Review of Multilevel Inverters for PV Energy System Applications

Abstract

Over the last decade, energy demand from the power grid has increased significantly due to the increasing number of users and the emergence of high‐power industries. This has led to a significant increase in global emissions with conventional energy generation. Therefore, the penetration of renewable energy resources into the power grid has increased significantly. Photovoltaic systems have become the most popular resources as their protentional is enormous, thus, the worldwide installed PV capacity has increased to more than 635 gigawatts (GW), covering approximately 2% of the global electricity demand. Power electronics are an essential part of photovoltaic generation; the drive for efficient power electronic converters is gaining more andmore momentum. Presently, multilevel inverters (MLI) have become more attractive to researchers compared to two‐level inverters due to their abilities to provide lower electromagnetic interference, higher efficiency, and larger DC link voltages. This paper reviews multilevel inverters based on their classifications, development, and challenges with practical recommendations in utilizing them in renewable energy systems. Moreover, PV systems with various maximum power point tracking (MPPT) methods have been extensively considered in this paper as well. The importance and thedevelopment of a modified multilevel inverter are also highlighted in this review. In general, this paper focuses on utilizing multilevel inverters for PV systems to motivate and guide society to focus on inventing an efficient and economical multilevel inverter that has the combined capabilities of these converters reported in the literature.

Modular Multilevel Converters for Large-Scale Grid-Connected Photovoltaic Systems: A Review

“…The hybrid MPPT controllers combine two MPPT approaches in the same application, and they have the potential to increase overall efficiency while also performing well in partial shade conditions [121]. Furthermore, hybrid controllers can outperform individual algorithms when it comes to obtaining better tracking responses [24]. In [122], a hybrid MPPT controller was presented that combines the PandO and PSO methods in partial shading conditions.…”

“…In this context, modular multilevel inverters (MMIs) emerge as a potential solution to solve the problems and improve the performance of large-scale PV systems. There is an increasing interest in AC module systems with a series-connected multilevel structure, in recent years, to maximize harvested power and improve the efficiency of these large-scale PV systems when integrated into the MV grid [24]. MMIs provide the required modularity and scalability, which means that a large-scale PV system can generate high power with smaller semiconductor devices, as their inverter modules will be scaled up [25].…”

Multilevel Inverter: A Survey on Classical and Advanced Topologies, Control Schemes, Applications to Power System and Future Prospects

“…Figure 27 depicts the controller for adjusting the amplitude and the phase shift of the current injected from the inverter to the grid. In [235][236][237], researchers have addressed the use of a solar-based MLI for enhancement in the waveform quality and reduction in issues on power quality. For a three-level NPC-MLI, instantaneous power theory control is studied for generating the perfect reference signal.…”

A Single Source Switched-Capacitor 13-Level Inverter with Triple Voltage Boosting and Reduced Component Count

“…To overcome these issues, researchers have proposed a self-balanced switched-capacitor multilevel inverter (SCMLI), which can synthesize the desired voltage levels at the output using fewer components and reduced control complexity [6][7][8][9][10][11][12]. Several SCMLIs has been presented by researchers utilizing fewer components to realize the desired multilevel output voltage.…”

“…To reduce the number of switches, the authors in [19] used 19 switches for generating voltage boosting of six, but the TSV of the inverter circuit increased to 39. A detailed review on the recently published multilevel inverter topologies to find the most suitable applications with reduced device count is published in [7][8][9][10][11][12]. In the case of lower solar PV voltages, a high gain DC-DC converter along with multilevel inverter can be used to boost the PV voltage for obtaining desired output voltage for grid integration [24][25][26].…”