Multicarrier Pulse Width Modulation Techniques Research Articles

Multicarrier PWM techniques for three phase modular multilevel converter application in MRI systems

This research paper presents about the performance analysis of three phase modular multilevel converter with level shifted (phase disposition pulse width modulation) and phase shifted pulse width modulation (PWM) method. This research not only discusses the significance of different modulation procedures in the context of modular multilevel converters but also carefully evaluates each of their unique performance characteristics. This research is based on the fundamental creation of pulses and patterns that can only be acquired by comparing sinusoidal reference signals with triangular carrier signal. Both levels shifted (phase disposition) and phase shifted PWM procedures are used to calculate the phase output voltage of a converter at 2N+1 level. The output waveform is crucially shaped by these modulation techniques, which also ensure effective energy conversion and lower harmonic content. On the basis of the output voltage waveform's quality, the comparative research is conducted and simulated results were presented.

Cone-structured seven-level boost inverter topology for improvising power quality using online monitoring controller scheme for DSTATCOM application

In this article, a seven-level triple-time voltage-boosting topology (8S7L-TTB) is proposed, which has eight switches as the minimum. This topology is used as DSTATCOM to eliminate power-quality issues. In a three-phase four-wire distribution system, specific unpredictable issues have emerged through the increase of unbalanced linear and non-linear loads, which has caused various drawbacks such as voltage imbalance, poor voltage regulation, increased reactive components, and harmonics generation, through which the life period of the system has been minimized, undesirable heating has been produced, and the RMS voltage has been reduced. Hence, it is highly essential to eliminate the issues as mentioned earlier. In this research, a PV-based DSTATCOM is introduced for online-monitoring adaptive Chebyshev neural network controller with triple-boost inverter topology. The three-phase system’s D-Q components, which have been continuously extracted under instant-loading conditions, and the reference magnitude, have been compared through the proposed controller. The error signal is received from the adaptive Chebyshev neural network controller, through which the proposed inverter-switching devices are triggered with multi-carrier pulse width-modulation technique are used to compute the THD of 2.79%. Furthermore, this proposed seven-level inverter and controller have solved the aforementioned problems and maintained the floating capacitor’s voltage nearly as similar as the source voltage in different loading conditions to ensure the efficiency of the system is at 96.82%. To ensure its suitability in real-time, the proposed controller is simulated with MATLAB software and validated through the downscale experimental setup and the results are observed.

Review and design of modular multilevel inverter with modified multicarrier PWM techniques for solar PV applications

PurposeThese implementations not only generate excessive voltage levels to enhance the quality of power but also include a detailed investigating of the various modulation methods and control schemes for multilevel inverter (MLI) topologies. Reduced harmonic modulation technology is used to produce 11-level output voltage with the production of renewable energy applications. The simulation is done in the MATLAB/Simulink for 11-level symmetric MLI and is correlated with the conventional inverter design.Design/methodology/approachThis paper is focused on investigating the different types of asymmetric, symmetric and hybrid topologies and control methods used for the modular multilevel inverter (MMI) operation. Classical MLI configurations are affected by performance issues such as poor power quality, uneconomic structure and low efficiency.FindingsThe variations in both carrier and reference signals and their performance are analyzed for the proposed inverter topologies. The simulation result compares unipolar and bipolar pulse-width modulation (PWM) techniques with total harmonic distortion (THD) results. The solar-fed 11-level MMI is controlled using various modulation strategies, which are connected to marine emergency lighting loads. Various modulation techniques are used to control the solar-fed 11-level MMI, which is connected to marine emergency lighting loads. The entire hardware system is controlled by using SPARTAN 3A field programmable gate array (FPGA) board and the least harmonics are obtained by improving the power quality.Originality/valueThe simulation result compares unipolar and bipolar PWM techniques with THD results. Various modulation techniques are used to control the solar-fed 11-level MMI, which is connected to marine emergency lighting loads. The entire hardware system is controlled by a SPARTAN 3A field programmable gate array (FPGA) board, and the power quality is improved to achieve the lowest harmonics possible.

