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1
Duong, Truong-Duy, Minh-Khai Nguyen, Tan-Tai Tran, Young-Cheol Lim, and Joon-Ho Choi. "Transformer-Less Switched-Capacitor Quasi-Switched Boost DC-DC Converter." Energies 14, no. 20 (2021): 6591. http://dx.doi.org/10.3390/en14206591.
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In this article, a quasi-switched boost converter based on the switched-capacitor technique with high step-up voltage capability is dealt with and analyzed. The proposed converter offers a simple structure and low voltage stress on the semiconductor elements with intrinsic small duty cycle. An inductor of the proposed converter is connected in series with the input voltage source; therefore, continuous input current ripple is attainable. In addition, the efficiency of the proposed converter is also improved. A detailed steady-state analysis is discussed to identify the salient features of the switched-capacitor-based quasi-switched boost DC-DC converter. The performance of the converter is compared against similar existing high boost DC-DC converters. Finally, the switched-capacitor-based quasi-switched boost DC-DC converter is investigated by experimental verification.
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Ijas, Mohammed, George Anu, Issac Kavitha, and James Geethu. "Modified Transformer-Less Single Switch High Voltage Gain Boost Converter." International Journal of Innovative Science and Research Technology 7, no. 11 (2022): 241–47. https://doi.org/10.5281/zenodo.7349408.
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The transformer-less single-switch dualinductor boost converter configuration can realize high voltage gain with low voltage and current stresses; therefore, it is suitable for high gain applications. It has low voltage stress on components compared to other typical transformer-less single-switch high voltage gain converters like switched inductor boost converter, quadratic boost converter and quasi-Z-source boost converter. Moreover, the current stress of the front-end diode and the rear- end inductor is also relatively low. Therefore, the conversion efficiency is enhanced while keeping the cost low. The operation principles and steadystate characteristics analysis of the con- verter is discussed in detail. Results are obtained by simulating the converter in MATLAB/SIMULINK R2021b. The simulation results shows that the converter has high voltage gain and achieves a peak efficiency of 89%. The converter is controlled using TMS320F28335 microcontroller. The experimental results obtained from a 6W converter prototype confirm the theoretical considerations and the simulation results.
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Aleesha, P. Ebrahim, M. Varghese Beena, George Reenu, and S. Neema. "Switched Inductor Based Transformer less Buck-Boost Converter For Renewable Energy Application." International Journal of Innovative Science and Research Technology 7, no. 10 (2022): 1902–11. https://doi.org/10.5281/zenodo.7334233.
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In recent years DC-DC converters have found wide applications in industry which have taken a special place with the expansion of the use of renewable energy sources. DC-DC converters with step-down/stepup voltage are required in many applications like electronic products, fuel cell systems, battery powered systems, portable devices, light emitting diode (LED) and electric vehicle. Therefore converters with high voltage con-version ratio, high efficiency, low cost and small size are needed. A switched inductor based converter achieves, high voltage ratio for applications that needs of high voltage, improves the effi-ciency and reduces voltage stress. The Switched Inductor based Transformerless Buck-Boost converter has continuous input and output current. The output voltage ripple of this converter is low and the voltage stress across switch and diodes are slight and lower than the converters output voltage. Results are obtained by simulating the converter in MATLAB/ SIMULINK R2021b. The simulation results shows that the Switched Inductor based Transformerless Buck-Boost converter has high voltage gain and achieves a peak efficiency of 96%
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P, Maithili, and Kanakaraj J. "Transformer Less Self-Commutated PV Inverter." Regular issue 10, no. 8 (2021): 1–4. http://dx.doi.org/10.35940/ijitee.g9037.0610821.
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The power demand is increased day by day and generation of electrical energy from non-renewable sources are not able to meet the demand. An alternate energy sources are the only solution to meet the power demand. The power generation from solar energy with photovoltaic effect is plays a major role. This Solar PV system has low efficiency. The power semiconductor devices and converter circuit along with inductive / magnetic circuit. The Inverter circuit have an influence on photovoltaic power generation to improve the level of output voltage along with efficiency. In this paper a new transformer less DC-AC converter is proposed, and it has high efficiency, requires less cost when compares with conventional inverter with transformer. Transformer less self-commutated photovoltaic inverter is reflected the advantages of central and string inverters. It gives high output power and low-cost converter. These transformer less DC-AC converter is connect with Boost/Buck-Boost converter for the better output. So, this proposed DC-AC converter topology is not required mechanical switching and it is lighter in size. The PV technology has low efficiency and utilize more cost for generation of power. The proposed transformer less PV inverter is the better choice to increase the usefulness and reduce the charge rate of this PV system.
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Maithili, P., and J. Kanakaraj. "Transformer Less Self-Commutated PV Inverter." International Journal of Innovative Technology and Exploring Engineering (IJITEE) 10, no. 8 (2021): 1–4. https://doi.org/10.35940/ijitee.G9037.0610821.
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The power demand is increased day by day and generation of electrical energy from non-renewable sources are not able to meet the demand. An alternate energy sources are the only solution to meet the power demand. The power generation from solar energy with photovoltaic effect is plays a major role. This Solar PV system has low efficiency. The power semiconductor devices and converter circuit along with inductive / magnetic circuit. The Inverter circuit have an influence on photovoltaic power generation to improve the level of output voltage along with efficiency. In this paper a new transformer less DC-AC converter is proposed, and it has high efficiency, requires less cost when compares with conventional inverter with transformer. Transformer less self-commutated photovoltaic inverter is reflected the advantages of central and string inverters. It gives high output power and low-cost converter. These transformer less DC-AC converter is connect with Boost/Buck-Boost converter for the better output. So, this proposed DC-AC converter topology is not required mechanical switching and it is lighter in size. The PV technology has low efficiency and utilize more cost for generation of power. The proposed transformer less PV inverter is the better choice to increase the usefulness and reduce the charge rate of this PV system.
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Dheeraj, Alagu, and V. Rajini. "Center Clamped Forward Converter for High Current Applications." Journal of Computational and Theoretical Nanoscience 14, no. 1 (2017): 395–402. http://dx.doi.org/10.1166/jctn.2017.6333.
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High current applications like Microprocessors, Fuel cells, Electric Hybrid Vehicles, Solar Cells etc., use interleaved isolated buck derived converter. Interleaving of converters for such high current applications converters is done to achieve reduced input capacitor ripple voltages, output capacitor ripple current cancellation and reduced peak currents of output inductors. Generally, interleaving requires a higher number of transformers through which distributed magnetics can be achieved. i.e., one bulky transformer can be replaced with low power profile transformers. The performance of forward converter depends on core resetting of the main transformer. The core’s magnetizing energy is recycled by resetting it. In the absence of core reset, the current builds up at each switching cycle, saturates the core, causes reverse recovery problem in the diode and the active clamp will no longer in zero voltage state during turn on of the main switch. The transformer secondary output is used as a gating pulse for Synchronous Rectifiers. These have very low forward drop which are most suitable for high current applications. Among various used clamping methods, the transformer core is optimized effectively by Active center clamp reset approach. The proposed method results in less number of switches and clamping capacitor, and lower cost compared to conventional forward converter. Reduction in voltage stress without losing duty-cycle ratio is also achieved by means of a series-parallel connected switch structure with Self Driven Synchronous Rectifiers. The proposed center clamp converter overcomes the Maximum Duty cycle limitation of 50%. This paper mainly focuses on active center clamp forward converter and is also compared with Active Positive Negative clamping techniques.
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Y., Sai Sruthi*1 &. M. Siva Kumar2. "ANALYSIS AND MODELING OF TRANSFORMER LESS HIGH GAIN BUCK-BOOST DC-DC CONVERTER FOR SOLAR ENERGY APPLICATION." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 6, no. 9 (2017): 287–94. https://doi.org/10.5281/zenodo.891738.
