Improved Controller and Design Method for Grid-Connected Three-Phase Differential SEPIC Inverter

Shawky, Ahmed; Takeshita, Toru; Sayed, Mahmoud A.; Aly, Mokhtar; Ahmed, Emad M.

doi:10.1109/access.2021.3072489

Cited by 15 publications

(9 citation statements)

References 52 publications

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“…Also, differential based three-phase inverters usually offer a low operating efficiency compared with Dual-Active-Bridge based systems due to the existence of low-order harmonics and the voltage stress, which results from the voltage boosting property in a single-stage operation. According to previous literatures, average efficiency of differential-based three-phase inverters based on (Cuk, SEPIC,....) is between (86-91%) [6], [33], [37]. On the other hand, grid-connected three-phase DC-AC inverters based on matrix or dual-activebridge converters usually exhibit efficiency in the range of (94% to 97%) depending on the utilized switch type (i.e.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, a conventional PI-based grid-currents control loop is used for grid currents regulation [32]. In [33], the authors proposed three-phase SEPIC differential inverter for PV applications. However, the presented structure requires increased number of passive elements that enlarges converter size and footprint and increases its cost.…”

Section: Introductionmentioning

confidence: 99%

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Three-Phase Single-Carrier PWM Inverter for Isolated Grid-Tied PV Applications

et al. 2022

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Owing to their dependency of weather conditions, distributed generation systems are integrated with utility grid through power converters. This paper proposes an isolated three-phase based flyback-inverter (TBFBI) that can be used as a central-type inverter for grid-tied PV applications. To alleviate DC-current ripples at the input side, the proposed inverter utilizes only a single LC-filter with small passive elements size, which reduces the system footprint and cost. Mathematical modeling of the TBFBI in addition to its control technique is presented in detail. Compared with other differential based converters, the proposed control technique is designed considering the least number of control loops and required sensors by using terminal voltage estimation strategy. Continuous-modulation-scheme (CMS) combined with static-linearization strategy (SLS) is utilized to diminish the low-order odd harmonics. In addition, harmonic compensation technique is utilized to eliminate negative-sequence harmonic component (NSHC) from the grid-injected currents. Also, identical three single-phase high-frequency transformers (HFTs) are designed based-on ferrite and nanocrystalline cores to compare the inverter operating efficiency. The TBFBI is experimentally validated via laboratory prototype-based 200 V, 1.6 kW, and switching frequency of 50 kHz. Experimental results of 1.6 kW power flow show that THD of the grid current is 3.95%, peak-to-peak current ripple at the input DC-side is 2.1% of the average DC input current that matches the IEEE-1547 standards for grid-tied PV applications.INDEX TERMS DC-AC grid-tied converter, flyback-inverter, high frequency transformer (HFT), harmonic compensation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Three-Phase Single-Carrier PWM Inverter for Isolated Grid-Tied PV Applications

et al. 2022

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“…For example, a phase-controlled i-AFE based on three 2×2 matrix converters results in the use of 36 active semiconductors [147], [148]. To reduce the number of components in phase-controlled solutions, SEPIC-based [149], [150], and cascaded full-bridge converters [151]- [153] were proposed.…”

Section: Phase-controlled Single-stage I-afementioning

confidence: 99%

Grid Integration of DC Buildings: Standards, Requirements and Power Converter Topologies

Carvalho

Blinov

Chub

et al. 2022

IEEE Open J. Power Electron.

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Residential dc microgrids and nanogrids are the emerging technology that is aimed to promote the transition to energy-efficient buildings and provide simple, highly flexible integration of renewables, storages, and loads. At the same time, the mass acceptance of dc buildings is slowed down by the relative immaturity of the dc technology, lack of standardization and general awareness about its potential. Additional efforts from multiple directions are necessary to promote this technology and increase its market attractiveness. In the near-term, it is highly likely that the dc buildings will be connected to the conventional ac distribution grid by a front-end ac-dc converter that provides all the necessary protection and desired functionality. At the same time, the corresponding requirements for this converter have not been yet consolidated. To address this, present paper focuses on various aspects of the integration of dc buildings and includes analysis of related standards, directives, operational and compatibility requirements as well as classification of voltage levels. In addition, power converter configurations and modulation methods are analyzed and compared. A classification of topologies that can provide the required functionality for the This article has been accepted for publication in IEEE Open Journal of Power Electronics.

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“…Alternatively, an impressive inverter topology based on buck, boost, or buck-boost DC-DC modules is presented and known as differential inverter. It shows noteworthy success in the power electronics industry due to their modularity, single-stage, and bidirectional power conversion with step-up/down ability [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29]. Further, unlike the abovementioned single-stage inverter topologies, differential inverters provide galvanic isolation between source and load by integrating small HFT.…”

Section: Introductionmentioning

confidence: 99%

Differential Inverters: A General Design Procedure Integrating a Novel Power Losses Modeling Approach for Utilized DC-DC Modules at Different Modulation Schemes

Shawky

Aly²,

Rodríguez³

2023

IEEE Access

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Differential inverters develop the PWM of internal DC-DC modules by correlating fundamental frequency of load with high switching frequency to maintain inherent characteristic operation and achieve pure higher/lower AC output voltage with smaller size. However, no generalized design method applicable for many DC-DC modules topologies has been demonstrated up till now, to realize efficient differential inverter with accurate power loss prediction. Consequently, a generic design process utilizing one parameter (modulation index gain) as well as new power losses modeling for all elements, such as switching devices, inductors, capacitors, and extra, are proposed in this paper. Novel decoupling between both operational frequencies through a two-stage calculation algorithm is the main attractive feature where, all losses are calculated based on the switching frequency of DC-DC modules then all losses are averaged accordingly over fundamental frequency. Doing this obtains RMS currents in terms of actual duty cycle and other parameters without adding complex mathematics at various PWM schemes, such as SVMS, CMS and DMS. The proposed work is simultaneously employed for many DC-DC modules topologies and verified in simulation and experiments using 0.7kW 50kHz isolated SEPIC-based DC-DC modules, as a case study. The error into actual duty cycle is decreased from 5.19% to 2.47% in the case of CMS at different power ratings. Further, it is reduced to 2.64% and 1.86% for SVMS and DMS, respectively. Finally, smart foretelling of power loss in each element of differential inverter is considered crucial for future efficiency improvement.

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Improved Controller and Design Method for Grid-Connected Three-Phase Differential SEPIC Inverter

Cited by 15 publications

References 52 publications

Three-Phase Single-Carrier PWM Inverter for Isolated Grid-Tied PV Applications

Three-Phase Single-Carrier PWM Inverter for Isolated Grid-Tied PV Applications

Grid Integration of DC Buildings: Standards, Requirements and Power Converter Topologies

Differential Inverters: A General Design Procedure Integrating a Novel Power Losses Modeling Approach for Utilized DC-DC Modules at Different Modulation Schemes

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