Performance Analysis of Five-Phase NPC MLI with Phase Shifting Carrier Pulse Width Modulation

The five-phase loads with Multi-Level Inverters (MLI) are preferred by industries in high and medium power applications due to lower switching loss, voltage stress across switches, etc. The controlling of a five-phase motor drive is done by Pulse Width Modulation (PWM) techniques. This paper discusses different multi carrier PWM techniques, such as Level Shifting Carrier (LSC) PWM and Phase Shifting Carrier (PSC) PWM techniques available for controlling the inverter drive. The simulation is carried out for all PWM techniques and load voltage, voltage THD, Common Mode Voltage (CMV), and DC-link voltages are noted and compared among the PWM techniques.

Implementation of multicarrier PWM based 7-level Z-source cascaded H-bridge inverter

This paper elucidates the realization of multicarrier pulse width modulation (MC-PWM) based 7-level Z-source cascaded H-bridge inverter. MC-PWM technique is developed to generate switching pulses for Z-source inverter; it leads to boost the inverter output voltage with help of shoot through mode of operation. The output of Z-source inverter is connected to 7-level cascaded H-bridge inverter. Cascaded H-bridge inverter system much suitable for AC load drive, high voltage and high power and industrial applications. This proposed system provides reduced total harmonic distortion, improved stepped output voltage and current, nearly sinusoidal output voltage and reduced voltage stress across the switching devices. The inductors and capacitors values are selected based on the boosting level of Z-source inverter. The simulation results of proposed 7-level Z-source cascaded H-bridge inverter with MC-PWM technique is verified using MATLAB/Simulink.

A novel selective harmonic elimination for duple voltage boosting nine level inverter topology with fewer switching components for renewable energy applications

ABSTRACT A multilevel inverter plays a predominant role in improving the performance as well as efficiency of the inverter. In this study, the proposed idea of the selective harmonic elimination (SHE) for Duple Voltage Boosting nine-level inverter topology with fewer switching components possesses two times better voltage boosting capability than the considered conventional models. The proposed inverter comprises 12 power semiconductor switches, two capacitors, and a single diode, which is connected to a single dc (direct current) source. The duple 9-level topology has been studied and evaluated under different multicarrier PWM (pulse width modulation) techniques in order to obtain lw THD (total harmonic distortion), and the results proves that the Level Control PWM Technique exhibits a better THD value of 9.35%. To improve the quality of the output waveform, the SHE has been designed to fix the predominant harmonics so that the lower order harmonics are minimized to generate a lower THD. A detailed discussion has been made with the results of the proposed inverter THD, which are then compared with other nine-level inverters MATLAB/SIMULINK that has been used to perform the simulation of the duple model, and the obtained simulation results have been validated for different modulation indices. The FPGA SPARTAN 6E controller tests the experimental prototype of the nine-level inverter, and their cost function is represented in dollars, which is compared with the other similar nine-level inverters.

PWM control strategies for Switched-Capacitor inverters

A multilevel inverter is a power electronic device that is capable of generating alternating voltages of desired levels using several DC voltage levels. For high\\medium voltage and high-power applications, multilevel inverters are prominent because of their ability to operate at higher output voltage with very low input. They also give good quality output resulting in lower harmonic distortion within the output. In this paper, a new topology with switched capacitor inverter is proposed. This switched-capacitor is designed in such a way that only one DC voltage source is required to give voltage with triple gain. This paper presents the comparative study of various Multicarrier Pulse Width Modulation techniques with carrier signal based and modulating signal based. Performance factors like % THD and voltage stress across the switches are measured for various modulation techniques and therefore the results are studied. PWM method with the different carrier-based PWM such as sinusoidal PDPWM, PODPWM, APODPWM, VFPWM, COPWM, FFM and modulating signal based PWM such as Rectified Sinusoidal PWM, Trapezoidal PWM, THPWM, 60° Degree Modulated PWM has been analyzed. The simulations for switched-capacitor seven-level inverter using different modulation techniques are done with MATLAB/ SIMULINK 2017b.

