Single Phase Multilevel Inverter Research Articles

A Comparative Study of 9-Level Inverter and 15-Level Multi Inverter for a Grid Connected System

Abstract: Recently, the emergence of single phase multilevel inverter has been increased due to its advantages over traditional one. Multilevel Inverters [MLI] are the ones which can give out a stepwise output waveform with the use of power electronic switches, power diodes and some DC voltage source which might be a series/parallel connected PV cells, a renewable source or a battery. Multilevel inverters not only produce low harmonic distortion but also decrease the dv/dt stresses on the equipment Multilevel inverters is a good option as the output voltage of a Multilevel inverter is a stepped waveform which approaches a sinusoid providing lesser harmonic distortion. As the number of levels are increased the harmonic distortion reduces but at the same time the number of switching devices and the DC voltage sources required increases, thus increasing the complexity of the system design and control. Multilevel inverter proposed in this paper uses only 7 switches to provide 9 levels and 15 levels of output voltage. A symmetrical Cascaded H bridge Multi level inverter (SCHBMLI) and Asymmetrical Cascaded H bridge Multilevel Inverter (ASCHBMLI) using PD-PWM technique have been analysed in this paper for grid connection. The Asymmetric Cascade H Bridge [ASCHMLI] implemented in real time system using PIC16F877A microcontroller with RL load. This type of proposed system is used for high power applications in photovoltaic and it’s reduce overall cost as well as size of the system.

Implementation of novel toroidal transformer-based single-phase multilevel inverter

Implementation of novel toroidal transformer-based single-phase multilevel inverter

Effect of supply voltage variations on single-phase capacitor clamped multilevel inverter fed induction motor drive

This article presents the effect of supply voltage variations on single-phase capacitor-clamped multilevel inverter-fed induction motor drives. This research is tailored at determining the best torque value and speed to attain a stable state under input voltage variation and minimum time response to realize low percentage harmonic distortions. The effect of constant power quality disturbance harms the performance and behavior of asynchronous motors based on harmonic contents and other energy source integrations. The multilevel inverter has shown good performance in motor drives. This paper deals with the effect of input voltage variations on a single-phase multilevel capacitor-clamped inverter for asynchronous induction motor drives. A five-level capacitor-clamped inverter with an in-phase disposition pulse width modulation technique is adopted. Four high-frequency triangular carrier signals are generated and compared with a reference sinusoidal signal. As a result of this approach, the inverter switches firing signals are generated. The open-loop model is designed and simulated utilizing MATLAB/Simulink and results based on different values of supply voltage are presented. The current and voltage total harmonic distortions (THDs) obtained are 4.97% and 4.46% respectively at the best operating voltage of 400 V and at maximum torque of 47 Nm.

Performance evaluation of hybrid multilevel inverter with a high-frequency switching technique

This proposed work deals with the implementation of a single-phase topology with using hybrid for multilevel inverters. It is observed that the proposed structure improves the performance of the hybrid multilevel inverter with high-frequency switches for positive levels and reverse voltage with negative levels. This paper studies a novel construction for an asymmetrical hybrid single-phase multilevel inverter. This paper also studies the operation of multi level inverter under depreciating sources condition due to fluctuation in input. The PWM method, i.e. APOD and CO, has been incorporated into the simulation of single-phase 7-level, 9-level, and the 11-level hybrid inverter. These two methods are compared to one another and to standard methods in terms of THD for different values of the modulation index, and they are found to be superior. Overall loss of 50% of the THD is almost equal to rated output voltage, it is observed in cascaded multilevel inverters. The working and performance of the proposed model are simulated in MATLAB Simulink software and the results are discussed in detail.

