A New Modular Multilevel Inverter Based on Step-Up Switched-Capacitor Modules

Abstract

A new structure of switched capacitor multilevel inverter (SCMLI) capable of voltage boosting and with self-balancing ability is introduced in this article. This advantage is the result of a step by step rise of capacitor voltages in each module, supplied by just one DC voltage source. The proposed topology generates a sinusoidal output waveform with a magnitude several times greater than the input one. Higher output staircase AC voltage is obtained by applying a nearest level control (NLC) modulation technique. The most significant features of this configuration can be mentioned as: fewer semiconductor devices, remarkably low total harmonic distortion (THD), desirable operating under high /low frequency, high efficiency, inherent bipolar voltage production, easy circuit expansion, ease of control and size reduction of the circuit thanks to utilizing neither bulky transformer nor inductor. Moreover, the proposed SCMLI is comprehensively surveyed through theoretical investigation and a comparison of its effectiveness to recent topologies. Eventually, the operating principle of a 25-level prototype of the suggested SCMLI is validated by simulation in the MATLAB SIMULINK environment and experimental results.

Circuit Configuration and Modulation of a Seven-Level Switched-Capacitor Inverter

“…One of the most essential traits for such converters (especially in many renewable energy applications with low voltage DC source such as solar systems) which standard MLI circuits do not possess is boosting capability. The voltage boosting is realized by charging capacitors and then summing the capacitors voltages up in a series connection to be applied to the output, eliminating the need for bulky transformers or inductors [20][21].…”

A Comprehensive Review on Grid Connected Photovoltaic Inverters, Their Modulation Techniques, and Control Strategies

“…To overcome these problems, multilevel inverter (MLI) topologies were introduced for GCPPPs as they have the ability to provide good quality output waveforms with low harmonic distortion, lower stress on switches, a lesser requirement of passive filter, and require less maintenance [6][7][8]. The MLIs are classified into various types based on the power circuitry structure such as reduced switch [9,10], asymmetric [11], modular [12], and hybrid [13,14], etc. The quality of output waveforms of MLIs greatly depends on the modulation technique (MT) applied to the switches (metal oxide silicon field effect transistor, insulated gate bipolar transistor, etc.).…”

A Multi-Cell 21-Level Hybrid Multilevel Inverter Synthesizes a Reduced Number of Components With Voltage Boosting Property

“…This can be achieved by applying a series connection between multiple units either with a combination of similar units as in modular multilevel converters cases. [3,6], or a cascaded connection between different MLIs topologies as in hybrid systems [7,8]. Some of the MLI's topologies present voltage boosting ability that aids in the voltage amplification in some industrial applications.…”