Phase Opposition Disposition PWM Research Articles

Phase Shift APOD and POD Control Technique in Multi-Level Inverters to Mitigate Total Harmonic Distortion

Multi-level inverters are widely employed to generate new energy because of their huge capacity and benefits in sound control performance. One of the critical areas of study for multi-level inverters is control strategy research. In this study, the control strategy for a multi-level inverter—which is frequently employed in HVDC and FACTS systems—is designed. An asymmetrical D.C. voltage source is supplied to create the appropriate output voltage waveform with fewer total harmonic distortions (THDs) at the output voltage and current waveforms. In this work, the pulse width modulation techniques of POD (phase opposition disposition) and APOD (alternative phase opposition disposition) MC PWM are applied to a multi-level inverter to generate the seven-level output voltage waveform. This study presents an enhanced variable carrier frequency APOD control approach that can successfully lower the overall harmonic distortion rate. The design and completion of the phase-shifting POD and APOD control strategies are followed by an analysis and comparison of the THD situation under various switching frequencies and a simulation and verification of the control strategy using MATLAB simulation. The TI DSP-based control approach has been programmed. The APOD technique increases the output voltage’s THD to 18.27%, while the output current waveform’s THD is reduced to 15.67% by utilizing the APOD PWM technique. Using the POD PWM approach increases the total harmonic distortion (THD) of the voltage waveform by 18.06% and the output current waveform’s THD by 15.45%.

A Fifteen-Level Reduced Switch Count Multilevel Inverter with Multicarrier PWM

A multilevel inverter performs a major role in increasing the range of the level of output voltage without the use of a transformer in the power sector. Here an asymmetrical 15-level multilevel inverter fed from three unequal voltage sources has been proposed. The various modes of the conduction of the eight switches with the switching pattern are discussed with the circuit’s operation. The performance of the circuit is analysed using various techniques under MC-PWM methodologies such as Phase disposition (PD) PWM, Alternate POD (APOD) PWM, and Phase Opposition Disposition (POD) PWM. Key Finding: The logical expression used for generating the pulse pattern of the above techniques using the level shifting PWM technique to reduce the harmonics is performed, simulated, and compared by implementing three techniques for linear and non-linear load. The performance in terms of THD of output voltage under various modulation indexes is compared for various Llvel-shifting techniques. The performance of this 15L-MLI is simulated using MATLAB/Simulink and implemented in a prototype hardware model.

A performance assessment of nine-stage ternary DC source mli through various PWM topologies

ABSTRACT In modern days, MLIs comprise a lot of concentrations in academia and industry. As they are altering interest in a feasible technology in supporting frequent applications of renewable energy conversion systems and drives, these huge power and medium/higher voltage applications and MLIs are extensively used as one of the sophisticated powers converter topography. The MLIs are divided into two types such as asymmetric and symmetric. MLIs of the asymmetric kind have more amount of output AC voltage stage with fewer DC input source voltage and switching components. In this research paper, asymmetric single-phase cascade full-bridge MLI is developed with carrier-based unipolar PWM techniques. This MLI can generate nine-stage of output AC voltage through eight switches and two input DC sources. It is tested through a variety of multicarrier unipolar PWM control combinations. The Phase Disposition (PD), Alternating Phase Opposition Disposition (APOD), Carrier Overlapping (COP) and Variable Frequency (VF) are all PWM control which included in support of preference of single-phase nine-stage ternary cascade multilevel inverters. With various modulation indices (ma), the harmonic substance of output AC voltage for each approach is observed and tabulated. The proposed design for generating nine-stage output AC voltage is demonstrated using MATLAB-SIMULINK and confirmed using a laboratory-based prototype model. The results show that the unipolar Alternating Phase Opposition Disposition PWM technique that provides a high-quality output voltage with less harmonic distortion. Besides, the performance of Carrier Overlapping PWM techniques is greater since it produces a superior fundamental RMS output AC voltage.

Analysis of Asymmetric Hybrid Modular Multilevel Topology for Medium-Voltage Front-End Converter Applications

Modular multilevel converters (MMCs) have been conceived as an alternative in front-end converter applications to enhance the converter system’s reliability, minimize total harmonic distortion, and improve power quality. These converters utilize several DC-link capacitors and power electronic switches, along with switches operating with high switching frequencies, to attain the desired characteristics. Thereby, this paper systematically proposes a novel three-phase asymmetric hybrid modular multilevel converter (AHMMC) for front-end converters used in lower-medium-voltage applications. The AHMMC configuration is based on a three-phase converter connected to a per-phase series arrangement with a cascaded converter module (CCM). The study investigates the AHMMC and proposes a control scheme, which minimizes the voltage range on switches and maintains the current to its reference value. Furthermore, the study also introduces an active balancing of voltage across DC-link capacitors based on the phase opposition disposition PWM (POD-PWM) method. Our new configuration has features such as low switching loss, reduced DC-link voltage, a wider modulation range for the unity power factor (PF), and low voltage and current harmonic distortion. The simulation results are added to verify the performance of the new AHMMC topology and the usefulness of the modular control scheme. In addition, a low-voltage laboratory prototype based on customized control and power boards is built to validate the proposed converter and its control scheme in practice.

