scholarly journals A single-phase simplified DC-AC converter using DC-link capacitors and an H-bridge

2021 ◽  
Vol 10 (6) ◽  
pp. 2964-2971
Author(s):  
Sai Divya Sindhura Nunna ◽  
Akhilesh Ketha ◽  
Srivastav Sai Goud Padamat ◽  
K. Rambabu ◽  
Ujwala Anil Kshirsagar ◽  
...  

This paper introduces a simplified inverter circuit using a single dc source and an H-bridge with a least possible number of “switching devices”. This topology does not employ multiple “dc sources”, which enhances the reliability of the configuration. The topology consists of two parts, namely: “Level generation parts” as well as “Polarity generation parts”, it is the mixture of some of the switching devices, DC-link capacitor and a single DC source completes the part of level generation. The H-bridge in the proposed structure produces the polarity generation part. A detailed explanation of the modulation system and operating modes of the proposed framework are discussed. Finally, in the MATLAB/SIMULINK platform, the projected network topology is simulated and the outcomes are presented.

2018 ◽  
Vol 7 (4.6) ◽  
pp. 177
Author(s):  
Kiran Kumar Nallamekala ◽  
K. Venkat Raman ◽  
Md. Asif

Multi-level inverters are playing a major role in PV based systems because of numerous advantages like low dv/dt, better harmonic profile so on. But, conventional multi-level inverters consist of some drawbacks like capacitor balancing issues, greater requirement of capacitor banks and clamping diodes. To address these issues, a novel multi-level inverter has been presented in this paper, which can function as a seven-level, five-level and three-level inverter. The inverter circuit utilizes six switching devices and two isolated DC voltage sources.  Moreover, when it is operated as a three-level inverter, a unipolar PWM technique is applied to the circuit which shifts all the lower order harmonics to twice of switching frequency whereas in conventional multi-level inverters, all the harmonics of lower order are present around switching frequency. In addition, proposed inverter can operate even if some switching devices of the circuit fails. Also, the behavior of the inverter during the failure of some switching devices and DC source is analyzed. The proposed inverter is simulated in MATLAB/Simulink and the results are also discussed.  


Author(s):  
Siva Pachipala ◽  
Amarsrinadh Guda ◽  
Mentimi Sandeep Babu ◽  
Veeranarayana B. ◽  
K. V. S. Ramachandra Murthy ◽  
...  

An inverter circuit is promoted in this paper, using series-connected switched dc sources along with an H-bridge circuit with optimized circuit elements like switching devices and diode clamped (DC) sources. This configuration uses DC supplies that can be strung together in series to create a significant voltage level. This topology consists of two parts, namely: 1) level production part and 2) polarity production part. The combination of some of the dc sources and switching devices completes the level production part. The H-bridge in the presented structure produces the polarity generation part. The DC-link capacitors are not needed in this design. There is a full presentation of the operating modes and modeling process of the proposed converter. Finally, in the MATLAB/SIMULINK setting the proposed topology is simulated and output current and voltage results have been examined.


Author(s):  
Zhenxing Li ◽  
Jialing Wan ◽  
Pengfei Wang ◽  
Hanli Weng ◽  
Zhenhua Li

AbstractFault section location of a single-phase grounding fault is affected by the neutral grounding mode of the system, transition resistance, and the blind zone. A fault section locating method based on an amplitude feature and an intelligent distance algorithm is proposed to eliminate the influence of the above factors. By analyzing and comparing the amplitude characteristics of the zero-sequence current transient components at both ends of the healthy section and the faulty section, a distance algorithm with strong abnormal data immune capability is introduced in this paper. The matching degree of the amplitude characteristics at both ends of the feeder section are used as the criterion and by comparing with the set threshold, the faulty section is effectively determined. Finally, simulations using Matlab/Simulink and PSCAD/EMTDC show that the proposed section locating method can locate the faulty section accurately, and is not affected by grounding mode, grounding resistance, or the blind zone.


2021 ◽  
pp. 74-83
Author(s):  
YURI D. VOLCHKOV ◽  

Abstract. The load current aff ects the value of the short-circuit current in the electric network and, consequently, the voltage value. In some cases, this infl uence must be taken into account for the correct choice of switching devices, remote monitoring the operating modes of electric networks, and determining the modes. It is possible to disconnect loads connected through magnetic starters and contactors. Failure to consider the infl uence of the load current can lead to an incorrect interpretation of the identifi ed grid operating modes during remote monitoring and, as a result, incorrect dispatcher’s decisions. In addition, it is also insuffi cient to specify the choice of switching devices in the 10 kV feed network. The article describes a method for analyzing the three-phase short circuit mode in a 10 kV feed network, taking into account the infl uence of load currents. The method is exemplifi ed by the case of an actual electric network – the 10 kV ring feed network containing reclosers and receiving power from diff erent sections of lowvoltage buses of the “Kulikovskaya” 110/35/10 kV substation, belonging to the Branch of PJSC «DGC of Center”-“Orelenergo.” For this network, the values of the three-phase short-circuit currents at points with diff erent distances from the substation buses have been determined. The authors have fi guredout the values of the load currents and their shares in the total short-circuit current. The voltage values at different points of the network in the case of short circuits have also been determined. The research proves that the effect of the load current on the total short-circuit current should be taken into account for the case of remote short circuits.


2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Naveed Ashraf ◽  
Tahir Izhar ◽  
Ghulam Abbas

The suggested single-phase ac-to-ac matrix converter operated with inverting and noninverting characteristics may solve the grid voltage swell and sag problem in power distribution system, respectively. It is also employed as a direct frequency changer for domestic induction heating. The output voltage is regulated through duty cycle control of high frequency direct PWM (DPWM) and indirect PWM (IDPWM) switching devices. The DPWM control switches control the switching states of IDPWM switching devices. The inverting and noninverting characteristics are achieved with low voltage stresses and hence low dv/dt across the high and low frequency-controlled switches. This reduces their voltage rating and losses. The high voltage overshoot problem in frequency step-up operation is also analyzed. The sliding mode (SM) controller is employed to solve this problem. Pulse selective approach determines the power quality of load voltage. The validity of the mathematically computed values is carried out by modelling the proposed topology in MATLAB/Simulink environment and through hardware results.


2019 ◽  
Vol 29 (01) ◽  
pp. 2050004
Author(s):  
Sidharth Sabyasachi ◽  
Vijay B. Borghate ◽  
Santosh Kumar Maddugari

This paper presents a module for single-phase multilevel inverter topology. The proposed module generates maximum 21-level bipolar output voltage with asymmetric sources without H-bridge. This results in reduction in filter cost and size. The module can be cascaded for high voltage applications. The same arrangement of voltage source magnitudes in first module is maintained in the remaining cascaded modules. The proposed topology is suitable for the applications like electric vehicle and emergency services like residences and hospitality industries, etc. A set of comparisons between the proposed and recently published topologies are provided to differentiate between them. The topology is simulated and verified in MATLAB/SIMULINK. A hardware prototype is developed in the laboratory for experimental confirmation with various conditions.


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