Design of Hybrid multi-level inverter for photovoltaic(PV) application

Nowadays the demand and consumption of energy increase in the word. Due to high cost of fossil fuel it’s not able to meet the required power generation demand. But the developed and developing countries encourage to generate power from renewable energy sources. The developed countries manage their resources in such a manner that they will fulfill their needs today and in the future as well. Nevertheless, the developing countries have limited sources of fossil fuels, which may decrease day by day. For this problem, the alternate solution is required, which is renewable energy. The output of renewable i.e. photovoltaic (PV) is DC. Now this is a challenging task for the researcher to integrate the renewable energy into the ac grid. For the reliable future of the power system, it is imperative for the modern era to integrate non-conventional sources into the AC power grid.The use of photovoltaic cells is increasing dramatically in all areas of life because of their small environmental impact, pollution-free, minimal maintenance, and zero noise. The real work focuses on the integration of PV systems with the proposed new topology called Multi-level inverters based on switch dc sources for low, medium and high power applications. An inverter is a power electronics device that converts DC input to AC output voltage. Input DC voltage is obtains from PV cell array, fuel cell or any other source.The output of PV panels is use as DC input voltage source for the proposed inverter. Single-phase multi level inverter is use to convert dc power receiving form PV array to AC power. First single phase two level inverter introduce which have many problems like those that high value capacitor required at output and high total harmonics distortion’s (THD). Nevertheless, as the number of level increased in inverter output the number of electronic switches also increased which may increase the losses.Multi-level inverters are gave more attention for high power applications. In recent years, lower order harmonic components has been developed to operate at higher switching frequencies.On the other side as the number of level increased the output waveform approach to sinusoidal waveform and the harmonics decreased. Output voltage and current waveforms are obtains and THDs are analyze. The multi-level inverter used in un-interrupted power supply (UPS), variable frequency drives (VFD), pumps etc. The performance of single-phase multi-level inverter will be analyzed in MATLAB / Simulink software.

Analytical Approach to THD Formulation and Optimization in Sine-PWM-Based Single-Phase Multilevel Inverters With Variable DC Ratios

Asymmetric Multilevel Inverters (MLI) with Unequal Voltage Steps (UVS) are often combined with the Staircase Modulation (SCM) technique to improve both voltage and current THD - an approach known as Optimal Minimization of THD (OMTHD). This is usually achieved by varying both the Switching Angles (SA) and the DC source Ratios (DCR), to obtain the desired Modulation Index (MI) while THD is minimized. In this article, a novel Sine-PWM (SPWM) based OMTHD is considered as an alternative to SCM-based OMTHD. Because only the DCRs need to be optimized instead of both SAs and DCRs, the OMTHD process is simplified, while voltage THD, current THD, as well as power efficiency, are improved, especially for the medium-low MI range, compared to conventional SPWM. An analytical formulation of phase-voltage THD for UVS-based SPWM MLIs is derived and utilized for the novel SPWM-based OMTHD. Validation is carried out by theoretical analysis, digital simulations, and real-time C-HIL-based experiments.

Modified PDPWM control with MPPT algorithm for equal power sharing in cascaded multilevel inverter for standalone PV system under partial shading

<span lang="EN-US">In this paper, a modified particle swarm optimization (MPSO) based maximum power point tracking (MPPT) controller is used to track the maximum power of a PV system using DC-DC boost converter technology. </span><span lang="EN-GB">To raise the PV module's input DC voltage, a DC-DC boost converter was employed. The boost converter powered the DC-AC multilevel PWM inverter, which then delivered the output AC voltage to a solitary inductive load. Cascaded multilevel inverters are often used to condition power in renewable energy applications because they are easy to use and have few parts. Ripples in the voltage of DC link capacitors cause low order harmonics and inter harmonics in the multilevel inverter's output voltage. Phase disposition pulse width modulation (PDPWM) has the fewest harmonics. The inverter cells' power delivery is not equal in this manner. In the present paper, a strategy for improving sharing of power PDPWM for photovoltaic applications is proposed. The modified PDPWM is used on a 9-level inverter where each cell is connected to a PV array running at maximum power point tracking MPPT and under partial shadowing for single phase multilevel inverters. The MATLAB/SIMULINK software was used to do simulations, and the findings demonstrate that the method presented is effective at balancing the way power is shared between different inverter cells and reducing the voltage ripple of the DC link capacitor.</span>

Multilevel Inverter from a New Basic Unit

This research makes a novel suggestion for a cascaded single-phase multilevel inverter. The suggested basic unit is connected in series with this inverter, which can only create positive levels at the output. So, the recommended inverter is expanded upon by an H-bridge. This inverter is referred to as a developed cascaded multilevel inverter, and it allows the output of the architecture to have both even and odd voltage levels. Having fewer driver circuits, DC voltage sources and power switches is a benefit of the single-phase cascaded multilevel inverter that is built. In turn, this lowers the inverter’s cost as well as the size on installation. These features are acquired when comparing the proposed inverter with the conventional inverter.

Analysis and Experimental Validation of Selective Harmonic Elimination in Single-Phase Five-Level Inverter using Particle Swarm Optimization Algorithm

This paper presents the analysis and experimental validation of selective harmonic elimination in single-phase multilevel inverter using one of the most effective optimization algorithms known as particle swarm optimization. The presented inverter is one of the popular emerging topologies composed of a few switches compared to conventional topologies in order to produce a five-level output voltage. The optimization algorithm is applied to find the optimal commutation angles to implement the selective harmonic elimination by solving a system of transcendental non-linear equations. The results of the computational simulations are in good agreement with the theoretical analysis. The method is simple compared with the analytical methods, effective for driving the inverters and inexpensive to apply in real-time using a low-price DSP–Delfino-C2000-TMS320F28379D Chip. The theoretical analysis is verified by simulation using MATLAB/ Simulink environment and an experimental prototype composed of efficient electronic components, respectively. The obtained results of simulations and experiments confirm the effectiveness of the presented modulation method.

