Pub Date : 2022-11-15DOI: 10.46904/eea.22.70.4.1108002
Mohammed Messaoud, Kraa Okba, Tegani Ilyes
The disadvantages of fuel cell systems, such as their high cost, lack of reactivity, and inability to collect energy when the fuel cell vehicle is braking, can be overcome by hybridization with storage devices such the battery or the supercapacitors, which is capable of doing so. The energy management system is regarded as an important technique for the hybrid system. Its primary function is to autonomously identify the appropriate quantity of energy that will be supplied by the hybrid source to meet the demand in terms of the load's energy requirements. The primary purpose in this work is the design and validation of an energy management technique based on the state machine and the passivity-based control to manage and control the energy flow of a hybrid fuel cell vehicle's power source, with a fuel cell system serving as the primary source of power and batteries and supercapacitors serving as the secondary sources of power. The results of MATLAB simulations show that the proposed strategy works as expected and the control system has robust dynamic features. Consequently, the passivity-based control makes possible to globally control the hybrid system which has been presented by a state space model in order to reach a set of stable equilibria. Whereas, the state machine is efficient in terms of performance, easy to implement, and provides ideal balance between the amount of energy that is generated and the amount that is consumed.
{"title":"Robust State Machine Passivity-based Control Applied to Fuel Cell Hybrid Source","authors":"Mohammed Messaoud, Kraa Okba, Tegani Ilyes","doi":"10.46904/eea.22.70.4.1108002","DOIUrl":"https://doi.org/10.46904/eea.22.70.4.1108002","url":null,"abstract":"The disadvantages of fuel cell systems, such as their high cost, lack of reactivity, and inability to collect energy when the fuel cell vehicle is braking, can be overcome by hybridization with storage devices such the battery or the supercapacitors, which is capable of doing so. The energy management system is regarded as an important technique for the hybrid system. Its primary function is to autonomously identify the appropriate quantity of energy that will be supplied by the hybrid source to meet the demand in terms of the load's energy requirements. The primary purpose in this work is the design and validation of an energy management technique based on the state machine and the passivity-based control to manage and control the energy flow of a hybrid fuel cell vehicle's power source, with a fuel cell system serving as the primary source of power and batteries and supercapacitors serving as the secondary sources of power. The results of MATLAB simulations show that the proposed strategy works as expected and the control system has robust dynamic features. Consequently, the passivity-based control makes possible to globally control the hybrid system which has been presented by a state space model in order to reach a set of stable equilibria. Whereas, the state machine is efficient in terms of performance, easy to implement, and provides ideal balance between the amount of energy that is generated and the amount that is consumed.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84683360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Changing the existing medium voltage alternating current cable to transmit direct current is a feasible technical transformation scheme, which has obvious advantages in cable capacity increase and operation reliability improvement. At present, there is only one project case introduced in the alternating current to direct current conversion of medium voltage alternating current cables. Most of the studies are carried out from the perspective of theoretical analysis and design calculation. The research focuses on the constraints of alternating current to direct current conversion of different cables and the design of ampacity and voltage. This paper studies the design method of converting the existing alternating current cable to direct current, analyses some problems in the current design and the technical details that need to be further improved, and discusses the constraints of converting the medium voltage alternating current cable to direct current from the aspects of current carrying capacity design, system design and system design, insulation temperature difference and electric field inversion, voltage design, space charge accumulation threshold calculation, electrical type test, etc. On this basis, this paper puts forward a design idea of alternating current to direct current transformation of medium voltage alternating current cable based on comprehensive constraints and suitable for practical engineering transformation and makes an example calculation. Finally, it gives implementation suggestions for the electrical type test of alternating current to direct current transformation of medium voltage alternating current cable.