Design and Development of N-Level Symmetrical Multilevel Inverter Topology with Reduced Switches

In this paper, 11-level multilevel inverter with reduced power switch configuration is developed and investigated. This proposed configuration can be extended for [Formula: see text] levels with the required number of power switches. Comparative analysis between the proposed multilevel inverter topology and well-known existing multilevel inverter topologies is carried out. Fundamental switching angle calculation for the power switches of the proposed topology has been optimized using black widow optimization algorithm technique and also the proposed topology has been tested with the classical multicarrier alternative phase opposition disposition PWM technique. To test the effectiveness of the proposed topology, different tests have been conducted such as testing with different modulation indexes, DC input voltages, load settings and voltage ride-through capabilities. This paper presents various simulation and experimental results under various operating conditions to prove the performance of the proposed multilevel inverter topology.

Analysis on three phase cascaded H-bridge multilevel inverter based on sinusoidal and third harmonic injected pulse width modulation via level shifted and phase shifted modulation technique

This work proposes a comparative analysis of sinusoidal and third harmonic injected reference signal modulation accompany with level-shifted PWM technique named as phase disposition (LSPD), phase opposition disposition (LSPOD), and alternate phase opposition disposition (LSAPOD) and phase-shifted PWM technique. Switching pulses from both reference signal and PWM technique have been fed into three phase eleven level cascaded H-bridge multilevel inverter (CHBMLI) fed on a resistive-inductive load with the modulation depth (MD) set to varied from 80% to 100%. For voltage source inverter, total harmonic distortion (THD) content is critical and must be within the allowable range. To prove the feasibility of the reference signal with carrier signal schemes, the entire simulation of the modulation techniques is established and conducted via the Simulink environment. According to the analyzed result, the performance is acceptable in terms of %THDV and %THDI values. Simulation analysis also indicates, at full modulation depth, due to higher fundamental output voltage component produces via the THIPWM modulation technique compared to the SPWM technique, this causes higher %THDV value.

A Novel 9-Level Switched Capacitor Inverter Using Different Carrier Based PWM Techniques

In this paper, a new 9-level inverter employing switched capacitor technique is proposed. Three bidirectional voltage blocking switches are employed to connect the four H-bridges and to incorporate the three switched capacitors. The proposed multilevel inverter (MLI) circuit outputs a 9-level waveform with a maximum boosting factor of four. Unlike the already established switched capacitor based MLI consisting of two stages the proposed MLI is single stage inverter. The switches in the proposed MLI is subjected to a low value of voltage stress equal to Vdc. The proposed MLI is further analyzed by using various multicarrier sinusoidal PWM technique such as Phase Shift PWM (PSPWM), Phase disposition PWM (PDPWM), Phase Opposition Disposition PWM (PODPWM), Alternate Phase Opposition Disposition PWM (APODPWM) and Variable Frequency PWM (VFPWM).

Multicarrier PWM Strategies for Hybrid Symmetrical Multilevel Inverter with Reduced Switch Count

Multilevel inverters are widely used for high power and high voltage applications. The performance of multilevel inverters are superior to conventional two level inverters in terms of reduced total harmonic distortion, higher dc link voltages, lower electromagnetic interference and increased quality in the output voltage waveform. This paper presents a single phase hybrid eleven level multilevel inverter topology with reduced switch count to compensate the above mentioned disadvantages. This paper also presents various high switching frequency based multi carrier pulse width modulation strategies such as Phase Disposition PWM Strategy (PDPWM), Phase Opposition and Disposition PWM Strategy (PODPWM), Alternate Phase opposition Disposition PWM (APODPWM), Carrier Overlapping PWM (COPWM), Variable frequency carrier PWM (VFPWM), Third Harmonic Injection PWM (TFIPWM) applied to the proposed eleven level multilevel inverter and is analyzed for RL load. FFT analysis is carried out and total harmonic distortion, fundamental output voltage are calculated. Simulation is carried out in MATLAB/SMULINK.

