Eleven-level Inverter Research Articles

A grid-connected eleven-level power conversion interface

ABSTRACT This paper proposes a grid-connected eleven-level power conversion interface (GCELPCI) for renewable power systems. The proposed GCELPCI is composed of a four-port DC-DC power converter (FPDDPC) and an eleven-level inverter (ELI). The FPDDPC combines a boost power converter and a transformer with a turn ratio of 2:1 to generate multiple combinations of the output voltages for the DC bus voltage of the ELI. The ELI integrates an asymmetric voltage technique on a T-type inverter to further convert the DC output voltages of FPDDPC into eleven-level AC voltage. A sinusoidal current is generated by the proposed GCELPCI through the filter inductor and injected into the power grid. Only nine power electronic switches are used in the ELI to generate an eleven-level AC voltage, the number of power electronic switches is reduced to simplify the power circuit. In addition, the capacity of the filter inductor is reduced. A digital signal processor (DSP) and a complex programmable logic device (CPLD) chip are used as the digital controller to complete a hardware prototype to verify the performance of the proposed GCELI.

Improvement of Power Quality Using Reduced Switch Count Eleven-Level Inverter in Smart Grid

This article proposed a hybrid control topology to cascaded multilevel-inverter (CMLI) using 11-level for the grid-tied photovoltaic generation system. The proposed hybrid technique combines an archerfish hunting optimiser (AHO) and Spike Neural Network (SNN); hence, it is called the AHO-SNN technique. The proposed control technique is to maintain the regulation of power or maximal energy conversion of the solar subsystem and reduce total harmonic distortion (THD). Here, the AHO is utilised to construct the optimum control signal dataset. The best control signals are estimated using a data set performed by SNN. The resultant control signals will regulate insulated-gate-bi-polar-switches (IGBT) of Cascaded MLI. The proposed AHO-SNN control topology determines the converter switching states by constructing the operating modes of the generation system. The system parameter changes and outside disturbances are optimally minimised with this control strategy. The proposed AHO-SNN control is done in MATLAB platform, and it evaluated their performance by using existing methods, like War Strategy Optimization Algorithm (WSO) Fuzzy Wavelet Neural Network (FWNN), Side-Blotched Lizard Algorithm (SBLA), Adaptive Neuro-Fuzzy Inference System (ANFIS), and Memetic Fire-Fly Algorithm (MFA). The result shows that the proposed approach based on THD is less than existing approaches.

Grid‐connected operation and control of single‐phase asymmetrical multilevel inverter for distributed power generation

In recent times, multilevel inverters (MLIs) are gaining popularity for grid integration of distributed power generation sources. In this paper, a proportional-resonant (PR) controller based on current control logic is proposed for a single-phase eleven-level inverter topology, enabling the integration of distributed power generation sources into the grid. The presented topology utilizes eight two-quadrant switches and three dc sources to produce an eleven-level output voltage. The level-shifted pulse width modulation (LS-PWM) scheme is used for providing switching signals to the inverter under grid-connected operation. Simulation and real-time results are presented for the eleven-level inverter to validate the presented current control logic under the grid-connected mode of operation. The hardware-in-loop emulator (Typhoon HIL-402) is used for taking real-time results of the presented grid-connected topology. The total harmonic distortion (THD) of the eleven-level inverter voltage and grid current is 12.10% and 0.46%, respectively. The efficiency of the inverter while supplying 2 kW active power to the grid is 98.4%.

Active and reactive power control of grid‐connected single‐phase asymmetrical eleven‐level inverter

In recent times, multilevel inverters (MLIs) have become very popular for commercial and industrial applications. Here, an eleven-level inverter and its power flow control are presented. The presented topology has a lesser component count than other existing topologies, thus reducing the devices and overall cost of the inverter. This inverter comprises six bidirectional switches, two DC sources, one four-quadrant switch, and two capacitors for the voltage divider circuit. The conduction modes and corresponding switching states of the presented eleven-level inverter are shown in detail. Further, the apparent power control of the presented inverter under grid-connected operation is discussed, which provides simultaneous active and reactive power control over the power injected into the grid. Switching and conduction losses are calculated for 3 and 6 kVA grid injected power at 0.8 power factor lagging. The obtained results show that the total harmonic distortion (THD) of the inverter output voltage and grid current is 12.10% and 0.23%, respectively, under 6 kVA power transfer conditions. The real-time analysis is also carried out for 3 and 6 kVA power transfer conditions for the presented eleven-level inverter to validate the active and reactive power flow control.