{"title":"Design Method of Changing Medium Voltage Alternating-Current Cable to Direct-Current Operation","authors":"Xiao Han, Xiongjun Liu, Junguo Gao, Longxiao Chen, Chendan Tang","doi":"10.46904/eea.22.70.4.1108006","DOIUrl":"https://doi.org/10.46904/eea.22.70.4.1108006","url":null,"abstract":"Changing the existing medium voltage alternating current cable to transmit direct current is a feasible technical transformation scheme, which has obvious advantages in cable capacity increase and operation reliability improvement. At present, there is only one project case introduced in the alternating current to direct current conversion of medium voltage alternating current cables. Most of the studies are carried out from the perspective of theoretical analysis and design calculation. The research focuses on the constraints of alternating current to direct current conversion of different cables and the design of ampacity and voltage. This paper studies the design method of converting the existing alternating current cable to direct current, analyses some problems in the current design and the technical details that need to be further improved, and discusses the constraints of converting the medium voltage alternating current cable to direct current from the aspects of current carrying capacity design, system design and system design, insulation temperature difference and electric field inversion, voltage design, space charge accumulation threshold calculation, electrical type test, etc. On this basis, this paper puts forward a design idea of alternating current to direct current transformation of medium voltage alternating current cable based on comprehensive constraints and suitable for practical engineering transformation and makes an example calculation. Finally, it gives implementation suggestions for the electrical type test of alternating current to direct current transformation of medium voltage alternating current cable.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78879392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.46904/eea.22.70.3.1108005
A. Laifaoui, Mohand-Seghir Herzine, H. Ait Said, J. Reboul
In this work, we present an experimental study on electrical breakdown, also called dielectric failure on a material widely used as insulation in oil transformers and other equipment. This material is pressboard paper impregnated with insulating oil. The breakdown tests are carried out under three types of voltage and for several voltage rise speeds. Dielectric breakdown is a random phenomenon, many tests are carried out on a large number of samples and the results obtained have been subjected to statistical processing. The material is cut into square plates of 7.5 cm in length from a set of plates 2 m² in length and 500 µm in thickness. Prior to the tests, the samples were conditioned in a desiccator with silicone gel for at least 24 hours in order to eliminate any presence of moisture. Then they were impregnated with Borak22 insulating oil for at least one week. The tests consist of placing the sample concerned between two cylindrical bronze electrodes and applying a voltage ramp at constant speed until breakdown. After failure, the value of the breakdown voltage is taken. These tests are carried out in the laboratory at room temperature. However, we have tried to reproduce the same conditions for all the tests. These various tests relate to the effect of the form and the rate of rise of the applied voltage on the dielectric strength of the pressboard paper impregnated with Borak22 insulating oil. Two measuring devices were used, and the tests were carried out under three voltage forms: sinusoidal alternating current, continuous positive polarity, and continuous negative polarity, and at eight different voltage ramp speeds: 0,69; 1,07; 1,4; 1,89; 2,38; 2,94; 3,28 and 4,17 kV/s. For each measurement point, 35 samples of pressboard paper are used and tested. A total of 840 results were obtained and processed using the two-parameter Weibull statistical model. In order to validate this model, these results are subjected to a Kolmogorov-Smirnov adequacy test and are framed by 95% confidence bands. The maximum likelihood method is used for the estimation of the Weibull parameters and the smoothing of the experimental points. The results of the statistical tests on the breakdown voltage measurement points obtained confirm the use of the two-parameter Weibull model. The evolution of the nominal breakdown voltage as a function of the voltage ramp of the three forms of applied voltage gives three properties of the same form, which is akin to the letter 'S'. The breakdown voltage first increases linearly for low speeds, then increases and takes an exponential form for medium speeds, then tends towards a certain saturation for high speeds. The breakdown voltage under the DC voltage ramp is higher than the voltage obtained for the AC voltage ramp and are higher under negative polarity voltage than those under positive polarity voltage.