A Comprehensive Review on Space Vector Modulation Techniques for Neutral Point Clamped Multi-Level Inverters

The Neutral Point Clamped (NPC) Multi-Level Inverters (MLI) have been ruling the power electronics industries for the past two decades. The Multi-Carrier Pulse Width Modulation (MCPWM) is common PWM techniques which are widely used in NPC-MLI applications. However, MCPWM is not having a good impact on the balancing of DC-link voltages, Common Mode Voltage (CMV) and limiting the Total Harmonics Distortion (THD). The Selective Harmonic Elimination (SHE) technique is introduced for reducing the THD, however all the switching angles should be maintained less than π/2 to keep the eliminated harmonics at constant level which narrows down the modulation index range. Hence, in recent days Space Vector Modulation (SVM) technique is widely used in NPC-MLI, which gives better DC-link voltage balancing, self-neutral point balancing, near-zero CMV reduction, better-quality harmonics profile and switching loss minimization. Hence, it is a preferred solution for the majority of electrical conversion applications such as electric traction, high power industrial drives, renewable power generation, and grid-connected inverters, etc. The paper gives a comprehensive review of the SVM for NPC-MLI. First, this paper deliberates the state of art for two-level SVM and extends it to three-level (3L) SVM. Also compares the 3L SVM performance with other MCPWM techniques. Followed by the various modified MLI SVM techniques in terms of their implementations, DC-link capacitor balancing, and reduction of CMV. Further, the review of MLI SVM is widened to open-end winding Inverters and multiphase MLIs. The final part of this paper discussed the future trends and research directions on MLI SVM techniques and its applications.

Design Level Shifted Multicarrier Techniques for Cascaded H-Bridge Sub-Multilevel Inverter

The key aim of this paper is to implement and analyze level-shifted multicarrier techniques in Cascaded H Bridge (CHB) - Sub multi-level inverter to produce multiple level output voltage. The multi-level inverter is to synthesize a near sinusoidal voltage from several levels of dc voltages. The asymmetrical DC voltage sources are used for CHB Sub-Multilevel inverter, and the 15-level output voltage is obtained. The asymmetrical DC voltage Sources 12V, 24V, and 48V are used to get the 15 Level output voltage. The multicarrier Pulse Width Modulation (PWM) is used to get the desired voltage at the output. The Level Shifted Phase Disposition (LSPD) and Level Shifted Phase Opposition Disposition (LS-POD) multicarrier PWM techniques are used to reduce the Total Harmonic Distortion (THD) in the output voltage. The circuit is developed and analyzed in MATLAB software. The THD, measured by using the FFT tool of MATLAB software From the simulated results, the level-shifted phase opposition disposition multicarrier PWM has better performance than level-shifted phase disposition multicarrier PWM technique because it contains fewer harmonics so to improve the system reliability and quality. The performance analysis and mitigation of harmonics can enhance the power quality of the supply voltage delivered to the customers. However, power quality occurs several problems such as voltage sag, swell, under-voltage, overvoltage, transients, etc.

THD Reduction in Multi Level Inverters based on Multicarrier Pulse Width Modulation Technique

Due to the advent of technology, electronic equipments are much more sensitive to harmonic and its analysis play an important role whereby reducing the distortion due to harmonics needs attention. To meet the requirements of the industries, harmonic free-high rating power sources are in high demand. Total Harmonic Distortion (THD) is an indicator of AC voltage source quality. In case of inverters, one such way to reduce THD would be the use of Pulse Width Modulation (PWM). The existing methods mainly use the low frequency pulse width modulation techniques for the switching. Control methods employing high frequency switching techniques held in controlling THD with proper application of filters. This paper analyses THD in multilevel inverters using multicarrier PWM technique with five pulse width modulation technique through MATLAB simulations. Finally, a comparison is done to find the less harmonic generated PWM method using fewerfilters.