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This paper proposes a transformer less buck boost converter model usedfor solar energy application, which provides, higher efficiency and its voltage gain is quadratic of the traditional buck-boost converter. It can operate in a wide range of output voltage, that is, the proposed buck-boost converter can achieve high or low voltage gain without extreme duty cycle. Moreover, the output voltage of this transformer less buck-boost converter is common-ground with the input voltage, and its polarity is positive. The two power switches of the buck-boost converter operate synchronously. The operating principles of the buck-boost converter operating in continuous conduction modes are presented. The new transformerless buck-boost converter is analyzed by providing required DC voltage frompv array as input to the converter. The simulation results are presented to confirm the capability of the converter to generate high voltage ratios. The comparison between the proposed converter and the traditional converter is also analyzed to reveal the improved voltage gain. The proposed converter is suitable for a wide application which requires high step-up DC-DC converters such as DC micro-grids and solar electrical energy.
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Reddy, Lambu Rushi. "A Transformer less Buck Boost Converter with Positive Output Voltage." International Journal for Research in Applied Science and Engineering Technology 9, no. VII (2021): 3575–80. http://dx.doi.org/10.22214/ijraset.2021.37141.
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Some industrial applications require high step-up and step-down voltage gain. The transformer less buck-boost converter has high voltage gain than that of traditional buck-boost converter without extreme duty cycles. A transformer less buck-boost converter with simple structure is obtained by inserting an additional switched network into the traditional buck-boost converter. The two power switches of the buck-boost converter operate synchronously. The operating principles of the buck-boost converter operating in continuous conduction modes are presented. A new buck- boost converter is presented by providing a feedback to the converter. By this, constant output voltage can be maintained under varying load conditions in both buck and boost operation. The output voltage of 40V (step—up mode)/8V (step down mode) is obtained with input voltage 18V and the outcomes are approved through recreation using PSIM MODEL.
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Ameen, Yasir M. Y., Harith Al-Badrani, and Mohamed N. Abdul Kadi. "Design and simulation of a high-power double-output isolated Cuk converter." Eastern-European Journal of Enterprise Technologies 5, no. 5 (113) (2021): 30–38. http://dx.doi.org/10.15587/1729-4061.2021.238984.
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Among the transformer-less DC-DC converters, the superiority of the conventional Cuk converter is obvious in its good properties. However, the output power is limited for all transformer-less converter types including the conventional Cuk converter. In order to get more supplied power from this converter, some changes in its design were necessary. One of these modifications is to add a transformer to transfer more power and to separate the output side from the input side. Supply of some applications such as the DC link of modular multilevel inverters, e. g. cascaded H-bridge (CHB) topologies required more than one output. Hence, this paper is concerned with the design, analysis and simulation of an isolated dual-output modified Cuk converter. The proposed converter is designed to deliver a total output power of 2,000 W using only one modulating switch. A complete design and detailed analysis of the high-frequency transformer with the ANSYS Maxwell platform is presented in this paper. The modeling and simulation results of the high-frequency transformer are validated by the experimental implementation results and good agreement was obtained with a small percentage of errors less than 4 %. A set of analytical equations has been derived and presented in this paper to represent a mathematical model of the converter. In addition, the entire converter circuit was simulated and analyzed with MATLAB/Simulink. The simulation results were checked and compared to the findings of the mathematical model, yielding an excellent match with a percentage error of less than 2.15 %. Finally, when the presented converter was tested under various loads, including unbalanced load situations, a reasonable output voltage regulation was achieved, with the two output voltages being nearly identical with a deviation of less than 0.25 % under a severe unbalanced load condition of 150 %
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Yasir, M. Y. Ameen, Al-Badrani Harith, and N. Abdul Kadi Mohamed. "Design and simulation of a high-power double-output isolated Cuk converter." Eastern-European Journal of Enterprise Technologies 5, no. 5 (113) (2021): 30–38. https://doi.org/10.15587/1729-4061.2021.238984.
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Among the transformer-less DC-DC converters, the superiority of the conventional Cuk converter is obvious in its good properties. However, the output power is limited for all transformer-less converter types including the conventional Cuk converter. In order to get more supplied power from this converter, some changes in its design were necessary. One of these modifications is to add a transformer to transfer more power and to separate the output side from the input side. Supply of some applications such as the DC link of modular multilevel inverters, e. g. cascaded H-bridge (CHB) topologies required more than one output. Hence, this paper is concerned with the design, analysis and simulation of an isolated dual-output modified Cuk converter. The proposed converter is designed to deliver a total output power of 2,000 W using only one modulating switch. A complete design and detailed analysis of the high-frequency transformer with the ANSYS Maxwell platform is presented in this paper. The modeling and simulation results of the high-frequency transformer are validated by the experimental implementation results and good agreement was obtained with a small percentage of errors less than 4 %. A set of analytical equations has been derived and presented in this paper to represent a mathematical model of the converter. In addition, the entire converter circuit was simulated and analyzed with MATLAB/Simulink. The simulation results were checked and compared to the findings of the mathematical model, yielding an excellent match with a percentage error of less than 2.15 %. Finally, when the presented converter was tested under various loads, including unbalanced load situations, a reasonable output voltage regulation was achieved, with the two output voltages being nearly identical with a deviation of less than 0.25 % under a severe unbalanced load condition of 150 %
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Lv, Jinzhuang, Mingchun Hou, Zhicheng Pan, et al. "Measurement Method of Deeply Saturated Excitation Characteristics of Converter Transformer Under AC-DC Hybrid Excitation." Electronics 13, no. 23 (2024): 4691. http://dx.doi.org/10.3390/electronics13234691.
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During operation, converter transformers enter a saturation state, leading to phenomena such as magnetising inrush currents. Accurately measuring the excitation characteristic curve of an iron core under deep-saturation conditions is essential for analysing low-frequency transient phenomena in transformers. This paper presents a method for calculating the excitation characteristics of a converter transformer under deep iron core saturation. The method involves establishing an improved T model for the converter transformer and conducting open-circuit experiments in the linear working region to obtain the excitation characteristic curve and knee point parameters. AC-DC hybrid excitation is used to achieve deep saturation, and measurements of saturated inductance at different levels of saturation at the transformer terminals are taken. The mathematical relationship between saturated inductance and magnetic impedance is derived, allowing deduction of the magnetising characteristic curve of the converter transformer under deep-saturation conditions based on measured saturated inductance values. A finite element simulation analysis was performed on a single-phase four-column converter transformer with a capacity of 250 MVA. Additionally, a test platform for toroidal transformers and dry-type transformers has been set up to carry out excitation characteristic measurement and verification. Experimental results demonstrate that errors are maintained within 10% or less, validating this approach’s effectiveness.
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Dawidziuk, J. "dual inductor-fed boost converter with an auxiliary transformer and voltage doubler." Bulletin of the Polish Academy of Sciences: Technical Sciences 61, no. 4 (2013): 787–91. http://dx.doi.org/10.2478/bpasts-2013-0085.
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Abstract This paper presents a dual inductor-fed boost converter with an auxiliary transformer and voltage doubler for sustainable energy power converters. The new topology integrates a two-phase boost converter and a dual inductor-fed boost converter. The energy stored and transferred by both inductors can attain a wide input-voltage and load range which uses a constant switching frequency, by controlling the time duration of the simultaneous conduction of the two switches. Among other current-fed type boost converters the presented topology is attractive due to the high voltage conversion ratio, less stress on the components and less switch conduction loss. To verify the feasibility of this topology, the principles of operation, theoretical analysis, and experimental waveforms are presented for a 1 kW prototype.
