).The fuzzy controller for the proposed ISC converters for electric vehicles has been discussed in detail.The proposed ISC direct current(DC-DC)converter could also be used in automobiles,satellites,industries,and propulsion.To enhance voltage gain,the proposed ISC Converter combines boost converter and interleaved converter(IC).This design also reduces the number of switches.As a result,ISC converter switching losses are reduced.The proposed ISC Converter topology can produce a 143 V output voltage and 1 kW of power.Due to the high voltage gain of this converter design,it is suitable for medium and high-power systems.The proposed ISC Converter topology is simulated in MATLAB/Simulink.The simulated output displays a high output voltage.But the output voltage contains maximum ripples.Fuzzy proposes an ISC Converter which makes closed loop responsiveness and reduces the output voltage ripple.The proposed ISC converter has the lowest ripple output voltage,which is less than 2%,because the duty cycle is regulated using the fuzzy logic controller.It offers high voltage gain,minimal ripple,and low switching loss.The performance of the proposed converter is compared to that of the fuzzy and Pro-portional Integral(PI)controllers implemented in MATLAB.

半钢子午线轮胎两段一次法成型机的研制

半钢轮胎成型中两次法和一次法两种工艺一直并行,近年来一次法设备发展迅速,导致两次法工艺逐步边缘化,甚至两次法擅长的AT、MT轻卡系列轮胎都没有对应的设备支撑。本文旨在提供一种高智能化、高效率的两段成型方法和成型设备。

一种低输入电压、低功率Step-up DC-DC变换器的设计

文章提出一种Step-up DC-DC的变换器的设计方法,效率高达70%,输入电压范围低至500 mV,最小起动电压能够达到300 mV。

Mortality and morbidity in necrotizing pancreatitis managed on principles of step-up approach:7 years experience from a single surgical unit

AIM To determine percentage of patients of necrotizing pancreatitis(NP) requiring intervention and the types of interventions performed. Outcomes of patients of step up necrosectomy to those of direct necrosectomy were compared. Operative mortality, overall mortality, morbidity and overall length of stay were determined. METHODS After institutional ethics committee clearance and waiver of consent, records of patients of pancreatitis were reviewed. After excluding patients as per criteria, epidemiologic and clinical data of patients of NP was noted. Treatment protocol was reviewed. Data of patients in whom stepup approach was used was compared to those in whom it was not used. RESULTS A total of 41 interventions were required in 39% patients. About 60% interventions targeted the pancreatic necrosis while the rest were required to deal with the complications of the necrosis. Image guided percutaneous catheter drainage was done in 9 patients for infected necrosis all of whom required further necrosectomy and in 3 patients with sterile necrosis. Direct retroperitoneal or anterior necrosectomy was performed in 15 patients. The average time to first intervention was 19.6 d in the non step-up group(range 11-36) vs 18.22 d in the Step-up group(range 13-25). The average hospital stay in non step-up group was 33.3 d vs 38 d in step up group. The mortality in the step-up group was 0%(0/9) vs 13%(2/15) in the non step up group. Overall mortality was 10.3% while post-operative mortality was 8.3%. Average hospital stay was 22.25 d.CONCLUSION Early conservative management plays an important role in management of NP. In patients who require intervention, the approach used and the timing of intervention should be based upon the clinical condition and local expertise available. Delaying intervention and use of minimal invasive means when intervention is necessary is desirable. The step-up approach should be used whenever possible. Even when the classical retroperitoneal catheter drainage is not feasible, there should be an attempt to follow principles of step-up technique to buy time. The outcome of patients in the step-up group compared to the non stepup group is comparable in our series. Interventions for bowel diversion, bypass and hemorrhage control should be done at the appropriate times.