{"title":"Electrical Breakdown of Oil-Impregnated Pressboard under AC and DC Voltages Ramp","authors":"A. Laifaoui, Mohand-Seghir Herzine, H. Ait Said, J. Reboul","doi":"10.46904/eea.22.70.3.1108005","DOIUrl":"https://doi.org/10.46904/eea.22.70.3.1108005","url":null,"abstract":"In this work, we present an experimental study on electrical breakdown, also called dielectric failure on a material widely used as insulation in oil transformers and other equipment. This material is pressboard paper impregnated with insulating oil. The breakdown tests are carried out under three types of voltage and for several voltage rise speeds. Dielectric breakdown is a random phenomenon, many tests are carried out on a large number of samples and the results obtained have been subjected to statistical processing. The material is cut into square plates of 7.5 cm in length from a set of plates 2 m² in length and 500 µm in thickness. Prior to the tests, the samples were conditioned in a desiccator with silicone gel for at least 24 hours in order to eliminate any presence of moisture. Then they were impregnated with Borak22 insulating oil for at least one week. The tests consist of placing the sample concerned between two cylindrical bronze electrodes and applying a voltage ramp at constant speed until breakdown. After failure, the value of the breakdown voltage is taken. These tests are carried out in the laboratory at room temperature. However, we have tried to reproduce the same conditions for all the tests. These various tests relate to the effect of the form and the rate of rise of the applied voltage on the dielectric strength of the pressboard paper impregnated with Borak22 insulating oil. Two measuring devices were used, and the tests were carried out under three voltage forms: sinusoidal alternating current, continuous positive polarity, and continuous negative polarity, and at eight different voltage ramp speeds: 0,69; 1,07; 1,4; 1,89; 2,38; 2,94; 3,28 and 4,17 kV/s. For each measurement point, 35 samples of pressboard paper are used and tested. A total of 840 results were obtained and processed using the two-parameter Weibull statistical model. In order to validate this model, these results are subjected to a Kolmogorov-Smirnov adequacy test and are framed by 95% confidence bands. The maximum likelihood method is used for the estimation of the Weibull parameters and the smoothing of the experimental points. The results of the statistical tests on the breakdown voltage measurement points obtained confirm the use of the two-parameter Weibull model. The evolution of the nominal breakdown voltage as a function of the voltage ramp of the three forms of applied voltage gives three properties of the same form, which is akin to the letter 'S'. The breakdown voltage first increases linearly for low speeds, then increases and takes an exponential form for medium speeds, then tends towards a certain saturation for high speeds. The breakdown voltage under the DC voltage ramp is higher than the voltage obtained for the AC voltage ramp and are higher under negative polarity voltage than those under positive polarity voltage.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84454173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.46904/eea.22.70.3.1108002
Wang Qianqian, Liu Weili, Tang Minan, Zhang Kaiyue
The compensation capacitor fault of jointless track circuit has an important impact on the safe operation of high-speed trains. In order to solve the problem of multiple compensation capacitors breaking at the same time in jointless track circuit, a fault diagnosis method based on the amplitude characteristics of induced voltage envelope curve is proposed. Firstly, the shunt state model of track circuit is established, and the envelope curves of induced voltage amplitude corresponding to the disconnection fault of compensation capacitors at different positions are obtained by simulating analysis. Secondly, taking the distance between adjacent compensation capacitors as a step, the envelope curves of induced voltage amplitude corresponding to the faults of compensation capacitors at different positions are calculated, and the curves are segmented by according to the half step distance, and the eigenvalues of each segment are computed. Thirdly, the characteristic values of each segment are detected from the transmitter to the receiver to find the specific values, so as to realize the preliminary fault diagnosis of the compensation capacitor. Then, in order to make the fault diagnosis of compensation capacitor more accurate, according to the unique fault type, the slope is employed as the constraint condition for secondary diagnosis, so as to locate the fault capacitor position when multiple compensation capacitors break at the same time. Finally, by building a simulation platform and selecting the actual data of a road section, the proposed method is verified and compared. The results show that the algorithm can diagnose the position of the fault capacitor when multiple compensation capacitors on the track circuit break at the same time. The accuracy of the proposed algorithm is 99.04%, and it has high real-time performance.