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Malik, Muhammad Zeeshan, Haoyong Chen, Muhammad Shahzad Nazir, et al. "A New Efficient Step-Up Boost Converter with CLD Cell for Electric Vehicle and New Energy Systems." Energies 13, no. 7 (2020): 1791. http://dx.doi.org/10.3390/en13071791.
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An increase in demand for renewable energy resources, energy storage technologies, and electric vehicles requires high-power level DC-DC converters. The DC-DC converter that is suitable for high-power conversion applications (i.e., resonant, full-bridge or the dual-active bridge) requires magnetic transformer coupling between input and output stage. However, transformer design in these converters remains a challenging problem, with several non-linear scaling issues that need to be simultaneously optimized to reduce losses and maintain acceptable performance. In this paper, a new transformer-less high step-up boost converter with a charge pump capacitorand capacitor-inductor-diode CLD cell is proposed using dynamic modeling. The experimental and simulation results of the proposed converter are carried out in a laboratory and through Matlab Simulink, where 10 V is given as an input voltage, and at the output, 100 V achieved in the proposed converter. A comparative analysis of the proposed converter has also been done with a conventional quadratic converter that has similar parameters. The results suggest that the proposed converter can obtain high voltage gain without operating at the maximum duty cycle and is more efficient than the conventional converter.
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MR., DEVENDRA P. JUMADE, and Nikhil Wadokar Prof. "COMPREHENSIVE STUDY OF HIGH FREQUENCY TRANSFORMER DESIGNING FOR MODIFIED FLYBACK CONVERTER." INTERNATIONAL JOURNAL OF INNOVATIONS IN ENGINEERING RESEARCH AND TECHNOLOGY 4, no. 11 (2017): 30–37. https://doi.org/10.5281/zenodo.1098518.
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The paper presents a special function improved Flyback converter is operate with better efficiency and compact size, which is prevail over most of the basic flyback converter downsides, and also keeping its inexpensiveness and lucidity. In certain, the converter permits the MOSFET OFF voltage to be less in amount and clamped to the input, thus healing the transformer leakage energy. As a result of effect, the duty cycle can be increase to unity, thus reducing the voltage stress across the output rectifier, and minimizing both the magnetizing inductance and the transformer bias current values. Moreover, to the auxiliary mosfet, the magnetizing current will negative, abolish the discontinuous conduction mode (DCM) of the basic Flyback and permits a smaller magnetizing inductance is to be selected. Besides, in contrast with the basic Flyback, the energy is supplied to the secondary side not only from the magnetizing inductance, but also from the introduced series capacitor, minimizing the transformer energy necessity. The improved converter makes also the soft-transitions possible for both mosfet. For all these reasons, as a more effective and compact size approximate, this topology shows better fulfillment in high power density inexpensive applications. This paper also presents practical design deliberation of high frequency transformers for flyback converters hiring High Frequency Transformer (HFT). In order to give insight to the reader, practical design examples are also provided.
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Mohammadzadeh Shahir, Farzad, Meysam Gheisarnejad, and Mohammad-Hassan Khooban. "A New Transformer-Less Structure for a Boost DC-DC Converter with Suitable Voltage Stress." Automation 2, no. 4 (2021): 220–37. http://dx.doi.org/10.3390/automation2040014.
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In this paper, a new structure is proposed for a boost dc–dc converter based on the voltage-lift (VL) technique. The main advantages of the proposed converter are its lack of transformer, simple structure, free and low input current ripple, high voltage gain capability by using an input source, suitable voltage stress on semiconductors and lower output capacitance. Herein, the analysis of the proposed converter operating and its elements voltage and current relations in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) are presented, and the voltage gain of each operating mode is individually calculated. Additionally, the critical inductance, current stress of switches, calculation of passive components’ values and efficiency are analyzed. In addition, the proposed converter is compared with other studied boost converters in terms of ideal voltage gain in the CCM and the number of active and passive components, maximum voltage stress on semiconductors, and situation of input current ripples. The correctness of the theoretical concepts is examined from the experimental results using the laboratory prototype.
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Mitra, Lopamudra, and Ullash Kumar Rout. "Single Switched Non-isolated High Gain Converter." International Journal of Power Electronics and Drive Systems (IJPEDS) 8, no. 1 (2017): 20. http://dx.doi.org/10.11591/ijpeds.v8.i1.pp20-30.
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<p>This paper presents a new single switched inductor- capacitor coupled transformer-less high gain DC-DC converter which can be used in renewable energy sources like PV, fuel cell in which the low DC output voltage is to be converted into high dc output voltage. With the varying low input voltages, the output of DC-DC converter remains same and does not change. A state space model of the converter is also presented in the paper. This constant output voltage is obtained by close loop control of converter using PID controller. High voltage gain of 10 is obtained without use of transformer. All the simulations are done in MATLAB-SIMULINK environment.</p>
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M.Kannan, G. Neelakrishnan,. "Transformer Less Boost DC-DC Converter with Photovoltaic Array." IOSR Journal of Engineering 3, no. 10 (2013): 30–37. http://dx.doi.org/10.9790/3021-031043037.
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Zunnurain, I. A., M. F. Hariz, S. M. Ilham, N. Kimpol, M. N. K. Anuar, and K. M. Yumi. "High Gain Transformer-less DC/AC Inverter for PV System." Journal of Physics: Conference Series 2129, no. 1 (2021): 012065. http://dx.doi.org/10.1088/1742-6596/2129/1/012065.
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Abstract Investigation interests on many scientific aspects of photovoltaic (PV) trans-former-less inverter system has improved over the past decade. Using step-up transformer or high frequency transformer in electrical system has made the entire system expensive and voluminous. There is alternative topology to replace the transformer by implementing DC/DC quadratic boost converter to expand the voltage from 12VDC to 325VDC from the photovoltaic (PV) solar and convert it to AC applying H-bridge inverter circuit. This method will replace the conventional method of bulky transformer into a lighter converter with the same performance. The circuit is simulated using Power Sim (PSIM) software to initiate the design and study the circuit capability. The experimental result will project the exact voltage in the range of 230VACrms . The harmonic profile of the inverter is studies and compared with the normal inverter configuration.
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Kirubhakaran, T., R. Viji, and S. Rajesh. "A Single Phase Transformer Less Grid Integrated Solar PV System with MPPT using Luo Converter." Journal of Alternative and Renewable Energy Sources 4, no. 3 (2018): 42–47. https://doi.org/10.5281/zenodo.2292301.
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The single phase transformer less grid with Luo converter is a type of a high-gain DC-DC converter that gives a positive output. Higher value of output voltage is obtained by using combination of inductors and capacitors by using a single switch voltage gain is two times of that provided by a boost converter. The two stages re-lift configuration gives higher value of output from a low input voltage. In this paper, the re- lift configuration of Luo converter in continuous conduction mode with MPPT is presented and the relevant expressions are derived. This single switch converter in single phase transformer-less grid with maximum power point tracking from solar pv system is suggested. Simulation results are presented to support the theoretical analysis.
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Galvão, Thiago, and Domingos Simonetti. "A Low-Power Setup Proposal for Power Transformer Loading Tests." Energies 12, no. 21 (2019): 4133. http://dx.doi.org/10.3390/en12214133.