One-step laparoscopic pancreatic necrosectomy verse surgical step-up approach for infected pancreatic necrosis:a case-control study

BACKGROUND:The surgical step-up approach often requires multiple debridements and might not be suitable for infected pancreatic necrosis(IPN)patients with various abscesses or no safe route for percutaneous catheter drainage(PCD).This case-control study aimed to investigate the safety and effectiveness of one-step laparoscopic pancreatic necrosectomy(LPN)in treating IPN.METHODS:This case-control study included IPN patients undergoing one-step LPN or surgical step-up in our center from January 2015 to December 2020.The short-term and long-term complications after surgery,length of hospital stay,and postoperative ICU stays in both groups were analyzed.Univariate and multivariate logistic regression analyses were performed to explore the risk factors of major complications or death.RESULTS:A total of 53 IPN patients underwent one-step LPN and 37 IPN patients underwent surgical step-up approach in this study.There was no significant difference in the incidence of death,major complications,new-onset diabetes,or new-onset pancreatic exocrine insufficiency between the two groups.However,the length of hospital stay in the one-step LPN group was significantly shorter than that in the surgical step-up group.Univariate regression analysis showed that the surgical approach(one-step/step-up)was not the risk factor for major complications or death.Multivariate logistic regression analysis indicated that computed tomography(CT)severity index,American Society of Anesthesiologists(ASA)class IV,and white blood cell(WBC)were the significant risk factors for major complications or death.CONCLUSION:One-step LPN is as safe and effective as the surgical step-up approach for treating IPN patients,and reduces total hospital stay.

Controversies in the treatment of Crohn’s disease: The case for an accelerated step-up treatment approach

The ideal treatment strategy for Crohn’s disease (CD) remains uncertain, as does the optimal endpoint of therapy. Top-down versus step-up describes two different approaches: early use of immunomodulators and biological agents in the former versus initial treatment with steroids in the latter, with escalation to immunomodulators or biological drugs in patients proven to be steroid refractory or steroid dependent. Top-down therapy has been associated with higher rates of mucosal healing. If mucosal healing proves to be associated with better long-term outcomes, such as a decreased need for hospitalization and surgery, top-down therapy may be the better approach for many patients. The main concern with the top-down approach is the toxicity of the immunomodulators and biological agents, which have been linked with infectious complications as well as an increased risk of lymphoma. It is unlikely that one strategy will be best for all patients given the underlying heterogeneity of CD presentation and severity. Ultimately, we must weigh the safety and efficacy of the therapies with the risks of the disease itself. Unfortunately our ability to risk stratify patients at diagnosis remains rudimentary. The purpose of this paper is to review the data that supports or refutes the differing treatment paradigms in CD, and to provide a rationale for an approach, termed the "accelerated step-up" approach, which attempts to balance the risks and benefits of our currently available therapies with the risk of disease related complications as we understand them in 2008.

Step-up approach in emphysematous hepatitis: A case report

BACKGROUND Emphysematous hepatitis(EH)is a rare,rapidly progressive fulminant gasforming infection of the liver parenchyma.It is often fatal and mostly affects diabetes patients.CASE SUMMARY We report a case of EH successfully managed by a step-up approach consisting of aggressive hemodynamic support,intravenous antibiotics,and percutaneous drainage,ultimately followed by laparoscopic deroofing.Of 11 documented cases worldwide,only 1 of the patients survived,treated by urgent laparotomy and surgical debridement.CONCLUSION EH is a life-threatening infection.Its high mortality rate makes timely diagnosis essential,in order to navigate treatment accordingly.

Analysis and Design of Single Switch Hybrid Step-Up Converter

A Single Switch Hybrid Step-up Converter with high voltage gain, which is suitable for renewable energy system, is proposed in this paper. The proposed converter consists of one switched diode-inductor cell and a capacitor. While switching, both are charged in parallel from the input source and discharged in series to the output. In order to obtain extra voltage gain at lower duty cycle, the voltage multiplier cell is integrated with the proposed converter. The main advantages of the converter are high voltage gain, reduced voltage stress, simple structure and low output voltage ripples. The operating principle and steady state theoretical analysis are presented. A 250 W prototype converter is implemented with 12 V input and 120 V output to verify the design and analysis of this converter and it has an efficiency of over 90% in all operations.

