In this paper, a dc to ac converter with the ability of voltage increasing is presented. This inverter is designed in a way that just one dc source is used. Also, by using power storage technique and with combining charged capacitors and dc source in series form, output voltage levels can be increased. This inverter is in a modular structure and has the ability of capacitor's voltage self-balancing. H-bridge inverter was not used at the end of the proposed converter and all elements tolerate a voltage stress equal to the amount of input dc source. This leads to remarkable decrease of total standing voltage and peak inverse voltage. Other advantage of the proposed inverter is its potentiality of performance in high-frequency applications. The modular form of the proposed inverter provides the potentiality of extension to higher voltage levels and eases the maintenance. Moreover, considering to the fact that the stress of all components of the suggested inverter is equal to the input source, the performance in high voltage is added to the characteristics of the proposed inverter. The nine-level structure of the proposed inverter is simulated and laboratory test is carried out for the verification of its performance.

This study presents a new topology of switched‐capacitor (SC) multilevel inverter, which is able to step‐up input DC voltage to a multilevel AC waveform. This single source inverter is designed based on series connection of the capacitors that charged by input DC sources through a SC network. The proposed modular inverter uses famous T and cross‐connected modules that can be simply extended to higher output voltages without increasing the amount of total standing voltage and peak inverse voltage of switches. It generates positive and negative voltage levels inherently, which eliminates requirements of H‐bridge inverters that are traditionally used to achieve a bipolar output voltage. Analysis shows that the voltage stress on components, cost, efficiency and losses are kept in acceptable range especially for higher‐voltage levels. Capacitor's voltage self‐balancing is another inherent advantage of this modular topology which leads to simplify control strategy and eliminate excess balancing circuit. Performance of a six‐step proposed structure is evaluated by theoretical analysis, simulation and experimental results.

Modern industrial and commercial devices that are fed by power electronics circuits and behave non-linearly tend to produce power quality issues in power systems including harmonics and interharmonics, swell, flicker, spikes, notches, and transient instabilities. Among them, harmonic emission is the most significant challenge to be overcome by the distribution networks. Unwanted current, overheating motors and transformers, equipment failure, and circuit breaker misoperation are some of the harmonic consequences. While it is important to employ the best methods to mitigate or suppress the harmonic distortions in power systems, it is even more essential to estimate these harmonics at the outset by developing smart, efficient, and accurate techniques. Due to their capability for learning, predicting, and identifying, researchers have turned to Artificial Intelligence technologies for harmonic estimation in distribution networks. Although the power system parameters (impedance/admittance model) and many harmonic monitors are prerequisites for traditional harmonic estimation methods, by utilizing Artificial Intelligence, these requirements are minimized. In this paper, a comprehensive review of traditional and modern (smart) harmonic estimation techniques are discussed.

This paper presents a switched-capacitor multilevel inverter (SCMLI) combined with multiple asymmetric dc sources. The main advantage of proposed inverter with similar cascaded MLIs is reducing the number of isolated dc sources and replacing them with capacitors. A self-balanced asymmetrical charging pattern is introduced in order to boost the voltage and create more voltage levels. Number of circuit components such as active switches, diodes, capacitors, drivers, and dc sources reduces in proposed structure. This multistage hybrid MLI increases the total voltage of used dc sources by multiple charging of the capacitors stage by stage. A bipolar output voltage can be inherently achieved in this structure without using single phase H-bridge inverter that was used in traditional SCMLIs to generate negative voltage levels. This eliminates requirements of high-voltage rating elements to achieve negative voltage levels. A 55-level step-up output voltage (27 positive levels, a zero level, and 27 negative levels) are achieved by a three-stage system that uses only three asymmetrical dc sources (with amplitude of 1 V_in, 2 V _in, and 3 V_in) and seven capacitors (self-balanced as multiples of 1 V_in). MATLAB/SIMULINK simulation results and experimental tests are given to validate the performance of proposed circuit.

This study is an attempt to present a multilevel inverter based on a modular structure with a single dc source. This inverter is a switched-capacitor topology, which controls the charging as well as the discharging of the capacitors in the predetermined time intervals. The most important attribute of this multistage structure is the multiple charging capacities of the capacitors at each stage compared with those of the previous stages, which can ultimately increase the output voltage of the low input dc voltage source. Different combinations of these capacitors will be discharged across the load to generate a high-level staircase ac voltage waveform. The high number of switching states provides different paths for capacitors to achieve a self-balancing capability. The low switching frequency and the elimination of transformer are among the advantages of the proposed topology. Compared with other topologies, the number of semiconductor devices and capacitors is also reduced largely. The simulation results and the laboratory test setup of a 49-level inverter using DSP TMS320F28335 are presented to verify the analysis.

This paper proposed a grid connected solar Photovoltaic (PV) Systems with a new voltage balancing converter suitable for Neutral-Point-Clamped (NPC) Multilevel Inverter (MLI). The switched-capacitors used in the proposed converter is able to balance the DC link capacitor voltage effectively by using proper switching states. The proposed balancing converter can be extended to any higher levels and it can boost the DC input voltage to a higher voltage levels without using any magnetic components. This feature allows the converter to operate with the boosting capability of the input voltage to the desired output voltage while ensuring the self-balancing. In this paper the proposed converter is used for a grid connected solar PV system with NPC multilevel inverter, which is controlled using vector control scheme. The proposed grid connected solar PV system with associated controllers and maximum power point tracking (MPPT) is implemented in Matlab/SimPowerSystem and experimentally validated using dSPACE system and designed converters. The simulation and experimental results show that the proposed topology can effectively balance the DC link voltage, extract maximum power from PV module and inject power to the grid under varying solar irradiances with very good steady state and dynamic performances.