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A setup for testing transformers under load through low power converter is presented in this paper. This setup is used for testing power transformers as it allows to verify their performance under operating conditions regarding aspects such as heating, voltage regulation, and mounting robustness. The main goal of the study is centered on replacing a full power Back-to-Back converter (1 pu) by a fractional power one (less than 0.1 pu). The converter, a Voltage Source Inverter (VSI), is a series connected between two equally sized transformers and controls the current flowing in the system. Load profile configurations set according to power factor, current harmonics, or even power level can be imposed to evaluate the performance of the Transformer Under Test (TUT) and the entire system. Theoretical analysis, and simulation results employing Matlab/Simulink platform, considering a typical transformer of a 75 kVA power distribution grid with 13.8 kV/220 V voltage are presented to corroborate the proposal. The required VSI power achieved in the simulations is a fraction of the total power of transformer under test, and the grid power consumed is also of small order justified by losses.
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Nazarpour, Dariush, Mohammadreza Farzinnia, and Hafez Nouhi. "Transformer‐less dynamic voltage restorer based on buck‐boost converter." IET Power Electronics 10, no. 13 (2017): 1767–77. http://dx.doi.org/10.1049/iet-pel.2016.0441.
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Yang, Zhi, Mustafa Tahir, Sideng Hu, Qiuyan Huang, and Haoqi Zhu. "Transformer Leakage Inductance Calculation Method with Experimental Validation for CLLLC Converter Topology." Energies 15, no. 18 (2022): 6801. http://dx.doi.org/10.3390/en15186801.
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Leakage inductance is one of the key parameters of a transformer, and it is often intentionally integrated into transformers. Rogowski’s equation is generally used for leakage inductance calculation; however, it is only applicable to concentric winding transformers where windings have the same height. Consequently, it has limited applications. This paper proposes a transformer leakage inductance calculation method using a double Fourier series. The limitation of Rogowski’s leakage inductance equation was analyzed in practical applications, and a new model for calculating the leakage inductance of a double-group-overlapping winding transformer was derived. Experimental prototypes of transformers were developed, and their simulation models were built in Ansys. The correctness of the proposed calculation method for transformer leakage inductance using a double Fourier series was verified by comparing the calculation results with the simulation and measured ones. A sensitivity analysis was also conducted by studying the variations in different parameters that might affect the leakage inductance value. The proposed calculation model gives an intuitive and simple method with less calculation and design effort while maintaining reasonable accuracy for leakage inductance calculation. In addition, the featured double Fourier series approach has a wider range of applications than Rogowski’s equation.
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Et. al., K. Girinath Babu,. "Three-Phase Three-Level Isolated DC-DC Soft Switching Converter For Solar Applications." INFORMATION TECHNOLOGY IN INDUSTRY 9, no. 2 (2021): 443–51. http://dx.doi.org/10.17762/itii.v9i2.368.
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Three-level isolated DC-DC converter is an attractive topology in high input voltage applications, which can provide the voltage stress of the power devices to only a half of the dc voltage and also reduce the size of dc filter requirement. But major limitations in the existing three level ZVS converter topologies are brought out with an increased inductance in the primary side and it required to provide complete ZVS of all primary devices down to light loads. By employing an external inductance in the primary of the transformer, total leakage inductance of the transformer increases which is required for realization of soft switching of the converter switches but there are some disadvantages of connecting external inductance in the primary of the transformer. To overcome all these drawbacks, the three-phase three-level isolated DC-DC soft switching converter has been proposed in order to reduce voltage and current stresses. This converter topology requires less number of control switches and operates with an asymmetrical duty cycle control. The proposed three level DC-DC converters provide two- level voltage waveform before dc output filter, which significantly reduce the size of dc output filter. The proposed work has been implemented using MATLAB/SIMULINK and the performance of the proposed converter is verified through simulation results.
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Arash, Akbari Bahareh, Majidi Majid, and Babaei Darvishi Farshid. "A transformer-less DC-DC converter for grid-connected PV systems using TSTS-ZSI voltage boost-buck technique." World Journal of Advanced Research and Reviews 23, no. 3 (2024): 3100–3109. https://doi.org/10.5281/zenodo.14993298.
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This research introduces an innovative design for a grid-connected photovoltaic (PV) system utilizing a transformer-less DC-DC converter. The converter is based on the TSTS-ZSI (Three-Switch Transformer-less Z-Source Inverter) voltage boost-buck technique, which enhances voltage regulation and energy transfer, making it ideal for micro-inverter applications. The primary goal of the study is to improve energy efficiency while ensuring seamless integration with the grid. The proposed system not only boosts voltage but also ensures efficient buck operation, leading to enhanced power injection into the grid under fluctuating conditions. By utilizing advanced control techniques, the converter minimizes power losses, reduces stress on the components, and maintains stability in a wide range of grid scenarios. Simulations performed using MATLAB/Simulink demonstrate that the converter delivers stable and efficient power with minimal energy loss. The results validate its effectiveness in small-scale grid-connected systems, achieving enhanced power management under various operating conditions. The converter's ability to operate efficiently without a transformer reduces magnetic losses and electromagnetic interference, making it a cost-effective and compact solution. The research presents a valuable contribution to the field of renewable energy integration, with its applications extending to both residential and commercial grid-connected PV systems.'
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Shrikant, P. Khadase, and N. A. Bodkhe Prof. "Improved Transformer Less Solar Inverter for Solar Grid Using Constants Power Generation." INTERNATIONAL JOURNAL OF ADVANCED INNOVATIVE TECHNOLOGY IN ENGINEERING (IJAITE) 7, no. 6 (2022): 1–5. https://doi.org/10.5281/zenodo.7275641.
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There are two main types of distributed solar power generation system stand-alone system and grid-connected system. In grid-connected system usually are equipped with additional transformer to transfer the energy from solar power to the grid. However, it has resulted in considerable cost in providing these systems. Therefore, in this research develops boost transformer less solar inverter system. The proposed system consists of a boost converter and transformer less inverter. Boost converter is used to increase the dc voltage yield by photovoltaic (PV) and delivered to the grid by mean of transformer less inverter. In order to maximize the power from PV, the proposed system is also designed with Maximum Power Point Tracking (MPPT) by changing the value of modulation index in the transformer less inverters. From the simulation results show that the system can work effectively in a variety condition such as light intensity changed and fluctuating in the grid voltage side. The algorithms utilized for MPPT are generalized algorithms and are easy to model or use as a code. The algorithms are written in m files of MATLAB and utilized in simulation.
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Mohammed Ali, Basim Khalid, Wisam Hasan Ali, and Noor Hameed Jalil. "Employing the Cascode Methods, A Transformer-Less High Voltage Gain Step-Up DC-DC Converter." Edison Journal for electrical and electronics engineering 2 (June 14, 2024): 27–34. http://dx.doi.org/10.62909/ejeee.2024.005.
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The goal of this research is to use the cascade approach to buck boost converters in order to produce high step-up voltage gain with a suitable duty ratio for an electric energy conversion system. Electronic equipment that demand electricity must convert AC voltage sources into DC power since they cannot be powered directly by the current electrical AC voltage. Significant voltage increases cannot be achieved by traditional boost converters because of the influence of power switches, parasitic resistive parts, and the diodes' reverse-recovery issue. The high voltage gains step-up (HVGSU) DC-DC converter, which combines two integrated buck-boost converters with a single switch, is proposed in this study. With the cascode technique, high voltage gain can be obtained without an extreme duty ratio; in this case, the switch's duty ratio is regulated by PWM technology. There is a thorough discussion of the suggested converter's equipment and modeling.
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Park, Young-un, Seung-yeol Oh, Je-suk Park, and Dae-kyong Kim. "Loss Analysis of High Frequency Transformers on a 3kW-Class DC-DC Converter using the Co-Simulation of Circuit and electromagnetic field analysis." International Journal of Engineering & Technology 7, no. 4.39 (2018): 667–70. http://dx.doi.org/10.14419/ijet.v7i4.39.25678.