Corrigendum to “A Novel Bio-Inspired Algorithm Applied to Selective Harmonic Elimination in a Three-Phase Eleven-Level Inverter”

Corrigendum to “A Novel Bio-Inspired Algorithm Applied to Selective Harmonic Elimination in a Three-Phase Eleven-Level Inverter”

A Novel Bio-Inspired Algorithm Applied to Selective Harmonic Elimination in a Three-Phase Eleven-Level Inverter

Selective harmonics elimination (SHE) is a widely applied control strategy in multilvel inverters for harmonics reduction. SHE is designed for the elimination of low-order harmonics while keeping the fundamental component equal to any previously specified amplitude. This paper proposes a novel bio-inspired metaheuristic optimization algorithm called Black Widow Optimization Algorithm (BWOA) for solving the SHE set of equations. BWOA mimics the spiders’ different movement strategies for courtship-mating, guaranteeing the exploration and exploitation of the search space. The optimization results show the reliability of BWOA compared to the state-of-the-art metaheuristic algorithms and show competitive results as a microalgorithm, opening its future application for an on-line optimization calculation in low requirement hardware.

Implementation of a new Bi-Directional Switch multilevel Inverter for the reduction of harmonics

In the current scenario, multilevel inverter plays a major role in heavy duty drive systems. MLI is one of the most advanced power converters for highly efficient AC output. But there is more to the requirement of number of control switches and total number of input sources which often generates more losses. This paper presents a new multilevel inverter design with limited number of control switches and with just one DC source to reduce these demerits. It uses a smaller number of Bi-directional switches. So that complexity of the circuit is reduced. Finally, an eleven-level inverter is designed and simulated using MATLAB/SIMULINK and THD reduction has been analyzed. This paper also provides a comparative statement of required components for various conventional methods.

Electric Boat Propulsion System Using Multilevel Converter Based on ANN Controller

In this system, we use a Multi-level inverter to power an electric boat propulsion system powered by PV Panels. The eleven-level inverter is used to supply power to multi-level switching cells of the inverter which drives the AC motor.It is an Asymmetrical Cascaded H-bridge Inverter. A Multi Carrier PWM signal is given based on Multi Carrier Modulation Technique to obtain equal steps in the eleven-level output. A Sepic converter is used which allows adjustment of a range of DC voltages to provide a constant voltage output. It is a DC converter that basically regulates the voltage from the PV Panel and all subtractive and additive combinations of DC input levels can be obtained in the output signal. ANN controller is applied forming an efficient closed loop system that is involved in the elimination of harmonics in PWM inverters.It reduces the overall Total Harmonic distortion. The system consists of optimized PI based MPPT that ensures efficient PV power generation.

An Artificial Neural Network Approach for Solving the Harmonic Distortions Elimination in Multilevel Converters

In this paper, a neural approach is applied to determine the switching angles for a uniform step asymmetrical multilevel inverter by eliminating specified higher-order harmonics while maintaining the required fundamental voltage. A Multi-Layer Perceptron (MLP) neural network is used to approximate the function between the modulation rate and the required switching angles. After learning, the artificial neural network is able to determine the appropriate switching angles for the inverter. This leads to a low-computational-cost neural controller which is therefore well suited for real-time applications. This technique can be applied to multilevel inverters with any number of levels. As an example, a nine-level inverter and an eleven-level inverter are considered and the optimum switching angles are calculated on-line. The neural approach is compared to the well-known sinusoidal Pulse-Width Modulation (PWM) strategy. Simulation results demonstrate the better performances and technical advantages of the neural controller in feeding an asynchronous machine. Indeed, the harmonic distortions are efficiently cancelled providing thus an optimized control signal for the asynchronous machine. Moreover, the technique presented here substantially reduces the torque undulations.

Simulation Analysis of PV Based Single Phase Modified H-Bridge Eleven Level Inverter

This study presents the simulation analysis of a PV based single-phase modified H-bridge eleven-level inverter. Multilevel inverters offer high power capability, associated with lower output harmonics and lower turn-off losses. This study informs a PV based multilevel inverter using a H-bridge output stage with four bidirectional auxiliary switches. The inverter is capable of producing eleven levels of output-voltage levels (+V dc/5, +2V dc/5, +3Vdc/5, +4V dc/5, +V dc, '0' level, -Vdc/5, -2Vdc/5, -3Vdc/5, -4Vdc/5 and -Vdc) from the DC supply. Theoretical predictions of the proposed PV based single-phase modified H-bridge eleven-level inverter with MPPT are validated using simulation in MATLAB SIMULINK.

Simulation Model of Single-Phase Simplified Eleven-Level Inverter

paper presents simulation model of a single phase simplified eleven-level inverter (SELI). Multilevel inverter offers high power capability. Its performance is highly superior to that of conventional two-level inverter due to reduced harmonic distortion, lower electromagnetic interference and higher dc link voltage. The inverter is capable of producing eleven levels of output voltages (Vdc, 4Vdc/5, 3vdc/5, 2Vdc/5, Vdc/5, 0, -Vdc/5, -2Vdc/5, -3Vdc/5, -4Vdc/5, -Vdc) from the DC supply voltage. Theoretical predictions are validated using MATLAB Simulink tool box. Keywordsclamped, diode clamped, multilevel inverter, H- bridge, Simplified Eleven-level Inverter (SELI).