Seven-level Multilevel Inverter Research Articles

Total harmonic distortion optimization in a seven level multilevel inverter by the random search heuristic algorithm

In this article, the random search heuristic optimization algorithm is proposed to guarantee that the voltage synthesized by a seven-level multilevel inverter contains the lowest possible total harmonic distortion. The algorithm in this work is presented as an alternative, simple, and easy-to-implement method for solving a set of transcendental mathematical equations of multilevel inverters. The obtained results demonstrate the algorithm's capability to solve the mathematical formulation that minimizes the total harmonic distortion. It is important to highlight that the algorithm was implemented in Matlab®, and the obtained results were validated in a simulation conducted in Simulink®. Equally and not less important, the results were physically implemented in a laboratory prototype of three integrated circuits with H-bridges containing insulated gate bipolar transistors.

A new flying capacitor multilevel converter topology with reduction of power electronic components

High power capacity and reliability are characteristics of multilevel inverters. The using a collection of DC sources can produce a terminal voltage that is very close to sinusoidal. The power quality can be improved by adding more levels, but this makes the control system more complicated and expensive. The number of power components in a multilevel inverter has been studied for decades. So, research needs to be done on multilevel inverter configurations to find ways to add levels with fewer power switches than with traditional topologies and those that have already been proposed. In this research, a new power-efficient arrangement of a flying-capacitor inverter is introduced. In order to illustrate the suggested topology, a seven-level multilevel inverter is constructed and demonstrated in a simplified form. Fewer power components, including power switches, capacitors, and gate driver circuits, are required in this topology than in other topologies described in the recent literature, which is one of its main advantages. The improvement mentioned above can be seen in the way this topology works, which is shown by the characteristics of the circuit. MATLAB/Simulink R2021a is used to simulate and verify the circuit to ensure the proposed topology is correct.

Quasi-Resonant Switched-Capacitor-Based Seven-Level Inverter With Reduced Capacitor Spike Current

This article proposes a novel seven-level multilevel inverter (MLI) with integrated output voltage boosting functions. The inverter uses switched capacitors (SCs), a key component of a voltage-boosting approach, to achieve the goal of increasing the output voltage at the load end. Additionally, the MLI has the ability to automatically balance the capacitor voltages. The proposed inverter is more cost-effective and has lower conduction losses than those of its rivals since it has fewer components than competing designs. An inductor is used in the capacitor charging loop to both minimize dc source current spikes and enable quicker charging of the capacitor, thereby increasing the capacitor’s lifespan. This article provides a number of waveforms, including output voltage and current, under various loading conditions and modulation indices. A laboratory model is also employed to support the viability of the proposed topology. The performance of the system is verified using MATLAB/Simulink. At long last, the maximum achievable experimental efficiency of 98.77% and total harmonic distortion (THD) for output voltage and current were 20.44% and 0.54%, respectively, at 300 V and 1.2 kW load.

Differential Evolution Applied to a Multilevel Inverter—A Case Study

This work aims to obtain the switching angles to reduce the total harmonic distortion (THD) and compare the different sets of angles obtained by modifying the modular index (Mi) in a seven-level multilevel inverter using the differential evolution (DE) algorithm. A seven-level cascaded multilevel inverter with RL load was simulated in MATLAB Simulink. The Mi was varied (0.6 to 1.27) to check which set of switching angles is optimal to reduce the THD. These sets of angles are then experimentally validated on a test bench. A brief discussion of the results is presented, comparing the minimum THD found without considering Mi, versus the minimum THD obtained if Mi is less than 1.

A Performance evaluation of a fuzzy logic controller-based Photovoltaic-fed multi-level inverter for a three-phase induction motor

Today, the quality of accessible power and the response of the system involved are most significant. Many controllers have been used by researchers dealing with issues pertaining to power. Controllers play a significant role in the renewable energy sector in terms of improving the quality of power and offering a speedy system response. This research analyzes the speed of response and harmonics and enhances system performance overall. The existing system consists of a photovoltaic panel, boost converter, multi-level inverter, classic proportional-integral (PI) controller, and three-phase induction motor. The proposed system comprises a photovoltaic-based multi-level inverter, fuzzy logic controller, buck-boost converter, and three-phase induction motor. The output of the photovoltaic panel is connected to a buck-boost converter, and that of the converter to an inverter, while the output of the seven-level multi-level inverter is connected to a three-phase induction motor. Motor speed is controlled by a fuzzy logic controller (FLC). The output of the proportional-integral (PI) controller is compared to that of the fuzzy logic controller. The behavior and performance of the existing system are verified with experimental setup and proposed system are verified by MATLAB and Simulink, and the results recorded.