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Background/Objectives: This study examined the loss analysis of a high frequency transformer using the thermal-electromagnetic coupled 3D-FEA considering practical converter circuit to improve the more accurate temperature analysis.Methods/Statistical analysis: The circuit used is a 3kW-class DC-DC converter. The circuit used was a 3kW-class DC-DC converter. FEA was used to analyze the electromagnetic field. The FEA modeling is based on the practical converter circuit and the measured current waveform.Findings: Thermal-electromagnetic coupled analysis was carried out to compare the results of the experiment and FEA models. The transformer flux density and thermal analysis of the stationary state was less than 0.38[T] and 35 [℃].Improvements/Applications: Most thermal studies for high frequency transformers are analytical and thermal equivalent circuit models. Therefore, thermal-electromagnetic coupled 3D-finite element analysis (FEA) considering the practical frequency excitations is required. Â
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Rosli, Eimi Diyana, Rijalul Fahmi bin Mustapa, and M. N. Hidayat. "Proposed on Transformer-Less Dynamic Voltage Restorer." Applied Mechanics and Materials 785 (August 2015): 409–13. http://dx.doi.org/10.4028/www.scientific.net/amm.785.409.
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Power delivered to consumer from utilities is susceptible to power quality problems. The most common power quality problems are voltage sag. Modern equipment nowadays are prone to problems associated with voltage sag. Such problems can be apprehended by several mitigation methods. This paper will discuss voltage sag mitigation method by eliminating the injection transformer in ordinary Dynamic Voltage Restorer (DVR) and applying Single Phase Matrix Converter (SPMC) in a single phase DVR topologies. The objective of this paper is to investigate the potential mitigation method without the injection transformer in the DVR topology. DVR circuit will be constructed and simulated using MATLAB/SIMULINK software. It is hoped that the result of this work will provide a simpler mitigation technique where existing DVR topology can be constructed with less component that provides unnecessary losses in the DVR itself.IndexTerms—Injection Transformer, DVR, SPMC, MATLAB/SIMULINK.
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Santos, Nelson, J. Fernando Silva, and Vasco Soares. "Control of Single-Phase Electrolytic Capacitor-Less Isolated Converter for DC Low Voltage Residential Networks." Electronics 9, no. 9 (2020): 1401. http://dx.doi.org/10.3390/electronics9091401.
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In recent years, there has been a desire to improve electricity generation and consumption, to reach sustainability. Technological solutions today allow a rational use of electricity with good overall performance. Traditionally, from production to distribution, electrical energy is AC-supported for compatibility reasons and easy voltage level transformation. However, nowadays most electric loads need DC power to work properly. A single high-efficiency central AC-DC power converter may be advantageous in eliminating several less efficient AC-DC embedded converters, distributed all over a residential area. This paper presents a new single-phase AC-DC converter using one active bridge (most isolated topologies are based on the dual active bridge concept) and a high-frequency isolation transformer with low-value non-electrolytic capacitors, together with its control system design. The converter can be introduced into future low-voltage DC microgrids for residential buildings, as an alternative to several embedded AC-DC converters. Non-linear control techniques (sliding mode control and the Lyapunov direct method) are employed to guarantee stability in the output DC low voltage with near unity power factor compensation in the AC grid. The designed converter and controllers were simulated using Matlab/Simulink and tested in a lab experimental prototype using digital signal processing (DSP) to evaluate system performance.
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Madasamy, P., Rajesh Verma, A. Rameshbabu, et al. "Neutral Point Clamped Transformer-Less Multilevel Converter for Grid-Connected Photovoltaic System." Electronics 10, no. 8 (2021): 977. http://dx.doi.org/10.3390/electronics10080977.
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Transformer-less (TL) inverter topologies have elicited further special treatment in photo-voltaic (PV) power system as they provide high efficiency and low cost. Neutral point clamped (NPC) multilevel-inverter (MLI) topologies-based transformer-less are being immensely used in grid-connected medium-voltage high-power claims. Unfortunately, these topologies such as NPC-MLI, full-bridge inverter with DC bypass (FB-DCBP) suffer from the shoot-through problem on the bridge legs, which affect the reliability of the implementation. Based on the previous above credits, a T type neutral point clamped (TNP)—MLI (TNP-MLI) with transformer-less topology called TL-TNP-MLI is presented to be an alternate which can be suitable in the grid-connected PV power generation systems. The suggested TL-TNP-MLI topologies free from inverter bridge legs shoot-through burden, switching frequency common-mode current (CMC), and leakage current. The control system of the grid interface with hysteresis current control (HCC) strategy is proposed. The effectiveness of the proposed PV connected transformer-less TNP-MLI topology with different grid and PV scenario has been verified through the MATLAB/Simulink simulation model and field-programmable gate area (FPGA)-based experimental results for a 1.5 kW system.
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Ramya, K. C., and V. Jegathesan. "Design and analysis of isolated and non-isolated bidirectional converter for high voltage applications." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 35, no. 5 (2016): 1592–603. http://dx.doi.org/10.1108/compel-04-2016-0162.
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Purpose A DC-DC converter plays a major role in many applications such as fuel cell, hybrid electric vehicle, renewable energy system, etc. Among these converters, the bidirectional DC-DC fly-back converters are more attractive because of their simple structure and easy control. However, the power devices present in this converter are subjected to high-voltage stresses due to the leakage inductor energy of the transformer. In order to recycle the leakage inductor energy and to minimise the voltage stress on the power devices, the purpose of this paper is to focus on the transformer less bidirectional DC-DC converter with high efficiency. Design/methodology/approach In order to reduce the switching loss, a few passive elements are added. The auxiliary circuit consists of a resonant inductor and resonant capacitors. This auxiliary circuit affords zero voltage switching function and cancels out the ripple component present in the main inductor current irrespective of the power flow direction. Findings In this work three topologies of bidirectional converters for BLDC motor are investigated and are compared in terms of mechanical power output and THD. Originality/value The paper presents enhanced versions of the converters.
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Mohd, Haris, Asim Mohammed, and Tariq Mohd. "Transformer-less DC-DC Converter with Low Duty Ratio Using a Single Switch and Quasi Impedance Based Network." Indian Journal of Science and Technology 17, no. 4 (2024): 359–67. https://doi.org/10.17485/IJST/v17i4.3121.
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Abstract <strong>Objective:</strong> Transformer-less DC-DC converter suitable for low-power applications, with a high voltage gain. With fewer elements, this suggested converter may generate a higher gain voltage at a lower duty ratio. <strong>Method:</strong> A transformer-less quasi-Z-source DC-DC converter with gain is introduced and examined. To boost the load voltage, the topology makes use of both the switched capacitor and active switched-inductor structure based on the quasi-Z-impedance network. The theoretical outcomes and the converter's functionality are verified by the simulation, which is run using the PLECS software program. <strong>Findings:</strong> The benefits of the conventional Z-source boost converter, including fewer voltage stress, constant input current, and common ground, are still present in the suggested converter. Additionally, at a relative duty ratio of 0.3, the gain is greatly increased by around 10 times. Each power switch's voltage stress is also significantly decreased. A detailed discussion is held on the steady-state operation. <strong>Novelty:</strong> A novel architecture with higher voltage gain at a decreased duty ratio is presented in this work. The network of inductors and capacitors typically used to raise the dc-dc converter's output voltage. The suggested topology raises the output voltage by using just one switch and switched capacitor and switched inductor network. <strong>Keywords:</strong> Transformer­less converter, duty cycle, voltage gain, common ground, single switch
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Shulhin, A. L., and D. A. Losikhin. "The use of a full-wave amplifying rectifier without diodes on operational amplifiers in an automated testing system on a tensile testing machine." Computer Modeling: Analysis, Control, Optimization 7, no. 1 (2020): 70–74. http://dx.doi.org/10.32434/2521-6406-2020-1-7-70-74.