{"title":"Diagnosis Method for Multiple Compensation Capacitor Faults of Jointless Track Circuit","authors":"Wang Qianqian, Liu Weili, Tang Minan, Zhang Kaiyue","doi":"10.46904/eea.22.70.3.1108002","DOIUrl":"https://doi.org/10.46904/eea.22.70.3.1108002","url":null,"abstract":"The compensation capacitor fault of jointless track circuit has an important impact on the safe operation of high-speed trains. In order to solve the problem of multiple compensation capacitors breaking at the same time in jointless track circuit, a fault diagnosis method based on the amplitude characteristics of induced voltage envelope curve is proposed. Firstly, the shunt state model of track circuit is established, and the envelope curves of induced voltage amplitude corresponding to the disconnection fault of compensation capacitors at different positions are obtained by simulating analysis. Secondly, taking the distance between adjacent compensation capacitors as a step, the envelope curves of induced voltage amplitude corresponding to the faults of compensation capacitors at different positions are calculated, and the curves are segmented by according to the half step distance, and the eigenvalues of each segment are computed. Thirdly, the characteristic values of each segment are detected from the transmitter to the receiver to find the specific values, so as to realize the preliminary fault diagnosis of the compensation capacitor. Then, in order to make the fault diagnosis of compensation capacitor more accurate, according to the unique fault type, the slope is employed as the constraint condition for secondary diagnosis, so as to locate the fault capacitor position when multiple compensation capacitors break at the same time. Finally, by building a simulation platform and selecting the actual data of a road section, the proposed method is verified and compared. The results show that the algorithm can diagnose the position of the fault capacitor when multiple compensation capacitors on the track circuit break at the same time. The accuracy of the proposed algorithm is 99.04%, and it has high real-time performance.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85510805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.46904/eea.22.70.3.1108003
L. Pîslaru-Dănescu, I. Fuiorea, A. Dumitru, L. Flore, Ionel Popescu, R. Chihaia
Firstly, the paper presents a solid solution of piezoelectric ceramic that was synthesized according to the general formula Pb(1-x)Srx(Ti0.48Zr0.52)(1-y)NbyO3 with x = 0.05 and y = 0.02, using wet ceramic processing technology and using oxides as prime materials. The effects of dopants (Sr2+ and Nb5+) on phase constitution, on microstructure and on the dielectric and piezoelectric properties were determined. The Zr4+/Ti4+ ratio was chosen near the morphotropic phase boundary of the lead zirconate titanate (PZT) system in studied composition. The XRD data revealed that the PZT doped composition had tetragonal perovskite structure. Secondly, based on piezoelectric properties of this ceramic, the paper presents the design of the ultrasonic piezo-motor based on a surface wave, which translates the linear extension of different piezoelectric segments of a piezoelectric cylinder into a rotational bending movement. This rotational bending of the piezoelectric cylinder is then transformed into a continuous rotation of the rotor through a calculated contact. A mathematical model and the numerical simulations of ultrasonic piezo-motor is presented. The numerical simulation has been performed in two different cases: an idle-case, where no external opposition torque was applied to the rotor, and a maximum torque case, where the rotor was blocked to calculate the maximum torque that the motor could produce.
首先，采用湿法陶瓷加工工艺，以氧化物为主要材料，根据通式Pb(1-x)Srx(Ti0.48Zr0.52)(1-y)NbyO3 (x = 0.05, y = 0.02)合成了压电陶瓷固溶体。研究了掺杂剂Sr2+和Nb5+对复合材料相组成、微观结构以及介电和压电性能的影响。Zr4+/Ti4+比值选择在锆钛酸铅(PZT)体系的亲晶相边界附近。XRD分析结果表明，PZT掺杂物具有四方钙钛矿结构。其次，基于该陶瓷的压电特性，设计了基于表面波的超声压电电机，将压电圆柱体不同压电片的线性延伸转化为旋转弯曲运动。压电圆柱体的旋转弯曲通过计算接触转化为转子的连续旋转。建立了超声压电电机的数学模型并进行了数值模拟。在两种不同的情况下进行了数值模拟:一种是空转情况，转子上没有施加外部反对扭矩;另一种是最大扭矩情况，转子被阻塞，以计算电机可以产生的最大扭矩。