渣油加氢装置开停工升降压方案优化

4.0 Mt·a^(-1)渣油加氢装置是云南石化加工高硫劣质原油的核心装置,决定了企业加工原油的品种、数量和效益。装置每次开停工,泄压量较大,造成大量火炬排放,浪费氢气资源,引发火炬燃烧排放风险。从膜分离系统原理、运行参数入手,对一、二系列停开工过程升降压方案进行阶段优化,通过排废氢至膜分离系统和排放高压火炬同时进行,一方面提高开停工升降压效率,提高氢气回收率约45%;另一方面减少排放火炬和回收压力,避免火炬燃烧,降低装置开停工过程对全厂氢气管网、火炬回收气柜系统的影响。

高速公路隧道S-Ⅲ级围岩上下台阶法开挖施工技术研究

文中研究了高速公路隧道S-Ⅲ级围岩上下台阶法开挖施工技术,采用C32混凝土喷护岩石,通过小管棚预注浆加固锁口段岩体。通过钻爆作业来保证开挖轮廓正常,安装小导管向四周围岩合理注浆,实现超前加固。采用上下台阶法进行开挖,并采取相应支护措施完成施工。测试结果显示,断面处岩石试件回弹表征值均在45以内;三个测试点的沉降量均在20 mm以下,结果符合预期,该技术能够有效控制围岩变形,施工效果良好。

基于STM32的自动分拣式仓储物流机器人设计

针对目前各大型储物仓库货物数量多、质量大和人工分拣、搬运较为困难导致的一些仓库管理效率低下等弊端,文章设计了一款基于STM32的自动分拣式仓储物流机器人。该机器人采用射频识别(Radio Frequency Identification,RFID)技术自动识别货物信息;通过算法设计自动规划路径运行到相应的货架位置;采用超声波避障技术避开障碍完成智能寻路;利用物联网传感器技术进行称重、利用机械化结构技术进行减震、利用STM32单片机技术上下台阶和升降。该机器人在以上几个模块的协同配合下,能将货物安全、快速、准确地存放于货架上。与传统的人工分拣相比,该机器人使管理效率得到了显著提高,大大降低了人工成本和危险系数,在实现仓储物流的无人化管理方面具有广阔的发展空间与应用前景。

基于开关电容网络的DC-DC变换器

在现有的DC-DC变换器中,Buck、Boost及双向变换器的升降压能力有限,在一定程度上限制了其适用范围。本文提出一种升压型开关电容网络和一种降压型开关电容网络,并在此基础上推演出一系列DC-DC变换器:单级升压变换器、单级降压变换器、双向升降压变换器、多输入升压变换器和多级降压变换器。给出了这五类变换器拓扑的推演过程,详细分析了其工作原理,并通过仿真研究证明了理论分析的正确性。

一种非隔离双向三端口升降压变换器

提出一种非隔离双向三端口升降压变换器拓扑及其功率控制策略。该变换器由3个双向Buck/Boost开关单元不通过直流母线电容级联组合而成;相对于传统多个变换器通过公共直流母线连接的解决方案,该变换器完全消除了中间母线电容,可减小变换器体积、重量和成本,提高系统可靠性,且任意两个端口之间均为单级升降压变换,大大提高了变换器的变换效率和功率密度。详细分析变换器的工作原理,给出相应的脉宽调制(pulse width modulation,PWM)和功率控制策略,最后通过实验验证理论分析的正确性。

航天器多通道近场无线能量传输系统设计

针对航天领域空间交会对接、航天器配电、在轨服务与维护等领域对无缆化的需求,提出了多通道近场无线能量传输系统,建立了多通道磁耦合近场无线能量传输系统数学模型,分析了影响系统传输效率的重要参数,并对关键参数对系统效率的影响进行了仿真分析。通过线圈高效耦合设计,实现了多通道近场无线能量传输系统的效率最优。所提系统解决了能量的无线传输,并实现多负载接收的问题。通过一台1000 W多通道近场无线能量传输样机进行了实验研究,结果表明,所提多通道近场无线能量传输装置具有传输效率高的特点,解决了航天器无线能量传输的多负载问题。