Comparative Analysis of Multi-carrier PWM Methodologies for 3-Phase 9-Level Cascade Inverter

This work puts forth the comparative analysis of multi-carrier pulse width modulation (PWM) methodologies for 9-level cascaded H-bridge inverter. Multilevel inverters (MLIs) have many advantages over traditional inverters, especially for high power applications. The cascade-connected H-bridge multilevel inverters use capacitors and devices, requiring fewer components per level. Different sinusoidal PWM technologies are used to generate correlation pulses which control the converter switching. The simulation results show the relative performance of different multi-carrier PWM techniques in respect of output voltage waveforms. From the results, it is observed that in phase disposition (IPD) technique provides better performance and produces a substantially sinusoidal output voltage waveform vis-a-vis phase opposite disposition (POD) and alternate phase opposite disposition (APOD) techniques. Further, the total harmonic distortion (THD) is also reduced significantly and effective responses are obtained under varying modulation index.

A 7-level Inverter with Multi-Carrier Pulse Width Modulation Technique for PV Systems

This article presents a Seven –level Inverter with Multi-Carrier Pulse Width Modulation (MCPWM) technique for PV applications.it compares the three major topologies and their Total Harmonics Distortion (THD) for PV applications. Finally, the Cascaded H-bridge inverter is the best and recommend topology for PV applications. These are simulated in MATLAB-Simulink.

Novel neural network based speed estimator for multilevel inverter fed sensorless field oriented controlled IM drive

In this paper, a new reference model adaptive system based speed estimator is proposed for multilevel inverter fed sensorless field oriented controlled induction motor drive. The proposed scheme employs 2-neural network models which is novel in this paper. The proposed speed estimator is shown to overcome low speed problems. One of the FPGA implementation issues of NN model is the identification of appropriate bit precision. The performance of reference NN estimator is studied for various bit precision and the suitable bit precision is identified compromising the memory size (resource) and the accuracy. Further the suitability of multicarrier pulse width modulation techniques for multilevel inverter is also studied. The performance is compared in terms of magnitude of the output voltage and total harmonics distortion and suitable modulation technique is identified. The encouraging results obtained are presented.

Topology Using Cascade Multilevel Inverters With Minimal Switches

Since their inception in the late 1990s, multilevel inverters have experienced a number of modifications, some of which include novel topologies, control mechanisms, and modulation procedures. The most important reason for making such modifications was to reduce the burden on the system by getting rid of part of the switching components, while at the same time enhancing the resolution of the output voltage. In this research, a multilevel inverter and its ability to generate an output voltage spectrum consisting of seventeen discrete levels is investigated. The multilevel inverter in question makes use of eight switching devices. This configuration generates very little harmonic distortion because to the application of a multi-carrier pulse width modulation technique.

Opal-RT based Analysis and Implementation of Single Phase Cascaded Multilevel Inverter with Minimum Number of Switches

Objective: In this paper, the detailed analysis and performance of a single phase multilevel inverter topology is dicussed in order to produce a high quality of output voltage. Method: A seven level cascaded inverter topology having six switches is utilized to reduce the total harmonic distortion and the switching losses. This in turn reduces the overall cost of the system. The comparison between the proposed architecture and the existing architectures is done based on the power switches, DC voltage at the inputs, the number of clamping diodes and capacitors used. It is observed that the switch count is halved. Findings: Evaluation is done using phase disposition multicarrier pulse width modulation technique where all the carriers are in phase. Thus this technique is found to be capable of achieving minimum harmonic voltage distortion, thereby resulting in a nearly sinusoidal waveform. Improvements: The performance of the suggested topology is validated in real time environment using Opal-RT Lab simulator and adequate results were taken. The results obtained proved that by using lesser number of switches there is reduction in harmonic voltage distortion in comparison with the traditional multilevel inverter topologies.

Three phase z-source neutral point clamped inverter with multicarrier PWM technique