{"title":"Modelling and Numerical Simulation of an Ultrasonic Piezo-Motor based on Piezoelectric Properties of Pb(1-x)Srx(Ti0,48Zr0,52)(1-y)NbyO3 Ceramics","authors":"L. Pîslaru-Dănescu, I. Fuiorea, A. Dumitru, L. Flore, Ionel Popescu, R. Chihaia","doi":"10.46904/eea.22.70.3.1108003","DOIUrl":"https://doi.org/10.46904/eea.22.70.3.1108003","url":null,"abstract":"Firstly, the paper presents a solid solution of piezoelectric ceramic that was synthesized according to the general formula Pb(1-x)Srx(Ti0.48Zr0.52)(1-y)NbyO3 with x = 0.05 and y = 0.02, using wet ceramic processing technology and using oxides as prime materials. The effects of dopants (Sr2+ and Nb5+) on phase constitution, on microstructure and on the dielectric and piezoelectric properties were determined. The Zr4+/Ti4+ ratio was chosen near the morphotropic phase boundary of the lead zirconate titanate (PZT) system in studied composition. The XRD data revealed that the PZT doped composition had tetragonal perovskite structure. Secondly, based on piezoelectric properties of this ceramic, the paper presents the design of the ultrasonic piezo-motor based on a surface wave, which translates the linear extension of different piezoelectric segments of a piezoelectric cylinder into a rotational bending movement. This rotational bending of the piezoelectric cylinder is then transformed into a continuous rotation of the rotor through a calculated contact. A mathematical model and the numerical simulations of ultrasonic piezo-motor is presented. The numerical simulation has been performed in two different cases: an idle-case, where no external opposition torque was applied to the rotor, and a maximum torque case, where the rotor was blocked to calculate the maximum torque that the motor could produce.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84974819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.46904/eea.22.70.3.1108006
Y. Nurhasanah, Mira Musrini Barmawi, Ramsza Prakarsa
Home automation is an IoT technology that has the ability to communicate between devices. This technology requires a method for making the decision process. Fuzzy logic method is a solution to this problem. Fuzzy Logic is a method that functions to replicate and run human knowledge to control a system. In fuzzy logic algorithm, there are three main processes, which are fuzzification, inference, and defuzzification. Defuzzification process requires a method to obtain the value of crisp solutions. One of the many methods is Mean of Maximum (MoM). MoM is an algorithm that calculates the average of fuzzy conclusions or outputs that have the highest degree. In this research, we apply the MoM method in the defuzzification process to build a smoke emission control system in a room using an exhaust fan. Wemos D1 mini is used as a controller and processor in the system. And using telegram chatbot for communication media between users and the system. There are 27 rules in this system with 100% functionality. This research topic is very useful to keep the air clean and fresh in the room and avoid the dangers of cigarette smoke that can damage health.
{"title":"Implementation of Mean of Maximum on Cigarette Smoke Control in a Room","authors":"Y. Nurhasanah, Mira Musrini Barmawi, Ramsza Prakarsa","doi":"10.46904/eea.22.70.3.1108006","DOIUrl":"https://doi.org/10.46904/eea.22.70.3.1108006","url":null,"abstract":"Home automation is an IoT technology that has the ability to communicate between devices. This technology requires a method for making the decision process. Fuzzy logic method is a solution to this problem. Fuzzy Logic is a method that functions to replicate and run human knowledge to control a system. In fuzzy logic algorithm, there are three main processes, which are fuzzification, inference, and defuzzification. Defuzzification process requires a method to obtain the value of crisp solutions. One of the many methods is Mean of Maximum (MoM). MoM is an algorithm that calculates the average of fuzzy conclusions or outputs that have the highest degree. In this research, we apply the MoM method in the defuzzification process to build a smoke emission control system in a room using an exhaust fan. Wemos D1 mini is used as a controller and processor in the system. And using telegram chatbot for communication media between users and the system. There are 27 rules in this system with 100% functionality. This research topic is very useful to keep the air clean and fresh in the room and avoid the dangers of cigarette smoke that can damage health.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78013451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.46904/eea.22.70.3.1108004
Titu-Marius I. Băjenescu
FET’s have become increasingly popular as possible replacements for microwave electron tubes and solid-state active diodes. Reliability is extremely important for these devices when used in communication systems, especially for space applications. The reliability of small, signal GaAs FET’s has been extensively investigated. As a result, the reliability of small-signal or low-noise devices is fairly well understood, and the essential problems are practically solved. However, the reliability of power devices is much more complicated because they are expected to operate in the vicinity of their maximum capability of voltage, current, or power dissipation, in the presence of large RF signals.
