Phase Disposition Pulse Width Modulation Research Articles

Experimental Investigation of Modified Level Shift PWM with Capacitor Voltage Balancing on Single Phase Modular Multilevel Converter

Modular Multilevel Converters (MMCs) are a prominent voltage source converter topology that is rapidly gaining popularity in medium/high power/voltage applications, including high-voltage DC transmission systems and electric vehicle systems. However, MMC has the critical issue of unbalanced submodule capacitor voltages and circulating current. The MMC distributes DC-link energy evenly among its submodule capacitors, rather than storing it in a large capacitor like conventional voltage source converters. In MMC, the submodule floating capacitors interface the DC input voltage and AC output voltage. Therefore, capacitor voltages must be balanced. The existing capacitor voltage control struggles to handle many gate pulses at medium and high voltages. An effective control scheme is needed to solve the issues mentioned earlier. This paper presents a performance analysis of a 1-Φ MMC using a modified level shift PWM technique based on Universal Control Modulation Scheme (UCMS) and a sorting-based capacitor voltage balancing algorithm. MATLAB/Simulink software implements the proposed control method for a 1-Φ , seven-level MMC. The outcomes of the simulation demonstration reveal that phase disposition PWM offers less harmonic distortion of output phase voltage than the other level shift PWM techniques, such as phase disposition PWM and alternate phase disposition PWM. The simulation results also demonstrate the effective use of the sorting-based capacitor balancing algorithm to regulate the voltages of the submodule capacitors. Finally, the real-time GUI tool validates the simulation results using an experimental prototype of 1-Φ MMC with the dSPACE MicroLabBox 1202.

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.

Robust PWM control scheme for switched-capacitor MLI with leakage current suppression in grid-connected renewable energy application

Typically, parasitic capacitances exist between the ground and the solar panel terminals in grid-connected PV systems. These parasitic capacitances provide a path for a leakage current, which leads to significant safety concerns, observable and seriously hazardous harmonic orders aligned with the injected grid current, and significant safety difficulties. In this research, a robust PWM controlling method that used competently in reducing the level of the leakage current and improving the power quality of a switched-capacitor Multilevel Inverter. This technique creates developed reference signals from the main signal to generate the switching scheme for the converter circuit. Additionally, the suggested control strategy only works with a small number of carrier signals, resulting in a quick system response and a simpler controller algorithm. Likewise, this controlling approach offers a stable way to maintain a constant output voltage in the suggested converter by adjusting the switching capacitors' voltages, which is not possible with traditional control techniques. MATLAB/Simulink is used to simulate the outcomes for both the suggested control approach and the traditional Phase Disposition (PD) PWM control method whereas the leakage current component reduces to 25 % compared to the captured component with the PDPWM. The simulation and the practical results based on the dSPACE-1103 hardware are quite similar.

Multilevel inverter: harmonic analysis with and without filters for RL load using SPWM techniques

Multilevel inverter (MLI) gains more attraction compared to conventional inverter as it generates a staircase output voltage that mimics sine waves of desired output voltage. Cascaded H-bridge (CHB) topology is taken into consideration owing to several benefits over conventional inverters. Various levels of CHB (3 and 5 level) inverters are compared on diverse parameters. In this paper level shift sinusoidal pulse width modulation technique is considered resulting in reduced lower order harmonic (LOH) distortion and improve the quality of output current and voltage depending on the load. Since, the LOH are too dangerous for power electronic circuits. An attempt to shift all the LOH above 50th order depending on the modulation technique with analogy for selecting an appropriate switching frequency is highlighted. The effect of change in switching frequency and modulation index (MI) on RMS output voltage, % voltage total harmonic distortion (VTHD), output power factor with different modulation techniques such as phase disposition pulse width modulation (PsD PWM), phase opposite disposition (POD PWM), alternative phase opposition disposition (APOD PWM) is portrayed in the paper. Further, to boost the performance a unique filter circuits with optimal design values of Inductance and capacitance driven with IEEE 519-2022 standards. The effectiveness in terms of with and without filter is verified and validated using MATLAB.

Reduced Switch Multilevel Inverter Based Shunt Active Power Filter With ANN Controller for Power Quality Improvement

In order to improve power quality, this research investigates the use of SAPF with Seventeen Level Reduced Switch Multilevel Inverter. The electricity grid's stability is significantly influenced by various non-linear loads. To address this, SAPF is proposed and designed to monitor, manage the current movement between the power source and the load. The variance between the intended and real currents drawn from utility grid is assessed using p-q theory based hysteresis current controller. The calculated error current guides the controllers in forecasting the best-suited switching signals and modulation index for the seventeen level RSMLI-SAPF system. In this paper the traditional PI controller, Artificial Neural Network based controller are compared and the results are provided to validate the performance of SAPF. The proposed system is modelled and analysed using MATLAB/Simulink. The simulation results are provided for various modulation index using Hybrid Pulse Width Modulation in which Triangle saturated Phase disposition PWM using Unipolar Third harmonic injection as Reference is used and are subjected to non-linear loads.