Development of an Enhanced Selective Harmonic Elimination for a Single-Phase Multilevel Inverter with Staircase Modulation

A low device switching frequency is recommended for the operation of multilevel inverters (MLIs) to achieve reduced switching losses. Selective harmonic elimination (SHE) and total harmonic distortion (THD) minimization are the two primary switching angle estimation methodologies for low-frequency modulation control. In this regard, a new generalized condition has been developed in this paper for the SHE technique. This original condition will give an output voltage with improved THD in comparison to the conventional SHE technique, while achieving its primary objective of eliminating the specific harmonic content from the output voltage. The proposed condition has been formulated by estimating the error associated with the staircase waveform and the desired sinusoidal output at the fundamental frequency. An infinite harmonic count has been considered for the evaluation of the quality of output, to obtain an accurate THD value without any underestimation. The proposed technique is analyzed, and its critical features are studied in Simulink. The effectiveness of the present work has been also validated by the experimental results.

A Study on Effects of Deadtime in a Single-phase Multilevel Inverter Using Circuit Topology and the Modulation Method

A Study on Effects of Deadtime in a Single-phase Multilevel Inverter Using Circuit Topology and the Modulation Method

MPPT and GMPPT Implementation for Buck-Boost Mode Control of Quasi-Z-Source Inverter

The focus is on the maximum power point tracking implementation for the buck-boost voltage mode control of a single-phase multilevel inverter based on a three-level neutral point clamped quasi-Z-source topology. To utilize shoot-through states only when boost function is needed and avoid it in the buck mode, two different control approaches are required. This article proposes merged control system which provides switching between different control algorithms in the buck and boost modes. In particular, a hysteresis band between the buck and boost modes is proposed which provides smooth and stable performance. It also includes features of the implementation of the global maximum power point tracking, which can scan the entire input voltage range in up to 10 s. Experimental results showed that proposed control system provides high and stable maximum power point tracking efficiency in different operation points. Finally, the key features are verified, the advantages, drawbacks, and an eventual potential for other applications are presented in conclusions.

Voltage THD limits for three- and single-phase multilevel inverters

Abstract This paper deals with single and three phase multilevel inverters power quality. The voltage total harmonic distortion rate is an important criterion for choosing the number of inverter levels and checking compatibility with power quality requirements. In this study, the author raises an interesting issue related to the definition of voltage THD boundaries with upper and lower limits. The problem is reformulated, and a novel and more practical approach is developed for three- and single-phase multilevel inverters. Found upper and lower voltage THD limits are sufficiently verified with most known switching algorithms like sinusoidal modulation (SM) with phase disposition (PD), space vector modulation (SVM) and selective harmonic elimination (SHE). They are also valid for cascaded (H-Bridge), neutral point clamped (NPC) and flying capacitors (FC) multilevel inverters.

Design and Control of a Decoupled Multichannel Wireless Power Transfer System Based on Multilevel Inverters

Traditional multichannel wireless power transfer (WPT) systems suffer from the complex system structure and cross-interference among receivers. To solve such problems, this article presents the design and control methods of a decoupled multichannel WPT system based on multilevel inverters. A single-phase multilevel inverter is utilized to drive the transmitter circuit with a voltage waveform consisting of multiple components. Particularly, these components are independent in the frequency spectrum, and their amplitudes can be controlled independently. Moreover, primary compensation is used to offer multiple frequencies for the primary circuit. Additional damping filters are used in the secondary circuits to reduce the cross-interference between the receivers. In addition, the features of the system topology are analyzed, and an exact parameter design method is presented. Furthermore, combined with the neutral point voltage balance strategy, a simple vector-based control method is proposed to regulate the transmitted power in each power channel. As a result, the power can be transferred to loads through the designed power channels simultaneously without mutual interference. Finally, both simulation and experiment of a 1-kW experimental prototype with SIC-MOSFET are given to verify the feasibility of the proposed multichannel WPT system and the control strategy.