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The article discusses the problem of transformation of measuring signal of differential transformer converter of universal testing machines for further processing by microprocessor controller. In order to automate the testing process, it is necessary to collect, process and transmit the measured data to an automated workplace using a microprocessor controller. Due to the fact that usually the secondary windings of the differential transformer converters produce an alternating voltage of very small magnitude, such a measurement signal cannot be processed with the help of modern microprocessor controllers without conversion. Since the analog-to-digital converter of the microprocessor controller cannot operate with alternating voltage, it becomes necessary to rectify and amplify the measuring signal. For low voltages (less than 0.6 V), the use of conventional resistor-diode rectifiers becomes impossible and there is a need for other methods of rectifying alternating current. It is proposed to use full-wave active rectifiers without diodes on operational amplifiers for conversion of the measuring signal of differential transformer converters, the main disadvantages of diode rectifiers and advantages of rectifiers on operational amplifiers are considered. The biggest advantage of a rectifier proposed for use in an automated testing system is the ability to simultaneously rectify and amplify the measurement signal with the required precision, allowing it to be processed by most modern microprocessor controllers. For the first time, an automated testing system on a tensile machine was developed using an active full-wave voltage rectifier on operational amplifiers without the use of diodes. The circuit shown in the article makes it possible to convert the signal of a differential transformer converter for further processing using the Arduino microcontroller platform. An amplifying active full-wave voltage rectifier without diodes on operational amplifiers can be used to modernize testing or measurement equipment containing a differential transformer transducer of a measuring signal. The developed electrical circuit of the rectifier was applied to automate the process of testing on the breaking machine of model P-0.5. Keywords: differential transformer converter, operational amplifier, rectifier, measuring signal converter, tensile testing machine, automated test system.
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Rajalakshmi, P. "A Dual-transformer DC–DC with Variable frequency modulation Technique." Journal of Energy Engineering and Thermodynamics, no. 23 (May 30, 2022): 15–23. http://dx.doi.org/10.55529/jeet.23.15.23.
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For renewable power production systems to use less energy overall, power converters with improved efficiency over a wider load range are crucial. We introduce an unique dual-transformer DC-DC converter with many resonant components. With the right choice of resonance parameters, the converter can achieve a broad DC voltage gain range thanks to several resonance features. More resonance frequencies are included in the proposed converter as well, which will allow the load to receive more of the tertiary active power. Diodes achieve soft-switching or quasi-soft-switching during both the on and off periods, and all power switches are capable of on-soft switching. The proposed and analysis of variable frequency modulation (VFM) are achieved. By providing soft switching throughout the whole load range, the suggested modulation approach can lower switching losses. Additionally, the center-tapped bridge implementation of the synchronous rectifier further reduces conduction losses while the proposed modulation technique ensures soft switching of all devices. We installed a 500W prototype in the laboratory to confirm the theoretical analysis. According to the findings of the experiments, the suggested converter can maintain a relatively high efficiency (95%) throughout a wide load range. Starting with 300W, the highest efficiency is 95.4%.
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Rajalakshmi, P. "A Dual-transformer DC–DC with Variable frequency modulation Technique." Journal of Image Processing and Intelligent Remote Sensing, no. 12 (November 25, 2021): 8–16. http://dx.doi.org/10.55529/jipirs.12.8.16.
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For renewable power production systems to use less energy overall, power converters with improved efficiency over a wider load range are crucial. We introduce an unique dual-transformer DC-DC converter with many resonant components. With the right choice of resonance parameters, the converter can achieve a broad DC voltage gain range thanks to several resonance features. More resonance frequencies are included in the proposed converter as well, which will allow the load to receive more of the tertiary active power. Diodes achieve soft-switching or quasi-soft-switching during both the on and off periods, and all power switches are capable of on-soft switching. The proposed and analysis of variable frequency modulation (VFM) are achieved. By providing soft switching throughout the whole load range, the suggested modulation approach can lower switching losses. Additionally, the center-tapped bridge implementation of the synchronous rectifier further reduces conduction losses while the proposed modulation technique ensures soft switching of all devices. We installed a 500W prototype in the laboratory to confirm the theoretical analysis. According to the findings of the experiments, the suggested converter can maintain a relatively high efficiency (95%) throughout a wide load range. Starting with 300W, the highest efficiency is 95.4%.
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Abdollahi, Rohollah. "Study of delta/polygon-connected transformer-based 36-pulse ac-dc converter for power quality improvement." Archives of Electrical Engineering 61, no. 2 (2012): 277–92. http://dx.doi.org/10.2478/v10171-012-0023-1.
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Study of delta/polygon-connected transformer-based 36-pulse ac-dc converter for power quality improvementDesign of a delta/polygon-connected autotransformer based 36-pulse ac-dc converter is presented in this paper. The 36-pulse topology is obtained via two paralleled eighteen-pulse ac-dc converters each of them consisting of a nine-phase (nine-leg) diode bridge rectifier. For independent operation of paralleled diode-bridge rectifiers, two interphase transformers (IPT) is designed and implemented. A transformer is designed to supply the rectifier. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. The proposed structure has been implemented and simulated using Matlab/Simulink software under different load conditions. Simulation results confirmed the significant improvement of the power quality indices (consistent with the IEEE-519 standard requirements) at the point of common coupling. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 4% for the proposed topology at variable loads.
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Ragonese, Egidio, Nunzio Spina, Alessandro Parisi, and Giuseppe Palmisano. "An Experimental Comparison of Galvanically Isolated DC-DC Converters: Isolation Technology and Integration Approach." Electronics 10, no. 10 (2021): 1186. http://dx.doi.org/10.3390/electronics10101186.
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This paper reviews state-of-the-art approaches for galvanically isolated DC-DC converters based on radio frequency (RF) micro-transformer coupling. Isolation technology, integration level and fabrication issues are analyzed to highlight the pros and cons of fully integrated (i.e., two chips) and multichip systems-in-package (SiP) implementations. Specifically, two different basic isolation technologies are compared, which exploit thick-oxide integrated and polyimide standalone transformers, respectively. To this aim, previously available results achieved on a fully integrated isolation technology (i.e., thick-oxide integrated transformer) are compared with the experimental performance of a DC-DC converter for 20-V gate driver applications, specifically designed and implemented by exploiting a stand-alone polyimide transformer. The comparison highlights that similar performance in terms of power efficiency can be achieved at lower output power levels (i.e., about 200 mW), while the fully integrated approach is more effective at higher power levels with a better power density. On the other hand, the stand-alone polyimide transformer approach allows higher technology flexibility for the active circuitry while being less expensive and suitable for reinforced isolation.
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Sujitha, C., S. Ravi, Bakary Diarra, and Joseph Chuma. "Transformer Less Voltage Quadrupler Based DC-DC Converter with Coupled Inductor and PI Filter for Increased Voltage Gain and Efficienc." International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no. 4 (2016): 1023. http://dx.doi.org/10.11591/ijpeds.v7.i4.pp1023-1030.
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<p>In this paper a voltage quadrupler dc-dc converter with coupled inductor and π filter is presented. The use of the coupled inductor reduces the high leakage inductance which is present in a transformer enabled converter. The output ripples in the converter is reduced by providing a π filter. The interleaved voltage quadrupler is used in this system in order to boost the output voltage. The voltage multiplier improves the output voltage gain. The main advantage of this system is more voltage gain when compared with the transformer eneabled circuit and the overall efficiency of the system is improved. The circuit is simple to control. As a final point of this research, the simulation and the hardware investigational results are presented to demonstrate the effectiveness of this proposed converter.</p>
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M, Vinil, Ramya G, Moovendan M, and Ajay Daniel J. "Reactive Power Injection to Grid Using Transformer-Less MOSFET Based Single Phase Inverter Using PV to Achieve High Efficiency." ECS Transactions 107, no. 1 (2022): 5305–16. http://dx.doi.org/10.1149/10701.5305ecst.