Isolation‐based bidirectional generalized step‐up multilevel converter with optimized device count

SummaryThis article describes a generalized single‐phase multiwinding step‐up transformer‐based multilevel converter with optimized device count. The proposed topology comprises of a single dc source, eight switches (four unidirectional and four bidirectional) and a single high‐frequency multiwinding transformer. Phase disposition pulse width modulation (PDPWM) is used for the level creation. The proposed converter is examined qualitatively and quantitatively using the total number of transformers, PWM control method, switch count, voltage stress, and the number of gate drivers, all of which are favorable. All elements of transformer selection, winding requirements, and comparative study have been thoroughly examined. A thorough Lagrange multiplier method has been applied to minimize the copper losses and optimize the multiwinding transformer (MWT) winding. The proposed converter simulations are performed using the MATLAB/SIMULINK environment. Further, the validation of the result is confirmed by a hardware setup of 0.9 kW.

Power Losses Reduction of Stacked Multicell Converter Fed Wind Energy Conversion System (WECS) Using Hybrid Methodology

This paper proposes a hybrid method for reduction of power losses of multicell converter in wind energy conversion system (WECS). The proposed methodology is the Artificial Intelligence (AI) based phase disposition pulse width modulation (PD-PWM). The Artificial Intelligence (AI) is the Gradient Boosting Decision Tree algorithm (GBDT). Hence it is named as GBDT-PD-PWM. Gradient boosting is a machine learning system that creates a prediction model in the group of weak prediction models, often called decision trees. The multicell converter is employed as the grid side converter (GSC) of WECS to attenuate harmonics created by nonlinear load. For stacked multicell converters (SMCs), a method of capacitor voltage balance based on PD-PWM approach is proposed.

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.

Concert Exploration of DFIG Grid-integrated MMC using Artificial Intelligence

The performance of grid-connected wind turbine systems that use a Doubly Fed Induction Generator (DFIG) is explored in this work. In the suggested configuration, two conversion stages are present. In the first step, Alternating Current (AC) voltage is changed into Direct Current (DC) voltage. At this point, the conventional two-level converter is implemented. The second stage involves the conversion of DC to AC using a five-level Modular Multilevel Converter (MMC). Voltage fluctuation is observed in the DC link. It is anticipated that the Fuzzy Logic Control (FLC) approach will be able to adjust the DC link voltage at the MMC of the second stage of conversion. For the purpose of the Pulse Width Modulation (PWM) system, the current controller is accountable for regulating the current signals and the reference signals. As a result, the PI Controller (PIC) is being evaluated for use in this function. Carrier-based Phase Disposition (PD) PWM is employed for MMC switch control. The proposed controllers’ performance is validated in Matlab/Simulink.

Circulating Current Suppression Scheme for Interleaved Active Neutral Point Clamped Nine-Level Inverter

The interleaved active neutral point clamped nine-level (ANPC-9L) inverter can be used in 1500V photovoltaic power generation because of its advantages of low voltage stress, high equivalent switching frequency and small filter size. Circulating current between sub modules is a key problem for ANPC-9L. A simple scheme to realize circulating current suppression for ANPC-9L inverter is presented in this paper. The operation of the ANPC-9L is briefly discussed, and the model of coupled inductor is given. Analysis shows that the redundant working states of the inverter with same output voltage can be used to suppress the circulating current. Another objective is to analyze circulating current imbalance at the band transition when using phase disposition pulse width modulation (PD SPWM) strategy. A solution is proposed to cancel current imbalance. Simulation and experiment verify the effectiveness of the proposed strategy.

