Evaluation and analysis of transformerless photovoltaic inverter topology for efficiency improvement and reduction of leakage current

Cha, Woo-Jun; Kim, Kyu-Tae; Cho, Yong Won; Lee, Sungho; Kwon, Bong-Hwan

doi:10.1049/iet-pel.2014.0401

Cited by 96 publications

(42 citation statements)

References 24 publications

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“…On the other hand, in comparison with other SCMLIs that have the potential to boost the voltage, only the proposed topology can eliminate the leakage current, and other SCMLIs suffer from this issue. In addition, the topologies introduced in Table 3 which can eliminate the leakage current [23]- [26] are not capable to increase the voltage and required boost circuitry. The proposed inverter, unlike traditional SCMLIs, does not need to H-bridge circuit.…”

Section: Comparison Discussionmentioning

confidence: 99%

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A New Topology of Switched-Capacitor Multilevel Inverter With Eliminating Leakage Current

et al. 2020

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This paper proposes a new topology of the switched-capacitor multilevel inverter (SCMLI) for photovoltaics system, which can eliminate the leakage current. In the proposed topology, the capacitors are employed as a virtual DC power supply to boost the input voltage. Here, all capacitors are charging equal to DC source, thus, just one DC source is needed to achieve the staircase waveform. In this structure in order to make the negative levels, the capacitors are connected to the output in reverse polarity. Thus, the H-bridge circuit which is used in traditional SCMLI to build zero and negative voltage levels and leads a variable common mode voltage is removed. Due to the direct connection of the neutral terminal of the grid to the negative polarity of the PV; then this topology can eliminate the leakage current. In addition, the topology has an excellent ability to path the reverse current as well as an acceptable output waveform spectrum. The operating states of all components and loss calculations are analyzed and formulated accurately as well as simulated by using MATLAB-SIMULINK software. To confirm the performance of the proposed topology; a 500 W prototype is built and experimental results are presented. INDEX TERMS Switched capacitor, multilevel inverter, leakage current, H-bridge, common mode voltage.

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Section: Comparison Discussionmentioning

confidence: 99%

“…On the other hand, all conventional switchedcapacitor inverters suffer from the H-Bridge circuit to build negative polarity voltage levels at the output, which leads to a variable common mode voltage and thereby generating leakage current. Thus, it requires extra circuitry elements to obtain the constant CMV [22], [23].…”

Section: Introductionmentioning

confidence: 99%

A New Topology of Switched-Capacitor Multilevel Inverter With Eliminating Leakage Current

et al. 2020

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“…The differences between the conventional and proposed topologies with the different PWM modulation modes shown in Fig.3 lead to different efficiency situations. There are already a number of studies on the losses analysis of boost converters, buck converters or single stage grid-connected inverters [18]- [19]. However, there have been few studies on the integrated calculation and analysis of the overall efficiency of two-stage inverters.…”

Section: Losses and Efficiency Comparative Analysis Of The Convementioning

confidence: 99%

A High Efficiency Two-stage Inverter for Photovoltaic Grid-connected Generation Systems

Liu¹,

Song²,

Shen³

2017

Journal of Power Electronics

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Conventional boost-full-bridge and boost-hybrid-bridge two-stage inverters are widely applied in order to adapt to the wide dc input voltage range of photovoltaic arrays. However, the efficiency of the conventional topology is not fully optimized because additional switching losses are generated in the voltage conversion so that the input voltage rises and then falls. Moreover, the electrolytic capacitors in a dc-link lead to a larger volume combined with increases in both weight and cost. This paper proposes a higher efficiency inverter with time-sharing synchronous modulation. The energy transmission paths, wheeling branches and switching losses for the high-frequency switches are optimized so that the overall efficiency is greatly improved. In this paper, a contrastive analysis of the component losses for the conventional and proposed inverter topologies is carried out in MATLAB. Finally, the high-efficiency under different switching frequencies and different input voltages is verified by a 3 kW prototype.

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“…One of the drawbacks of PV transformerless inverters is the generating of leakage current due to the absence of a transformer. High generation of leakage current increases system losses, total harmonic distortion (THD), electromagnetic interference (EMI) and can cause personal safety issues [8][9][10][11]. The literature cites various modulation techniques that have been used to eliminate or minimize leakage current.…”

Section: Introductionmentioning

confidence: 99%

An Improved Proposed Single Phase Transformerless Inverter with Leakage Current Elimination and Reactive Power Capability for PV Systems Application

Almasoudi

Matin

2018

JLPEA

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Single-phase transformerless inverters are broadly studied in literature for residential-scale PV applications due to their great advantages in reducing system weight, cost and elevating system efficiency. The design of transformerless inverters is based on the galvanic isolation method to eliminate the generation of leakage current. Unfortunately, the use of the galvanic isolation method alone cannot achieve constant common mode voltage (CMV). Therefore, a complete elimination of leakage current cannot be achieved. In addition, modulation techniques of single-phase transformerless inverters are designed for the application of the unity power factor. Indeed, next-generation PV systems are required to support reactive power to enable connectivity to the utility grid. In this paper, a proposed single-phase transformerless inverter is modified with the clamping method to achieve constant CMV during all inverter operating modes. Furthermore, the modulation technique is modified by creating a new current path in the negative power region. As a result, a bidirectional current path is created in the negative power region to achieve reactive power generation. The simulation results show that the CMV is completely clamped at half the DC link voltage and the leakage current is almost completely eliminated. Furthermore, a reactive power generation is achieved with the modified modulation techniques. Additionally, the total harmonic distortion (THD) of the grid current with the conventional and a modified modulation technique is analyzed. The efficiency of the system is enhanced by using wide-bandgap (WBG) switching devices such as SiC MOSFET. It is observed that the efficiency of the system decreased with reactive power generation due to the bidirectional current path, which leads to increasing conduction losses.

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Evaluation and analysis of transformerless photovoltaic inverter topology for efficiency improvement and reduction of leakage current

Cited by 96 publications

References 24 publications

A New Topology of Switched-Capacitor Multilevel Inverter With Eliminating Leakage Current

A New Topology of Switched-Capacitor Multilevel Inverter With Eliminating Leakage Current

A High Efficiency Two-stage Inverter for Photovoltaic Grid-connected Generation Systems

An Improved Proposed Single Phase Transformerless Inverter with Leakage Current Elimination and Reactive Power Capability for PV Systems Application

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