一种基于CUK变换器的通用型固体激光电源

介绍了一种性能优异的新型固体激光电源。采用新型的变换器结构,使电源具有较强的通用性。给出了原理电路模型,分析了工作原理。实验证明,该电源结构简单、适应范围广、成本较为低廉、工作可靠。

三相升-降压PWM整流器Fuzzy-PI控制算法

针对直流电机控制等应用领域对大范围连续平滑可调直流电压的需求,分析了现有升-降压整流系统的不足,基于三相电压型升-降压PWM整流器的工作原理,按照有效降低开关损耗、控制简单、易于工程实现等原则,用拓展零矢量对传统SVPWM控制策略进行改进,建立了相应的数学模型,进行了相应的数学分析,设计了自适应模糊控制和PI控制相结合的双模控制方案,并通过Matlab7.11环境下的离散化模型仿真,将新控制算法与已有控制算法比较,证明了新控制算法的良好效果。

DC/DC谐振开关电容变换器潜电路发生的一般规律分析

潜电路是由于设计时考虑不周,在正常的电子线路中由分布参数、器件非线性状态等诸多因素构成的潜藏于正常设计通道之外的通路。潜电路的隐蔽性很强,并不是在电子系统每次运行都发生作用,而是在某种特定条件下才形成。本文首先对升压、反相谐振开关电容变换器中存在的潜电路进行分析和验证,并与降压谐振开关电容器中的潜电路进行比较,探讨它们出现潜电路时的异同,由此总结潜电路发生的一般规律。本文同时推导出升压、反相变换器在潜电路发生时的参数关系,为预防谐振开关电容变换器潜电路发生提供设计依据。

一种耦合电感双输入升降压变换器

针对温差发电模块输出电压宽范围变化并要求电流纹波小的特点,提出一种耦合电感双输入升降压变换器。其前端为两个Boost单元并联实现双输入,再级联Buck单元实现升降压;Boost与Buck电感反向耦合,减少了磁心数目,并且磁心直流磁通相互抵消,减小了磁心体积和损耗,大大提高了变换效率和功率密度;提出了相应的控制和调制策略以实现分布式MPPT及宽输入电压范围各种工作模态间的平滑切换。详细分析了变换器工作原理和耦合电感特性,搭建了一台450W实验样机,验证了理论分析的正确性和可实现性。

三相升-降压PWM整流器SVPWM控制策略研究

针对目前电机控制等应用领域常用的升-降压整流系统存在无法直接输出大范围连续平滑可调直流电压等不足,分析了基于三相电压型PWM整流电路与C′uk电路整合的升-降压PWM整流器的工作原理,按照控制简单、易于工程实现、有效降低开关频率等原则,用零矢量拓展概念设计了基于SVPWM控制的新控制策略,建立了相应的数学模型,进行了相应的数学分析,采用变参数PI控制和比例-积分分离算法设计了数字PI控制器,仿真结果与实验分析证明了新控制策略的有效性。

基于多假设检验的新型小波滤波算法

小波阈值滤波是信号处理领域的重要方法,根据信号和白噪声在小波空间上传播的特性,提出了一种基于多假设检验确定小波滤波阈值的新算法。将小波阈值处理过程看作一个多重假设检验过程,FDR(False Discovery Rate)准则的step-up和step-down过程均能控制FDR在给定的显著性水平,综合这两个过程形成了FDR step-up-down过程并应用于确定小波滤波阈值。仿真实验表明,算法能够灵活调整显著性水平的大小来达到滤波后所希望的效果,以信噪比和均方误差作为衡量指标,该方法滤波效果与hearsure方法相当,优于BHFDR及sqtwolog方法。讨论了显著性水平的选取对滤波效果的影响,指出显著性水平的大小与信噪比的改善并非线性关系,提出了合理选取显著性水平的思路。