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The transformer-less inverter has an increasing demand due to its low cost, high efficiency, and reliability. The elimination of transformers from grid connected PV enables to create the leakage currents across stray capacitance, which is connected between PV and the ground. To overcome this disadvantageous issue, the topology used is a single step conversion process of directly connecting coupled inductor to the grid. The efficiency and the quality of AC output current is improved by implementation of high frequency PWM switching commutation to the converter. The proposed system is focused to inject reactive power to the grid, changing the controlling techniques used for the Gate Pulse input, and reducing the number of switches, passive elements, and harmonics. It has an overall efficiency of 98.04%, higher than those of existing converters.
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Eya, Candidus U., Ayodeji Olalekan Salau, and Stephen Ejiofor Oti. "High Performance DC-to-AC Converter Using Snubberless H-Bridge Power Switches and an Improved DC-to-DC Converter." International Journal of Circuits, Systems and Signal Processing 15 (April 8, 2021): 315–33. http://dx.doi.org/10.46300/9106.2021.15.36.
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This paper presents the analysis, modeling, simulation, and implementation of a high performance DC-to-AC (DC-AC) converter. The system comprises of a combination of DC power source, stress less DC-to-DC (DC-DC) voltage converter, two snubberless power switches, and control unit. The system is portable, has a two-stage input voltage transformation and amplification with no transformer and occupies less space unlike the classical two-stage inverter systems. In addition, the system produces a constant DC boosted voltage with less stress on both the source and DC storage capacitor which are not found in conventional converters. The proposed power electronic converter system produced the following results: pure sine voltage and current waveforms, total harmonic distortion (THD) of 4.294%, power output of 5740W, efficiency of 98.9%, power loss of 60W and fast dynamic response. The target areas of applications of the proposed converter are in medium and small scale industries.
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Candidus, U. Eya, C. Ejiogu E, and O. Omeje Crescent. "Hybrid Powered Converter with Relay-Less Automatic Changeover." Journal of Alternative and Renewable Energy Sources 5, no. 2 (2019): 17–21. https://doi.org/10.5281/zenodo.3368064.
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This paper presents a hybrid powered converter with relay-less automatic changeover. No sensor circuit is needed for the power sources to be interchanged to unlike the conventional automatic changeover. The proposed system has nothing to with relay system. The two power sources are the solar panels and the battery bank. The automatic changeover system is based on the voltage disparity between the two power sources. It is realized by combination of solar panels, bidirectional converter and load. The advantages of the proposed systems are: (i) It is light in weight; (ii) It has minimum power losses; (iii) It is very cheap and (iv) It is transformer-less system. It is applied basically in homes and medium scale industries.
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Arash Akbari Bahareh, Majid Majidi, and Farshid Babaei Darvishi. "A transformer-less DC-DC converter for grid-connected PV systems using TSTS-ZSI voltage boost-buck technique." World Journal of Advanced Research and Reviews 23, no. 3 (2024): 3100–3109. http://dx.doi.org/10.30574/wjarr.2024.23.3.2896.
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This research introduces an innovative design for a grid-connected photovoltaic (PV) system utilizing a transformer-less DC-DC converter. The converter is based on the TSTS-ZSI (Three-Switch Transformer-less Z-Source Inverter) voltage boost-buck technique, which enhances voltage regulation and energy transfer, making it ideal for micro-inverter applications. The primary goal of the study is to improve energy efficiency while ensuring seamless integration with the grid. The proposed system not only boosts voltage but also ensures efficient buck operation, leading to enhanced power injection into the grid under fluctuating conditions. By utilizing advanced control techniques, the converter minimizes power losses, reduces stress on the components, and maintains stability in a wide range of grid scenarios. Simulations performed using MATLAB/Simulink demonstrate that the converter delivers stable and efficient power with minimal energy loss. The results validate its effectiveness in small-scale grid-connected systems, achieving enhanced power management under various operating conditions. The converter's ability to operate efficiently without a transformer reduces magnetic losses and electromagnetic interference, making it a cost-effective and compact solution. The research presents a valuable contribution to the field of renewable energy integration, with its applications extending to both residential and commercial grid-connected PV systems.'
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Shayeghi, Hossein, Saeed Pourjafar, Seyed Majid Hashemzadeh, and Farzad Sedaghati. "Presenting of the Magnetic Coupling-Based Transformer-Less High Step-Up DC-DC Converter for Renewable Energy Applications." International Transactions on Electrical Energy Systems 2022 (March 14, 2022): 1–15. http://dx.doi.org/10.1155/2022/3141119.
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This study presents a new high step-up converter based on the voltage multiplier cell and coupled inductor for renewable energy applications such as fuel cell and photovoltaic power systems. This converter achieves a high voltage conversion ratio using a coupled inductor and voltage multiplier cell (VMC). The voltage multiplier cell acts as a passive clamp circuit and reduces the maximum voltage across the power switch. The suggested topology has only one power switch in its structure, which leads to low cost and volume. The other benefits of the proposed structure are low components count, low input current ripple, low voltage stress throughout the semiconductors, high efficiency, zero-current switching (ZCS), and zero-voltage switching (ZVS) of diodes. Besides, due to the soft-switching condition of the diodes, the reverse recovery problem can be decreased. To show the effectiveness of the suggested topology, operation survey, steady-state analysis, and efficiency calculation are provided. Additionally, the comparison study with other similar converters illustrates the superiority of the proposed structure. Finally, an experimental prototype with 150 W rated power, 50 kHz switching frequency, and 24 V input voltage is implemented to prove the mathematical analysis and effectiveness of the proposed DC-DC converter.
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Liu, Jinshuo, Wenhua Xu, and Tao Xu. "A Highly Accurate Mathematical Model for Analyzing Modular Multilevel Converters in Transformer-Less Applications." Symmetry 14, no. 12 (2022): 2498. http://dx.doi.org/10.3390/sym14122498.
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Transformer-less connection schemes can provide a feasible solution for lowering the economic cost, occupied space, and device weight of modular multilevel converter (MMC) systems. However, due to the reduction in the converter transformer, the current flow loop is changed; as a result, the existing MMC model is not suitable. In this paper, the ac- and dc-side equivalent circuit models of the MMC system using a transformer-less connection scheme are established in both a–b–c stationary and d–q rotating coordinate systems. Then, a highly accurate mathematical analysis model is proposed, in which the interactions among the electrical quantities can be fully seen. The mathematical model is established in the time domain, and hence the amplitude and phase angle of every harmonic component in each quantity can be directly obtained. The proposed model is verified under various typical situations by comparing the calculated values with the actual waveforms. The comparison results prove that the calculation error is small enough to be negligible. The mathematical model in this paper can provide a powerful tool in terms of the performance analysis and the main circuit parameter design for MMCs in transformer-less applications.
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Priyadarshi, Neeraj, Mahajan Sagar Bhaskar, Farooque Azam, et al. "Performance Evaluation of Solar-PV-Based Non-Isolated Switched-Inductor and Switched-Capacitor High-Step-Up Cuk Converter." Electronics 11, no. 9 (2022): 1381. http://dx.doi.org/10.3390/electronics11091381.