Asymmetric hybrid multilevel inverter with reduced harmonic using hybrid modulation technique

<span>This paper studies the Asymmetric cascaded three phase multilevel inverter developed with hybrid modulation technique applied for an industrial application. The aim of this paper to reduce the Total harmonics distortion in the cascaded multi level inverter by introducing the new concept to develop the three phase CMLI. This inverter has two segments, one segment has H-bridge inverter and another segment has sequential arrangement of power semi conductor switches with asymmetrical voltage source in the ratio of 1:2. Similarly develop the segments for other phases. This new topology is called as Hybrid MLI. This hybrid MLI is used to reduce the no of semiconductor device requirement and the Total harmonics distortion. The inverter is controlled by Phase disposition (PD) and alternative phase opposition disposition PWM technique (APOD). This control technique is used to minimize the current harmonic and increase the system performance. The circuit is simulated using Matlab circuit and its performance is compared using PD and APOD PWM techniques and verified with simulation results.</span><p> </p>

Windowed PWM: A Configurable Modulation Scheme for Modular Multilevel Converter-Based Traction Drives

This article introduces a modulation technique for modular multilevel converter (MMC) in variable speed traction drives for electrical transportation referred as windowed pulsewidth modulation (W-PWM). The windowed PWM (W-PWM) is derived by blending the principles of operation of conventional modulation schemes for MMC based on the nearest level control (NLC) and on PWM with the aim of combining their inherent strengths and offering a higher degree of flexibility. This can reduce switching losses compared to classical PWM schemes and lower the current harmonic distortion compared to NLC schemes. The window in which the PWM is applied can be seen as an additional degree of freedom that allows a dynamic optimization of the performance of the traction drive depending on its operating characteristics. The performance of the W-PWM technique is assessed in this article for several operating conditions and compared with conventional schemes based on NLC and on the phase opposition disposition PWM with both numerical simulation and experimental verification on a small-scale prototype. Results demonstrate the flexibility of the W-PWM and its potential for applications in electrical traction drives.

Diminution of Harmonics in a Cascaded Multilevel Inverter using Third Harmonics Injection PWM Technique

This paper is deals the Asymmetric cascaded three phase hybrid multilevel inverter for ac motor application. This proposed hybrid three phase inverter is used to diminishes the no of semiconductor device requirement and enhances the power distribution of each H-bridge cell. The Third Harmonics Injection (THIPWM) with sinusoidal pulse width modulation (SPWM) are used to regulate the output voltage of the inverter, further incorporate the Phase disposition (PD) and Alternative Phase Opposition disposition PWM (APOD) techniques. This control technique is applied to minimize the current harmonic and get the better recital of the system. The circuit is simulated using Mat-lab Simu-link. The circuit performance such as THD, line voltage and phase voltage are compared using two hybrid modulation techniques and verified with simulation results.

A Six Level Diode Clamped Multi Level Inverter with APOD PWM

In this paper a six level diode clamped multi level inverter (DCMLI) with alternate phase opposition disposition (APOD) PWM technique is discussed and simulated using Matlab/Simulink. This DCMLI is capable of giving an output of six levels without a zero level. The six level consist of equal positive and negative level. The inverter uses five carrier waves, and one trapezoidal wave as the reference signal for pulse generation. The THD analysis for the same is carried out.

Comparison of Seven and Nine Level Flying Capacitor-Multilevel Inverter using Staircase and Stepped Modulation

In this paper, a seven-level and nine-level flying capacitor inverter (FLI) is modeled and simulated. For the control of the switches, distinct multicarrier PWM strategies such as In Phase Disposition (IPD) PWM, Phase Opposition Disposition (POD) PWM and Alternative Phase Opposition Disposition (APOD) PWM are implemented by considering three reference signals, namely sine, step and staircase. Intensive simulation experiments are carried out under matlab/simulink environment and fundamental value and harmonics of output voltages of the seven-level FLI and nine-level FLI under different modulation conditions viz., IPD, POD, APOD are measured and compared. Simulation results illustrates IPD and POD technique gives a better output waveform with lower THD value than APOD technique.

Extended Phase Opposition Disposition Pulse Width Modulation Technique for Cascaded 27 Level Inverter

The Extended Phase Opposition Disposition PWM (EPODPWM) technique has been applied in the two-level inverters successfully, but it is impossible to apply directly the EPODPWM technique to multilevel inverters. This paper proposes two kinds of EPODPWM techniques suitable for a cascaded multilevel inverter, analyzes the control strategy with the EPODPWM and obtains the design of its parameters. The simulation results show the proposed EPODPWM methods can get high magnitudes of the output fundamental frequency component, low total harmonic distortion and simpler digital implementation.