Design and Performance Analysis of New Multilevel Inverter for PV System

Multilevel inverters (MLIs) have recently attracted more attention in medium-voltage and high-power applications as they can provide an effective interface with photovoltaic (PV) systems. Conventional MLIs are used to generate higher voltage levels, which improve power quality and reduce the requirement for passive filters. However, recent research has focused on designing new MLI topologies using reduced switch counts and less voltage stress. This study, as such, proposes a new nine-level symmetric MLI for PV systems with a minimum number of switches. This decrease in the number of switches reduces the voltage stress across the switches and the number of driving circuits, which lowers the complexity of the control circuit and, as a result, lowers the cost and size of the system. This article compares the proposed MLI with other topologies based on the DC sources, switches count, gate driver circuits (Ngd), total standing voltage per unit (TSVPU), cost function (CF), and components count per level (CC/L). The proposed topology is integrated with the PV system. MATLAB software is used to evaluate the performance of MLI at step change in irradiance and under variable load conditions. The total harmonic distortion (THD) of the proposed topology is reduced with the implementation of phase disposition pulse width modulation (PD-PWM). In addition, PD-PWM is compared with phase opposition disposition pulse width modulation (POD-PWM) and alternative phase opposition disposition pulse width (APOD-PWM) modulation techniques. The simulation results reveal the improved performance of the proposed topology at variable irradiance and under varying load conditions. The comparison results reveal minimum (TSVPU), CC/L, CF, and switch count compared to existing topologies. Hence, the proposed topology of MLI is cost-effective and superior in all aspects compared to other topologies. In summary, it offers overall improved performance, and thus, it is feasible for the PV system.

Five-level cascaded H-bridge inverter for renewable energy applications

This paper presents a five-level inverter based on the phase-disposition pulse width modulation (PD-PWM) technique for renewable energy applications. The conventional cascaded H-bridge (CHB) five-level inverter structure is reproduced, and an LC filter is designed to get optimum results from the inverter output. Two batteries are used as renewable energy sources to investigate the performance of the designed inverter. The system can provide 220 volts and 50 Hz AC supply with a 6.9 kW power supply to the load/grid. The designed output is compared with filter and without filter circuit. It provides sinusoidal voltage and current output with a very low total harmonic distortion (THD) of 2.75% which is compliant with IEEE 519 standards. MATLAB/Simulink software tool is used for the entire design. The inverter’s output is graphically represented, and discussed various parameters like switching frequency, THD, modulation index, and rated voltage.

A Reduced Switch Count High-Frequency Single-Phase 5-L MLI for IH Applications

Nowadays, multilevel inverter (MLI)-based induction heating (IH) technology is the best-suited option in many domestic, commercial and medicinal applications because of its higher efficiency, low cost, fast heating and lower electromagnetic interference (EMI). This paper presents reduced components count high-frequency (HF) single phase five-level (5-L) MLI for IH applications. The working methodology of the proposed system has been analyzed in the multicarrier phase disposition pulse width modulation (MC-PD-PWM) method in high switching frequency i.e., 10[Formula: see text]kHz. In addition, the proposed topology can produce output voltage twice of input voltage without any external source. Moreover, the detailed power loss and reliability analysis have been evaluated for the proposed system. In terms of switch count and efficiency, the single-phase 5-L inverter architecture is compared to some conventional and current topologies. Finally, to validate and justify the operation of the proposed system, the simulation and experimental results of five-level inverter are presented.

Single‐phase five‐level common‐ground transformerless inverter using switched capacitors for photovoltaic application

AbstractTransformerless inverters (TLIs) are extensively used in the photovoltaic (PV) grid‐connected system. TLI with a common ground structure exhibits multiple excellent features that improve the efficiency of the inverter, eliminating leakage current and boosting the voltage. The use of TLI eliminates the electrical isolation required between PV and the grid, resulting in a leakage current (LC) issue. The LC affects the power quality of the inverter and creates a safety‐related issue. This paper presents a new TLI topology based on the common ground (CG) structure. This topology uses eight switches and two self‐balanced switched capacitors. Phase disposition pulse width modulation (PD‐PWM) control scheme is used to create a five‐level output voltage. Further, adequate analysis for component selection and loss analysis is carried out to evaluate the efficiency. Its CG configuration certifies that there is minimal LC and common mode voltage (CMV). It also supports the active and reactive power of the grid. Its dual gain makes it suitable for photovoltaic (PV) applications. This topology is simulated for leading, lagging, unity power factor (UPF), and changes in input voltage and load conditions. Later, a corresponding experimental test is carried out on a laboratory prototype (1 kW). An equitable comparison is carried out for the component, stresses, and features like CG, and LC, along with efficiency.

A new generalized floor function based high switching frequency modulation and control technique: Multilevel inverters

SummaryA new generalized floor function (F2) based single carrier pulse width modulation (F2SC‐PWM) technique has been proposed in this paper by considering a single‐phase 9‐level T‐type packed U‐cell (PUC) inverter topology. In literature, the conventional level‐shifted PWM technique requires (level‐1) carriers, and the unipolar phase disposition (UPD) PWM technique requires (level‐1)/2 carriers to produce a particular level of output. To reduce the complexity of control, the authors have developed single‐carrier‐based PWM techniques. However, these are not generalized in a simple manner and are especially applicable only to particular inverter topologies. In this paper, a new F2SC‐PWM technique with a single modulating signal has been introduced that is applicable to any multilevel inverter (MLI) topology. This technique is very simple to implement, and it does not internally require any large number of mathematical operations and if‐else loops. Finally, a laboratory prototype has been used to verify the operation of the 9L‐TPUC topology considering R and RL loads with respect to step change of load, step change of modulation index (MI), and step change of modulation frequecy (MF) via with new proposed control technique (PCT).

