A Generalized Multilevel Inverter Based on T-Type Switched Capacitor Module with Reduced Devices

Abstract

Conventional multilevel inverters have problems in terms of their complicated expansion and large number of devices. This paper proposes a modular expanded multilevel inverter, which can effectively simplify the expansion and reduce the number of devices. The proposed inverter can ensure the voltage balancing of the voltage-dividing capacitors. The cascading of the T-type switched capacitor module and the step-by-step charging method of the switched capacitors enable the inverter to achieve high output voltage levels and voltage gain. In addition, the inversion can be achieved without the H-bridge, which greatly reduces the total standing voltage of the switches. The nine-level inverter of the proposed topology can be realized with only ten switches, obtaining a voltage gain that is two times larger. The above merits were validated through theoretical analysis and experiments. The proposed inverter has good application prospects in medium- and low-voltage photovoltaic power generation.

New Nine-Level Cascade Multilevel Inverter with a Minimum Number of Switches for PV Systems

“…Figure 14 depicts a nine-level switching capacitor MLI in single-phase mode proposed in [63]. The suggested topology involved boosted voltage and self-balanced capacitor voltage to control the switch states and generate various voltage levels [64]. Three capacitors (C1, C2, and C3), ten switches (S1 to S10), and a single input voltage source make up each phase.…”

“…The proposed circuit genera voltage levels (0, 0.5 Vdc, Vdc, 1.5 Vdc, and 2 Vdc). Figure 15 depicts a nine-level multilevel inverter based on a T-type switched capacitor module with a reduced number of switches (S1-S10) and a single DC source with four capacitors and two diodes [64]. Jafar Siahbalaee [65] compared a conventional multilevel inverter with a novel cascaded multilevel inverter to showcase several new cascaded topologies (NCTs) with nine levels, four DC sources, and multiple switches in each cascaded topology, as well as other indices.…”

“…PWM control algorithms used with MLIs significantly impact their efficiency, power ratings, and applications [15]. Over the past few decades, several studies have proposed various MLI topologies with a reduced number of switches [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65].…”

“…Figure15depicts a nine-level multilevel inverter based on a T-type itor module with a reduced number of switches (S1-S10) and a single four capacitors and two diodes[64].…”