Investigation of fault-tolerant capabilities of some recent multilevel inverter topologies

ABSTRACT In this paper, some recently proposed multilevel power converters are investigated for their fault-tolerant capabilities and improved reliability. These reported topologies are generally reduced device multilevel inverter (RD-MLIs) configurations that cannot tolerate switch failures due to absence of redundant states. Present work therefore aims to incorporate open-circuit fault-tolerant capability by adding few redundant states in switching sequences of existing topologies. The work in this paper objectively presents two existing topologies of five-level and seven-level Multi-Level Inverters (MLIs) modified for fault-tolerant (FT) capability against single switch open-circuit (OC) faults. The modification for fault-tolerant feature (FT-MLI) has intrinsic self-voltage balancing capability, low cost and control simplicity. The modified FT-MLI uses multi-carrier sinusoidal pulse-width modulation (SPWM) technique to generate control switching pulses as per desired switching sequences. Simulation and experimental results of these modified FT-MLI topologies under healthy, faulty and post-fault mode are presented and discussed. Experimental results verify the feasibility and effectiveness of these modified FT-MLI topologies which are suitable for safety-critical applications.

A Performance Improvement of the Fuzzy Controller-Based Multi-Level Inverter-Fed Three-Phase Induction Motor with Enhanced Time and Speed of Response

Right now, research in the power sector has generally limited itself to issues, for example, the nature of power and its improvement, with much research, focused on the two. Power network operations are constrained by non-direct electronic electronics that disrupt power systems. Power system issues harmonics, ripples, electromagnetic induction (EMI), voltage sags, voltage swells, and regulation, harmonics, the speed of response of the system, and the time response of the system. The tasks of the existing system depend on the working of the fractional-order proportional-integral (FOPID) controller, which comprises a photovoltaic panel, buck–boost converter, seven-level multi-level inverter, three-phase induction motor, and FOPID controller. The proposed framework comprises a fuzzy logic controller (FLC); PV-fed seven-level multi-level inverter and buck–boost converter, with a three-phase induction motor giving the heap. The simulation model worked for both the current and proposed frameworks is by MATLAB Simulink, and the outcomes for both are analyzed and recorded. The examination shows that the proposed framework has a quicker speed of reaction, time reaction, and lower THD esteem than the current framework.

Enhancing the Performance of Multilevel Inverters using Modified SVPWM Techniques

In this paper, two types seven-level multilevel inverters in three phase configuration, Cascaded H-bridge Multilevel Inverter (CMLI) and Diode Clamped Multilevel Inverter (DCMLI) are simulated and compared the results for three different carrier PWM techniques. Here, Carrier based Sinusoidal Pulse Width Modulation (SPWM), Third Harmonic Injected Pulse Width Modulation (THIPWM) and Modified Carrier-Based Space Vector Pulse Width Modulation (SVPWM) are used as modulation strategies. These modulation strategies include Phase Disposition technique (PD), Phase Opposition Disposition technique (POD), and Alternate Phase Opposition Disposition technique (APOD). In all the modulation strategies, triangular carrier and trapezoidal triangular carrier signals are compared with reference signal for generation of control pulses. The simulations have been carried out for seven-level CMLI and DCMLI using MATLAB/Simulink. The detailed analysis of results in terms of %THD and utilization of DC-link voltage has been presented in this paper. By increasing the performance of inverters the utilization of input energy is reduced, then the corresponding energy sources can be reduced.

Seven Level Inverter Fault Mitigation Using Redundant Cell for Induction Motor Drive

<span lang="EN-US">Fault identification is as much important as prior knowledge to mitigate the faults that might occur in inverter driven induction motor drives. In this paper, seven-level multi level inverter was taken up for testing of mitigation using redundant cell and the results were compared with five-level inverter to exhibit the performance of mitigation policy. This paper presents analysis of inverter feeding an induction motor drive when switch open and short fault occurs. When the fault occurs, the redundant cell activates and thus the drive system operates. In this paper, the function for redundant cell was explained with the results of drive system simulated in Matlab/Simulink.</span>