{"title":"Power FETs: Failure Analysis (FA) and Reliability Analysis (RA)","authors":"Titu-Marius I. Băjenescu","doi":"10.46904/eea.22.70.3.1108004","DOIUrl":"https://doi.org/10.46904/eea.22.70.3.1108004","url":null,"abstract":"FET’s have become increasingly popular as possible replacements for microwave electron tubes and solid-state active diodes. Reliability is extremely important for these devices when used in communication systems, especially for space applications. The reliability of small, signal GaAs FET’s has been extensively investigated. As a result, the reliability of small-signal or low-noise devices is fairly well understood, and the essential problems are practically solved. However, the reliability of power devices is much more complicated because they are expected to operate in the vicinity of their maximum capability of voltage, current, or power dissipation, in the presence of large RF signals.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88944631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.46904/eea.22.70.3.1108001
L. Pîslaru-Dănescu, G. Zărnescu, V. Stoica
This study addresses a sensitive topic, namely how human subjects undergoing medical procedures can be protected by means of medical electrical equipment. A solution to this problem is to monitor the stabilized electrical supply voltages of the medical equipment. The net effect of the proposed protection is the automatic disconnection of the medical equipment from the alternating voltage network supplying the medical equipment. This disconnection must be done without using electrical switching devices that contain electrical contacts that can generate electrical sparks. This is because most of the time the medical equipment is placed in an area where pure oxygen or other combustible gases predominate. Therefore, only static relays are used in this case. The realized electronic module has been tested in the laboratory and is capable of automatic disconnection of any medical equipment from the 230 V~, f = 50 Hz AC power supply in the case of major faults, which can be caused by accidental overvoltage on the electric energy supply lines, accidental overtemperatures, transient overvoltage which are propagated during storms, etc. This study presents the transient phenomena that occur in the immediate vicinity of the monitored voltages range. Finally, a solution for simultaneous monitoring of four electric voltages and/or currents is presented.
本研究涉及一个敏感话题，即如何通过医疗电气设备保护接受医疗程序的人类受试者。解决这个问题的一种方法是监测医疗设备的稳定电源电压。所建议的保护的净效果是自动断开医疗设备与供应医疗设备的交流电压网络的连接。这种断开必须在不使用包含可能产生电火花的电触点的电气开关设备的情况下进行。这是因为大多数时候，医疗设备被放置在纯氧或其他可燃气体占主导地位的区域。因此，在这种情况下只使用静态继电器。所实现的电子模块已经过实验室测试，能够在供电线路意外过电压、意外过温、风暴传播的瞬态过电压等重大故障时，自动断开任何医疗设备与230 V~， f = 50 Hz交流电源的连接。本研究提出了发生在被监测电压范围附近的暂态现象。最后，提出了一种同时监测四个电压和/或电流的解决方案。
{"title":"Human Subjects Protection by Monitoring the Stabilized Supply Voltages of the Medical Equipment","authors":"L. Pîslaru-Dănescu, G. Zărnescu, V. Stoica","doi":"10.46904/eea.22.70.3.1108001","DOIUrl":"https://doi.org/10.46904/eea.22.70.3.1108001","url":null,"abstract":"This study addresses a sensitive topic, namely how human subjects undergoing medical procedures can be protected by means of medical electrical equipment. A solution to this problem is to monitor the stabilized electrical supply voltages of the medical equipment. The net effect of the proposed protection is the automatic disconnection of the medical equipment from the alternating voltage network supplying the medical equipment. This disconnection must be done without using electrical switching devices that contain electrical contacts that can generate electrical sparks. This is because most of the time the medical equipment is placed in an area where pure oxygen or other combustible gases predominate. Therefore, only static relays are used in this case. The realized electronic module has been tested in the laboratory and is capable of automatic disconnection of any medical equipment from the 230 V~, f = 50 Hz AC power supply in the case of major faults, which can be caused by accidental overvoltage on the electric energy supply lines, accidental overtemperatures, transient overvoltage which are propagated during storms, etc. This study presents the transient phenomena that occur in the immediate vicinity of the monitored voltages range. Finally, a solution for simultaneous monitoring of four electric voltages and/or currents is presented.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73410617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-15DOI: 10.46904/eea.22.70.2.1108003
Dongliang Sun, Qunhua Dong
