A New Six-Level Transformer-Less Grid-Connected Solar Photovoltaic Inverter With Less Leakage Current

Abstract

This paper presents a novel structure of the transformer-less grid-connected inverters. The proposed inverter is combined with six power switches and two power diodes which can generate six voltage levels at the output. Furthermore, the proposed inverter can overcome the leakage current issue in the photovoltaic (PV) system, which is the major problem in grid-tied PV applications. Additional significant features include-reduced filter size, lower total harmonic distortion (THD) of the injected current to the grid, and voltage boosting ability. Moreover, the proposed topology provides full reactive power support to the grid. A control strategy is designed and implemented to provide a voltage boost ability without using any additional dc-dc boost converter. Finally, the performance of the proposed inverter is validated by the 770 W laboratory prototype.INDEX TERMS Transformer-less inverter, voltage boosting ability, leakage current limitation, and photovoltaic application.

A new transformer‐less common grounded five‐level grid‐tied inverter with leakage current elimination and voltage boosting capability for photovoltaic applications

“…So, the common mode leakage current can be limited the PV‐based grid‐tied systems. A similar concept is discussed in [19]. In the mentioned reference, a new six‐level NPC‐based grid‐tied topology involving the switched capacitor method is proposed.…”

“…Herein, a unipolar PWM method can be adapted and the quality of the injected current can be enhanced significantly. In some recently presented transformer-less NPC-based inverters, switched capacitor units are applied to improve the voltage gain and generate boosted output levels [18][19][20]. In [18], a new transformer-less NPC-based seven-level inverter is presented, which uses a switched capacitor unit.…”

A New Single DC Source Five-Level Boost Inverter Applicable to Grid-Tied Systems

“…Therefore, a huge number of multilevel inverters with reduced circuit components have been presented in the literature. In these structures, the main purpose is reducing the number of the required power switches [1]- [4] and DC voltage sources [5]- [10]. In order to provide higher number of output voltage levels (high resolution), the presented inverters with reduced number of components contain considerably lower number of components in comparison with conventional inverters.…”

An improved nine‐level switched capacitor‐based inverter with voltage boosting capability and limitation of capacitor current spikes for PV applications

“…Among these solutions, integration of renewable energy sources (RESs) into power systems is one of the most popular and widely accepted solutions. At the large family of RESs, photovoltaic (PV) systems are of the widely used members [4][5][6]. However, to employ and integrate these sources into the power systems, power electronic based interfaces, that is, power converters, are inevitable [7][8][9][10].…”