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

Abstract

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.

A Cross Connected Asymmetrical Switched-Capacitor Multilevel Inverter

“…All three proposed topologies have the advantage of voltage gain and capacitor voltage balancing ability. A new SC-topology having cross-connected switches is proposed in [23]. The topology configuration is such that the leakage current is eliminated, but it uses a higher number of components for higher levels.…”

A Dual Source Switched-Capacitor Multilevel Inverter with Reduced Device Count

“…Initially, the inclusion of capacitors in MLIs can be observed in the two classical configurations, NPC and FC themselves. Recently, SCMLI-based topologies, including combinations of capacitors and switch modules in series/parallel configuration, have gained researchers' attention, particularly for applications where a voltage boosting feature is advantageous [13][14][15][16][17]. Low magnitude voltage, including PV or fuel cell, can be significantly increased as a result of this boosting feature.…”

Single-Stage Three-Phase Grid-Tied Isolated SEPIC-Based Differential Inverter With Improved Control and Selective Harmonic Compensation

“…This topology processes the power twice (two-stage inverters), which are extensively studied and adds many limitations for the component count and the control complexity. During the last decade, many topologies have been introduced using the same approach, such as switched-capacitor based inverters [18][19][20][21][22][23][24], Z source inverters [25][26][27][28][29], and multi-level inverters [30][31][32].…”

“…This circuit can charge and discharge in parallel and series to boost the input DC voltage. However, this topology has many component counts, especially at the three-phase systems [18][19][20][21], and lacks galvanic isolation and modular construction [23]. Also, it has many issues related to the capacitors' mismatch and their selfvoltage balancing [24].…”