NPC Multilevel Photovoltaic Inverter with Nonlinear MPPT Using Boost Converter

This work proposes an advanced control of power converters used in photovoltaic solar energy. The boost converter and NPC three level inverter are usually associated with photovoltaic cells. A maximum power point tracking algorithm is adopted in this case to maximize the output power by using the sliding mode control approach. For three level inverter, five command strategy is applied in order to compare their performances: PDPWM (Phase Disposition PWM), PODPWM (Phase Opposition Disposition PWM), APODPWM (Alternative Phase Opposition Disposition PWM), COPWM (Carrier Overlapping PWM), PSPWM (Phase Shift PWM). The total harmonic distortion (THD) is evaluated for the various modulation index. Finally, validity and effectiveness are verified through a simulation in Matlab/Simulink.

Harmonic Analysis of Pulse Width Modulation-Based Strategies for Modular Multilevel Converter

MMC converters are an interesting solution for HVDC applications and renewable energy transport . This paper presents a mathematical analysis of the impact of various Phase Disposition PWM strategies on the circulating current which is one of the important MMC converter issues. The considered strategies are: Phase Disposition PWM (PDPWM), Phase Opposition Disposition PWM (PODPWM) and Alternative Phase Opposition Disposition PWM (APODPWM). Depending on the adapted modulation strategy, the proposed analysis proves that the circulating current varies from a DC component to a high current with high frequency components and a dominance of the second order harmonics. It is also demonstrated that PODPWM and APODPWM modulation strategies satisfy the balanced operation condition where only N sub-modules among the 2N available sub-modules are inserted into the phase leg and consequently ensure (N+1) voltage levels in the output voltage. Simulation results of a 2.7 MVA MMC converter are presented to verify the validity of the proposed methodology and analysis.

Bi-Directional Multi-Level Converter for an Energy Storage System

This paper proposes a 3 kW single-phase bi-directional multi-level converter for energy storage applications. The proposed topology is based on the H-bridge structure with four switches connected to the DC-link. A simple phase opposition disposition PWM method that requires only one carrier signal is also suggested. The switching sequence to balance the capacitor voltage is considered. The topology can be extended to a nine-level converter or a three-phase system. The operating principle of the proposed converter is verified through a simulation and an experiment.

Triphase Symmetrical Cascaded Multilevel Inverter (5L) for PV Systems Controlled by Various Multicarrier PWM Strategies

This paper presents a comparative study in the Matlab/Simulink environment among six multicarrier pulse width modulation strategies (MCPWM), of triphase symmetrical cascaded H-bridge multilevel inverter (five level). We will consider the Phase Disposition PWM, the Phase Opposition Disposition PWM, the Alternate Phase Opposition Disposition PWM, the Carrier Overlapping PWM, the Variable frequency PWM and the Phase Shifted Carrier PWM. Each type of these MCSPWM controls the same inverter. The symmetric voltage sources, supplying inverters cells are simulated using a DC voltage representing photovoltaic arrays (PV). Comparison of these MCPWMs is based on the spectral quality and magnitude of the output compound and simple voltages. The different strategies are carried out in Matlab/Simulink software environment with simulation results

A New Three Phase Seven Level Asymmetrical Inverter with Hybrid Carrier and Stepped Reference

This paper presents new hybrid modulation strategies for the chosen three phase seven level Asymmetrical Multi Level Inverter (AMLI) with Stepped reference. Performance indicesused are Total Harmonic Distortion (THD), Form Factor(FF),Crest Factor(CF),Root Mean Square(RMS) value of output voltage and DC bus utilization. The combination of inverted sine carrier and triangular carrier is used as hybrid carrier to produce triggering pulses for the power switches used in the proposed three phase seven level AMLI. This paper also investigates the potential of using hybrid carrier with the existing strategies such as Phase Disposition Pule Width Modulation (PDPWM),Phase Opposition Disposition PWM(PODPWM),Alternate Phase Opposition Disposition PWM(APODPWM)and Variable Frequency PWM (VFPWM) techniques for carrier. The simulation is done in MATLAB/SIMULINK and the results are presented for all modulation strategies. It is observed that hybrid PDPWM provides relatively better DC bus utilization and creates relatively less distortion for ma=0.7-1

A new three-phase 5-level current-source inverter

A new type of split-control three-phase 5-level current-source inverter (CSI) is proposed in this paper. The inverter is decoupled by the neutral line of the loads. Each phase of the inverter operates separately so that multilevel PWM technique can be applied to reduce output current harmonics. The digital multicarrier phase opposition disposition (POD) PWM signal generating technique is developed. The operation principle of the three-phase 5-level CSI using the new topology is analyzed by the simulations. An experimental prototype of a three-phase 5-level CSI has been built to practise the proposition in the paper.