A Generalized WECS System with Single Phase Multilevel Inverter having MPPT control with Neural Network

This paper describes the efficient MPPT tracking for variable wind speed using an artificial neural network. The neural network has been trained using the backpropagation algorithm and Levenberg-Marquardt (LM) based optimization technique to achieve maximum power point. A multilevel inverter having 10 switches has been used to reduce voltage stress, THD and switching losses resulting in improvement in performance and reduction in the driver circuit for the switches. The proposed system has been validated and simulated in SIMULINK/MATLAB

Design and implementation of reduced number of switches for new multilevel inverter topology without zero-level state

<p>Currently, multilevel inverter (MLI) has been chosen over conventional inverter because of less harmonic distortions and higher output voltage levels. In this paper, 15 level inverter with reduced number of power switching devices is designed. Different output voltage levels can be obtained including zero level or with none zero level (NoneZero level). Single phase MLI inverter with 7 switches is built, simulated, and implemented practically. The system depending on modified absolute sinusoidal pulse width modulation (MASPWM) controller strategy is adopted. Simulation results clarified that MLI with NoneZero level provides output voltage with total harmonic distortion (THD) percent less than with zero level. The THD of the 15 level output voltage with zero level is 3.39%, while with NoneZero level is 3%, respectively. The system is tested at different output levels. The THD values at different output voltage levels is reduced by 12% depending on NoneZero level state. Depending on what has been achieved, the system has been implemented practically with NoneZero<br />level and the THD value was 3.1%. These results prove the success of the suggested MLI circuit and MASPWM controller to obtain the required voltage level and THD.</p>

A 15-Level Switched-Capacitor Multilevel Inverter Structure With Self-Balancing Capacitor

In this brief, a new switched capacitor-based structure is presented for a single-phase multilevel inverter. The proposed structure is capable of boosting the input voltage and producing fifteen voltage levels at the output utilizing two separated DC voltage sources along with a switched capacitor unit. The proposed structure also has self-charging capability and can automatically adjust the capacitor voltage without any sensor. A quantitative comparison with similar structures has been performed to confirm the proposed structure. Furthermore, loss and thermal simulations have been performed for the proposed structure. The functionality of the proposed structure is examined by the simulation results. Finally, a laboratory prototype is implemented to verify the effectiveness and accuracy of the proposed structure and its control method.

Control Strategy for Single-Phase Grid-Interfaced Modified Multilevel Inverter Topology for Distributed Power Generation

In this article, a multiresonant proportional-resonant (PR) controller-based current controller is presented for a single-phase multilevel inverter topology, enabling grid-current injection into the distribution grid at unity power factor. The multiresonant PR-controller compensates third and fifth harmonic components to improve the harmonic spectrum of the grid injected current. Moreover, to reduce the switching losses in the power electronics converter, the nearest level modulation technique has been adopted, increasing overall efficiency. Furthermore, a modified multilevel inverter has been presented for grid integration, which requires a reduced number of switching components and isolated dc sources. In addition, system stability and sensitivity analysis are presented to evaluate the performance of the controller. The proposed scheme reduces the harmonic content in the grid current and the steady-state error in the grid injected power. Furthermore, the multiresonant PR-controller and PI-controller performance is verified in terms of steady-state error and total harmonic distortion in the grid current. An experimental prototype of the 21-level modified multilevel inverter-based grid-connected system has been developed to validate the claim.

Selective Harmonic Elimination Based THD Minimization of a Symmetric 9-Level Inverter Using Ant Colony Optimization

This paper proposed a new topology of a symmetric single-phase multilevel inverter with the smaller number of semiconductor switches and optimized low-frequency control methods to optimize the Total Harmonic Distortion. A nine-level single phase output is obtained by eight number of active semiconductor switches, four diodes and four capacitors from two asymmetrical dc sources. The selected harmonic order in the output voltage is eliminated by the PWM (SHE-PWM) based on selective harmonic elimination. To optimize the switching angles, an ant colony optimization is introduced. The proposed SHE-PWM and ant optimization are implemented and tested for THD on the SIMULINK platform. The proposed approach offers less THD and is best suited to high-power applications with medium voltage.

Fuel Cell-Based High-Gain Boost Converter Fed Single-Phase Multi-level Inverter Controlled by FPGA controller

For grid-connected applications, Multi-level Inverters (MLI) are mostly used, similarly to join the various RES to the grid as well as to satisfy the load demand MLIs are mostly preferred. This article presents a fuel cell-based high-gain boost converter with a single-phase five-level inverter controlled by CB-PWM techniques. A fuel cell produces a very less amount of power so to boost-up the fuel cell power to the essential power level with the help of a high-gain boost converter. The boost converter produces the required DC output power and that power is a converter to required AC power by using a single-phase five-level inverter. The MLI switches are controlled with the help of MC-PWM techniques and observe the inverter behavior in terms of THD, output ripples, and settling time. The entire work is done in MATLAB/Simulink tool as well as design a small prototype model by using the FPGA board.