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Solar photovoltaic (PV) is the most promising renewable energy source available on Earth. Three topologies based on a switched-inductor capacitor and non-isolated high-step-up Cuk converter have been proposed for solar PV. These topologies of the Cuk converter have higher boosting ability than conventional Cuk and boost converters and can reduce the voltage stress of the main switch. A small voltage rating and on-state resistance can give higher efficiency of the converter. The voltage boosting ability of all three topologies was compared to each other and with a conventional Cuk converter. The boosting capability of the third converter was 11 times at 0.75 duty cycle with a solar PV source. These converters do not use a coupled inductor and transformer, which leads to less volume, reducing coupling/core saturation loss, and thus the cost of the converter. A solar PV system of 12 volts was used for boosting with these converters for analysis of the feasibility of use with renewables. The three topologies of the switched-inductor and switched-capacitor (SLSC) Cuk converter were designed and simulated in MATLAB/Simulink to evaluate their effectiveness.
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Priyadarshi, Neeraj, Mahajan Sagar Bhaskar, Farooque Azam, et al. "Performance Evaluation of Solar-PV-Based Non-Isolated Switched-Inductor and Switched-Capacitor High-Step-Up Cuk Converter." Electronics 11, no. 9 (2022): 1381. http://dx.doi.org/10.3390/electronics11091381.
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Solar photovoltaic (PV) is the most promising renewable energy source available on Earth. Three topologies based on a switched-inductor capacitor and non-isolated high-step-up Cuk converter have been proposed for solar PV. These topologies of the Cuk converter have higher boosting ability than conventional Cuk and boost converters and can reduce the voltage stress of the main switch. A small voltage rating and on-state resistance can give higher efficiency of the converter. The voltage boosting ability of all three topologies was compared to each other and with a conventional Cuk converter. The boosting capability of the third converter was 11 times at 0.75 duty cycle with a solar PV source. These converters do not use a coupled inductor and transformer, which leads to less volume, reducing coupling/core saturation loss, and thus the cost of the converter. A solar PV system of 12 volts was used for boosting with these converters for analysis of the feasibility of use with renewables. The three topologies of the switched-inductor and switched-capacitor (SLSC) Cuk converter were designed and simulated in MATLAB/Simulink to evaluate their effectiveness.
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Nagi Reddy, B., G. Vinay Kumar, B. Vinay Kumar, B. Jhansi, B. Sandeep, and K. Sarada. "Fuel Cell Based Ultra-Voltage Gain Boost Converter for Electric Vehicle Applications." Transactions on Energy Systems and Engineering Applications 4, no. 1 (2023): 68–90. http://dx.doi.org/10.32397/tesea.vol4.n1.519.
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The proposed fuel cell-based ultra-voltage gain boost converter offers an alternative to transformer-based topologies for achieving high voltage gain. While transformers can achieve high voltage gains, they come with drawbacks such as high cost, design complexity, and increased weight. In this article, a switched inductor circuit is introduced as an alternative solution to achieve high voltage gain. This circuit enhances overall system performance by reducing size, weight, and cost. Operating in a transformer-less topology, the converter boosts voltage levels while ensuring low voltage stress on the switching devices. The suggested design enables larger voltage gain values even at low duty ratios. The output of the fundamental boost converter serves as the input for the switched inductor circuit, effectively boosting the voltage level and supplying more voltage to the output side. This converter is particularly suitable for applications requiring ultra-voltage gain in electric vehicles, which offer reduced pollution compared to internal combustion engines. Moreover, the utilization of this topology reduces space requirements. The article presents a thorough investigation of the steady state operation in continuous conduction mode, and theoretical verification and MATLAB simulations demonstrate the performance and operation of the proposed converter.
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Kwon, Jaean, and Rae-Young Kim. "High Power Density, High-Voltage Parallel Resonant Converter Using Parasitic Capacitance on the Secondary Side of a Transformer." Electronics 10, no. 14 (2021): 1736. http://dx.doi.org/10.3390/electronics10141736.
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High-voltage DC power supplies are used in several applications, including X-ray, plasma, electrostatic precipitator, and capacitor charging. However, such a high-voltage power supply has problems, such as a decrease in reliability, owing to an increase in output ripple voltage, and a decrease in power density, owing to an increase in volume. Therefore, this study proposes a method for improving the power density of a parallel resonant converter using the parasitic capacitor of the secondary side of the transformer. Due to the fact that high-voltage power supplies have many turns on the secondary side, a significant number of parasitic capacitors are generated. In addition, in the case of a parallel resonant converter, because the transformer and the primary resonant capacitor are connected in parallel, the parasitic capacitor component generated on the secondary side of the transformer can be equalized and used. A parallel cap-less resonant converter structure developed using the parasitic components of such transformers is proposed. Primary side and secondary side equivalent model analyses are conducted in order to derive new equations and gain waveforms. Finally, the validity of the proposed structure is verified experimentally.
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Chang, Chien-Hsuan, and Yi-Fan Chen. "A Transformer-Less Buck-Boost Grid-Tied Inverter with Low Leakage-Current and High Voltage-Gain." Applied Sciences 11, no. 8 (2021): 3625. http://dx.doi.org/10.3390/app11083625.
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To improve the efficiency of photovoltaic (PV) grid-tied systems and simplify the circuit structure, many pseudo DC-link inverters have been proposed by combining a sinusoidal pulse-width modulation (SPWM) controlled buck-boost converter and a low-frequency polarity unfolder. However, due to the non-ideal characteristics of power diodes, the voltage-gain of a buck-boost converter is limited. To meet the needs of grid-connected systems with low input voltage and 220 Vrms utility, this paper uses two two-switch buck-boost converters with coupled inductors to develop a transformer-less buck-boost grid-tied inverter with low leakage-current and high voltage-gain. The proposed inverter is charging on the primary side of the coupled inductor and discharging in series on the primary side and the secondary side so that the voltage-gain can be greatly increased. Furthermore, the utility line can be connected to the negative end of the PV array to suppress leakage current, and the unfolding circuit can be simplified to reduce the conduction losses. High-frequency switching is only performed in one metal-oxide-semiconductor field-effect transistor (MOSFET) in each mode, which can effectively improve conversion efficiency. A prototype was implemented to obtain experimental results and to prove the validity of the proposed circuit structure.
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Sindhuja, R., and S. Padma. "Bipolar DC output fed grounded DC-AC converter for photovoltaic application." Electrical Engineering & Electromechanics, no. 2 (March 5, 2023): 57–62. http://dx.doi.org/10.20998/2074-272x.2023.2.09.
Full textAbstract:
Introduction. In recent years the usage of electricity has increased tremendously as the electrical needs and loads got increased. Hence the researchers focused on the electricity generation from renewable sources in order to promote sustainable green environment. Owing to the lesser cost and more reliable high efficiency system with reduced use of equipments became prominent for the grid connected photovoltaic single phase systems. The novelty of this proposed converters are to reduce total power loss and to analyze the performance of the converter under various modulation index and to have lesser harmonics using sinusoidal pulse width modulation technique for both T-type and F-type inverter. Interest of the work is to merge two DC-DC converters which have same output voltage in order to have transformer less utilization of power. This has given pathway to develop a new DC-DC converter network by merging the common input nodes of CUK and SEPIC converter. Purpose. This similar structure of both converters made it easy to combine the input stages of and to get bipolar output. Methods. Here we can get bipolar output without the utilization of transformer which minimizes the overall size of the proposed system. In this paper, a combined CUK-SEPIC based grid connected transformerless inverter for photovoltaic application is suggested. Results. The suggested converter is simulated using MATLAB and the results were discussed. Further the circuit is extended with a 1 kW F-type inverter to demonstrate grid connection of the converter. Practical value. This converter can be implemented for photovoltaic applications for obtaining the bipolar DC output from the DC source.