Purpose The purpose of this paper is to present the three phase seven-level Z-source neutral point clamped (NPC) inverter with multicarrier pulse-width modulation (PWM) technique. Despite numerous topologies and modulation methods, there is a dire need of developing PWM techniques that can be deployed in multilevel inverters. These inverters decrease the total harmonic distortion and it has a good performance for various electrical power system applications. The proposed inverter is investigated for its performance by executing it in shoot through and non-shoot through modes. Design/methodology/approach The purpose is validated through MATLAB/Simulink software platform for implementing the proposed seven-level Z-source NPC inverter outlined with multicarrier based phase disposition technique. The experimental results are verified using SPARTAN 3E FPGA controller with the same control strategy. Findings The efficiency of the proposed inverter is confirmed in terms of increased and faster conversion in the shoot-through mode. By using PDPWM technique the maximum boost gain is achieved with lower modulation index. High control of DC voltage is obtained with only one DC voltage source and one Z network. Originality/value Three phase multilevel inverters are widely used in improving the output voltage quality and reducing the encountered electromagnetic interference in electronic device or circuitry. They are employed in medium and high –power applications to attain increased power ratings while decreasing the switching losses. The performance results shown in this paper will satisfy the above needs of usage in certain applications and less switching losses.

Five-Level Reduced-Switch-Count Boost PFC Rectifier With Multicarrier PWM

A multilevel boost power factor correction (PFC) rectifier is presented in this paper controlled by cascaded controller and multicarrier pulse width modulation technique. The presented topology has less active semiconductor switches compared to similar ones reducing the number of required gate drives that would shrink the manufactured box significantly. A simple controller has been implemented on the studied converter to generate a constant voltage at the output while generating a five-level voltage waveform at the input without connecting the load to the neutral point of the dc bus capacitors. Multicarrier pulse-width modulation technique has been used to produce switching pulses from control signal at a fixed switching frequency. Multilevel voltage waveform harmonics has been analyzed comprehensively which affects the harmonic contents of input current and the size of required filters directly. Full experimental results confirm the good dynamic performance of the proposed five-level PFC boost rectifier in delivering power from ac grid to the dc loads while correcting the power factor at the ac side as well as reducing the current harmonics remarkably.

Opal-RT based Analysis and Implementation of Single Phase Cascaded Multilevel Inverter with Minimum Number of Switches

Objective: In this paper, the detailed analysis and performance of a single phase multilevel inverter topology is dicussed in order to produce a high quality of output voltage. Method: A seven level cascaded inverter topology having six switches is utilized to reduce the total harmonic distortion and the switching losses. This in turn reduces the overall cost of the system. The comparison between the proposed architecture and the existing architectures is done based on the power switches, DC voltage at the inputs, the number of clamping diodes and capacitors used. It is observed that the switch count is halved. Findings: Evaluation is done using phase disposition multicarrier pulse width modulation technique where all the carriers are in phase. Thus this technique is found to be capable of achieving minimum harmonic voltage distortion, thereby resulting in a nearly sinusoidal waveform. Improvements: The performance of the suggested topology is validated in real time environment using Opal-RT Lab simulator and adequate results were taken. The results obtained proved that by using lesser number of switches there is reduction in harmonic voltage distortion in comparison with the traditional multilevel inverter topologies. Keywords: Cascaded Multilevel Inverter, Multicarrier Pulse Width Modulation, Opal-RT, Sinusoidal Waveform, Total Harmonic Distortion

Multi Carrier based Multilevel Inverter with Minimal Harmonic Distortion

<p>This paper presents performance features of Asymmetric Cascaded Multilevel inverter. Multilevel inverters are commonly modulated by using multicarrier pulse width modulation (MCPWM) techniques such as phase-shifted multicarrier modulation and level-shifted multicarrier modulation. Amongst these level-shifted multicarrier modulations technique produces the best harmonic performance. This work studies about multilevel inverter with unequal DC sources using level shifting MCPWM technique. The Performances indices like Total Harmonic Distortion (THD), reduction of switches and number of DC Sources are considered. A procedure to achieve the appropriate level shifting is also presented is this paper.</p>

Performance Estimation of Multicarrier Based Multilevel Inverter

This paper presents performance features of Symmetric and Asymmetric Cascaded Multilevel inverter. Both the Phase shifted and level shifted multicarrier pulse width modulation (MCPWM) technique are used in MLI. The best harmonic performance is improved by Level-shifted multicarrier modulations technique . The objective of this work to propose MCPWM Technique for multilevel inverter with equal and unequal DC sources. The Performances indices like Total Harmonic Distortion (THD), reduction of switches and number of DC Sources is considered. An appropriate method to achieve the MC modulation technique is also presented in this paper.