A 5-level high efficiency low cost Hybrid Neutral Point Clamped transformerless inverter for grid connected photovoltaic application

Kadam, Abhijit; Shukla, Anshuman

doi:10.1109/apec.2018.8341558

Cited by 3 publications

(4 citation statements)

References 10 publications

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“…The most important requirements stated in the previous section (i.e., efficiency higher than 95%, and THD of the output signals lower than 5%) can be achieved, and particularly with the NPC and FC topologies [34], [39]. Kadam et al have particularly highlighted that 5-level NPC topology requires a high number of semiconductor devices (i.e., 8 power switches to be controlled, and 4 diodes), and a high number of mandatory capacitors (i.e., 4 capacitors) for the required function [34]. Regarding the FC topology, Lei et al have highlighted that it is necessary to increase the number of levels (i.e., 7-level inverter structure), the number of semiconductor devices (i.e., 16 power switches to be controlled), and the number of mandatory capacitors (i.e., 6 capacitors) to meet the same performances as described above [39].…”

Section: Limitations Of Existing Dc-ac Topologiesmentioning

confidence: 94%

“…Table 1 sums up the main performances of such topologies reported in the literature [34][35][36][37][38][39][40][41][42]. The most important requirements stated in the previous section (i.e., efficiency higher than 95%, and THD of the output signals lower than 5%) can be achieved, and particularly with the NPC and FC topologies [34], [39]. Kadam et al have particularly highlighted that 5-level NPC topology requires a high number of semiconductor devices (i.e., 8 power switches to be controlled, and 4 diodes), and a high number of mandatory capacitors (i.e., 4 capacitors) for the required function [34].…”

Section: Limitations Of Existing Dc-ac Topologiesmentioning

confidence: 99%

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An Innovative Bidirectional DC-AC Converter to Improve Power Quality in a Grid-Connected Microgrid

Bissey¹,

Jacques²,

Reymond³

et al. 2018

Preprint

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The management of the electrical energy still raises a huge interest for end-users at the household level. Home electricity management systems (HEMS) have recently emerged both to warrant uninterruptible power and high power quality, and to decrease the cost of electricity consumption, by either shifting it in off peak time or smoothing it. Such a HEMS requires a bidirectional DC-AC converter, specifically when an energy transfer is required between a storage system and the AC-grid, and vice versa. This article points out the relevance of an innovative topology based on sinusoidal waveforms from the generation of sine half-waves. Such a topology is based on a DC-DC stage equivalent to an adjustable output voltage source and a DC-AC stage (H-bridge) which are in series. The results of a complete experimental procedure prove the feasibility to improve the power quality of the output signals in terms of total harmonic distortion (THD-values about 5%). The complexity of the proposed converter is minimized in comparison with multilevel topologies. Finally, wide band-gap semiconductor devices (SiC MOSFETs) are helpful both to warrant the compactness and the high efficiency (about 96%) of the bidirectional converter, whatever its operation mode (inverter or rectifier mode).

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Section: Limitations Of Existing Dc-ac Topologiesmentioning

confidence: 94%

Section: Limitations Of Existing Dc-ac Topologiesmentioning

confidence: 99%

An Innovative Bidirectional DC-AC Converter to Improve Power Quality in a Grid-Connected Microgrid

Bissey¹,

Jacques²,

Reymond³

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

“…In all three cases, only four active switches are used to realize the basic inverter circuit and reduce the leakage current until practically eliminate it. The reduction in common-mode frequency has also been achieved using transformerless topologies with multilevel neutral point clamp [68] or its variant, using split inductors [69].…”

Section: Common-grounded Invertermentioning

confidence: 99%

Leakage Current Reduction in Single-Phase Grid-Connected Inverters—A Review

et al. 2020

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The rise in renewable energy has increased the use of DC/AC converters, which transform the direct current to alternating current. These devices, generally called inverters, are mainly used as an interface between clean energy and the grid. It is estimated that 21% of the global electricity generation capacity from renewable sources is supplied by photovoltaic systems. In these systems, a transformer to ensure grid isolation is used. Nevertheless, the transformer makes the system expensive, heavy, bulky and reduces its efficiency. Therefore, transformerless schemes are used to eliminate the mentioned disadvantages. One of the main drawbacks of transformerless topologies is the presence of a leakage current between the physical earth of the grid and the parasitic capacitances of the photovoltaic module terminals. The leakage current depends on the value of the parasitic capacitances of the panel and the common-mode voltage. At the same time, the common-mode voltage depends on the modulation strategy used. Therefore, by the manipulation of the modulation technique, is accomplished a decrease in the leakage current. However, the connection standards for photovoltaic inverters establish a maximum total harmonic distortion of 5%. In this paper an analysis of the common-mode voltage and its influence on the value of the leakage current is described. The main topologies and strategies used to reduce the leakage current in transformerless schemes are summarized, highlighting advantages and disadvantages and establishing points of comparison with similar topologies. A comparative table with the most important aspects of each converter is shown based on number of components, modes of operation, type of modulation strategy used, and the leakage current value obtained. It is important to mention that analyzed topologies present a variation of the leakage current between 0 to 180 mA. Finally, the trends, problems, and researches on transformerless grid-connected PV systems are discussed.

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“…The self-balancing method is investigated in three-level NPC-MLI using carrier-based modulation [31][32][33][34][35][36][37][38]. The same self-balancing method nearest three vector selection is used in Hybrid Neutral Point Clamped transformerless inverter [39,40]. In [41], a modified SVM method is suggested with over modulation operation using small, medium, and zero vector switching vectors for mitigating the zero-sequence circulating current.…”

Section: Introductionmentioning

confidence: 99%

Neutral Point Clamped Transformer-Less Multilevel Converter for Grid-Connected Photovoltaic System

Madasamy¹,

Verma

Rameshbabu

et al. 2021

Electronics

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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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A 5-level high efficiency low cost Hybrid Neutral Point Clamped transformerless inverter for grid connected photovoltaic application

Cited by 3 publications

References 10 publications

An Innovative Bidirectional DC-AC Converter to Improve Power Quality in a Grid-Connected Microgrid

An Innovative Bidirectional DC-AC Converter to Improve Power Quality in a Grid-Connected Microgrid

Leakage Current Reduction in Single-Phase Grid-Connected Inverters—A Review

Neutral Point Clamped Transformer-Less Multilevel Converter for Grid-Connected Photovoltaic System

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