The difference between the single air laying ampacity test value of medium voltage power cable and the system ampacity of three-phase laying and operation is a common problem in the industry. Based on the TICW-2012 standard, the single cable ampacity of medium voltage single core power cable is tested, and the COMSOL basic simulation model is debugged with the measured ampacity value. On the premise of correct single cable basic simulation model, the system ampacity under three-phase operation under different working conditions is calculated, including triangular laying, plane laying, single circuit and double circuit laying, The difference and correction coefficient between the test current carrying capacity and the of single air laying of medium voltage single core power cable are further analysed. Finally, the analytical formula is derived through the cable ampacity equivalent thermal circuit diagram, and the cable samples are theoretically analysed and calculated. According to the ampacity calculation results of single loop triangular laying and plane laying, the correctness of the simulation results is verified. This study provides a reference basis for the current carrying capacity test and correction of medium voltage power cable in the future, and also provides an effective method for the actual operation state analysis of medium voltage power cable.
{"title":"Cable Steady-State Ampacity Correction Method based on Multi Physical Field Coupling Algorithm","authors":"Dongliang Sun, Qunhua Dong","doi":"10.46904/eea.22.70.2.1108003","DOIUrl":"https://doi.org/10.46904/eea.22.70.2.1108003","url":null,"abstract":"The difference between the single air laying ampacity test value of medium voltage power cable and the system ampacity of three-phase laying and operation is a common problem in the industry. Based on the TICW-2012 standard, the single cable ampacity of medium voltage single core power cable is tested, and the COMSOL basic simulation model is debugged with the measured ampacity value. On the premise of correct single cable basic simulation model, the system ampacity under three-phase operation under different working conditions is calculated, including triangular laying, plane laying, single circuit and double circuit laying, The difference and correction coefficient between the test current carrying capacity and the of single air laying of medium voltage single core power cable are further analysed. Finally, the analytical formula is derived through the cable ampacity equivalent thermal circuit diagram, and the cable samples are theoretically analysed and calculated. According to the ampacity calculation results of single loop triangular laying and plane laying, the correctness of the simulation results is verified. This study provides a reference basis for the current carrying capacity test and correction of medium voltage power cable in the future, and also provides an effective method for the actual operation state analysis of medium voltage power cable.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79137352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-15DOI: 10.46904/eea.22.70.2.1108001
Titu-Marius I. Băjenescu
Today, most of the companies understand that the reliability must be built in at the design phase and then, monitored during the whole manufacturing process. Reliability building means the totality of techniques and procedures having the goal to ensure a foreseen reliability level for a given product. This concept is linked with reliability assessing, which cover the whole evaluation system aiming to find out and record, during and after the manufacturing process, the reliability level of the batch of products. This evaluation system contains tests, electrical measurements, failure analysis and statistical processing of data.
{"title":"Quality and Reliability Evolution of Electronic Components","authors":"Titu-Marius I. Băjenescu","doi":"10.46904/eea.22.70.2.1108001","DOIUrl":"https://doi.org/10.46904/eea.22.70.2.1108001","url":null,"abstract":"Today, most of the companies understand that the reliability must be built in at the design phase and then, monitored during the whole manufacturing process. Reliability building means the totality of techniques and procedures having the goal to ensure a foreseen reliability level for a given product. This concept is linked with reliability assessing, which cover the whole evaluation system aiming to find out and record, during and after the manufacturing process, the reliability level of the batch of products. This evaluation system contains tests, electrical measurements, failure analysis and statistical processing of data.","PeriodicalId":38292,"journal":{"name":"EEA - Electrotehnica, Electronica, Automatica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87833330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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