High‐gain nine‐level switched‐capacitor multilevel inverter featuring less number of devices and leakage current

AbstractIn this article, a novel switched‐capacitor multilevel inverter (SC‐MLI) for on‐grid and off‐grid applications with PV is presented. The nine‐level proposed SC‐MLI with simple architecture is produced gain of four times across the load voltage. Further, the proposed inverter needs only 10 power switches, a single dc source, three diodes, and three capacitors. For a suitable switching operation, phase disposition pulse width modulation (PD‐PWM) was developed. Furthermore, the capacitor inrush current, which is a major shortcoming of SC‐MLI, is mitigated in the proposed topology by employing a charging inductor. Furthermore, the proposed inverter is used as a single‐stage PV grid‐tied inverter. When inverter is used for PV applications, the proposed inverter provides minimum value of leakage current. In addition, to demonstrate the superior performance of the proposed switched capacitor MLI, a comparative analysis with an existing off‐grid and existing on‐grid SC‐MLIs is performed. A fully circuit has been simulated using Matlab/Simulink to test the effectiveness and feasibility of the proposed topology. The prototype of the hardware system is designed of a nine‐level proposed topology using the dSpace 1103 controller board to validate the results.

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>

A Single-Phase Common-Ground Five-Level Transformerless Inverter With Low Component Count for PV Applications

Multilevel inverters (MLIs) featuring reactive power ability and common ground (CG) have become much popular in transformerless grid-tied photovoltaic applications. A switched-capacitor (SC) based five-level transformerless inverter configuration is thus proposed in this article, which requires only six switches, one diode, three capacitors, and one input dc voltage supply. Notably, only four power switches are operated in high frequency, thus, the switching losses are reduced. Moreover, the presented topology can effectively tackle the leakage current problem using a CG architecture. A multicarrier phase disposition pulsewidth modulation strategy is employed to achieve reactive power regulation and SC voltage self-balancing. To achieve the neutral point voltage balance of the presented five-level inverter, a simple closed-loop voltage-balancing control method is proposed. The operation principles with modulation strategy and voltage self-balancing of SC are discussed in depth. Comparisons between the proposed and the state-of-the-art MLIs are presented in detail. Finally, experimental tests on a single-phase 1.1-kW prototype validate the appropriate performance of the proposed inverter.

A Three-Phase Dual-Output T-Type Three-Level Converter

A novel three-phase dual-output T-type three-level converter (DO-T-TLC) topology is proposed in this article. The proposed topology has the dc-link and two sets of three-phase ac voltage output terminals. The topology of DO-T-TLC is introduced. Then, the operating principle of multiplexing switches and the available switching states of converter are analyzed, including current path, output phase voltage level, and blocking voltage of different switching states. The phase disposition pulsewidth modulation scheme with dc offsets is discussed in detail, and the key problems of the modulation scheme under both the common frequency and different frequency operation modes, such as voltage level selection, displacement angle constraint, and modulation index range, are studied. For the imbalance of two series capacitors in the dc-link, the mechanism is first revealed, and then a dc-link capacitor voltage balance method to control the average neutral point current is proposed. When DO-T-TLC is used in different operation modes, the ability and effect of this method to balance capacitor voltages are summarized. A low-power three-phase prototype is built, and the experimental results are given to verify the feasibility of the proposed topology and the effectiveness of the modulation scheme to control the voltage balance.

Performance evaluation of seven level grid-tied PV inverter employs seven switches with the triple gain

Abstract In this paper, a novel switched capacitor converter has been proposed to generate 7-levels using seven semiconductor switches (7S7L) to get triple gain in the output voltage which is supplied by a single dc source. A PWM technique, phase disposition pulse width modulation (PD-PWM) has been designed to achieve a suitable switching operation for the 7S7L inverter. In addition, the capacitor voltage is balanced and the suggested inverter uses a charging inductor to decrease the capacitor inrush current, which is a shortcoming in the switched-capacitor multilevel inverters. Moreover, the 7S7L inverter is used to interface the solar panels with the utility grid using a synchronous reference frame-based controller. To check the efficiency, taking actual data, power loss calculation has been discussed for the 7S7L inverter. To illustrate the better performance of the proposed 7S7L inverter than the existing seven-level SC-MLI presented in the literature, a comparative study is also undertaken. To verify the feasibility and effectiveness of the proposed topology, a converter is simulated using Matlab/Simulink. To validate the simulation results, a real-time study is completed using the OPAL-RT 4510 real-time platform.