Level Inverter Research Articles

Comparison of space vector and switching frequency optimal pulse width modulation for diode free F‐type multi level inverter

AbstractThis study presents a comprehensive examination of space vector pulse width modulation (SVPWM) and switching frequency optimal PWM (SFOPWM) for an F‐type multilevel inverter (FTMLI). SVPWM offers a simple, digital implementation for three‐phase, three‐level inverter structures, and carrier‐based SFOPWM allows for maximum use of switching frequency with a simple construction. This approach reveals the underlying relationship between the above two PWM techniques with various amplitude and frequency modulation indices to ensure the performance of FTMLI. A suitable comparative study was carried out to verify the PWM techniques based on the inverter output voltage, total harmonic distortion, switching stress, and filter size. The analytical conclusions are supported by the simulation results and their experimental validation.

Enhanced direct torque control based on intelligent approach for doubly-fed induction machine fed by three-level inverter

This paper presents an adaptive neuro-fuzzy inference system (ANFIS) based on 24 sectors direct torque command (DTC) for a doubly-fed induction machine (DFIM) by using a 3-level neutral point clamped inverter. The DTC approach is used in this paper with 24 sectors based on the ANFIS regulator to minimize the torque fluctuations, flux fluctuations, and stator stream THD (Total Harmonic Distortion) of the DFIM drive. The composed technique is accomplished by replacing the hysteresis controllers of the flux and torque with the ANFIS controller. On the other hand, the results of the designed approach based on ANFIS controls were obtained compared to the traditional approach that uses usual controls, as MATLAB was used to realize these approaches in different working conditions. In all tests, the designed method shows improved performance in minimizing torque and flux undulations while reducing the THD of the stator stream. These results highlight the extent of efficiency, high competence, and effectiveness in improving machine features compared to the conventional approach, where the designed approach minimized the THD of current by ratios of approximately 77.50%, 48.34%, 75%, and 81.43% in all tests. Also, the torque undulation value was reduced by 30%, 39.24%, 31.94%, and 59.31% in all tests compared to the DTC. The designed approach minimized the speed overshoot compared to the DTC by percentages estimated at 98.83%, 97.11%, 96.75%, and 95.56% in all tests. These percentages demonstrate the high efficiency and effectiveness of the 24 sectors DTC-ANFIS compared to the conventional approach in improving the features of the control system, making it a promising solution in all electrical fields in the future.

A Novel NR-DA-Based ANN for SHEPWM in Cascaded Multilevel Inverters for Renewable Energy Applications

Harmonics is the major power quality problem caused by nonlinear devices, leading to malfunction or operational halt of the system. Low-order harmonics increase vibration and heat generation in motors. Therefore, controlling harmonics in the output waveform is the prime target for industrial applications to avoid economic loss. Selective harmonic elimination pulse width modulation (SHEPWM) is one of the techniques used for eliminating or minimizing selected harmonics in the output voltage waveform. This paper utilizes the Newton-Raphson method and Dragonfly Algorithms to calculate optimum switching angles for a Cascaded H-bridge Multilevel inverter (CHBMLI). The algorithms use non-linear equations to calculate the Switching Angles of MLI. The Dragonfly algorithm requires several iterations to reach an optimum solution. For complex problems, this algorithm becomes computationally expensive and time-consuming. A lookup table addresses the limitation by offline training an Artificial Neural Network (ANN) to generate the optimum switching angle for a given modulation index. Neural Fitting Tool in MATLAB software is used to train the ANN model. The simulation is performed using MATLAB SIMULINK software for both 5-level and 7-level CHBMLI configuration. The Dragonfly algorithm-based ANN achieves THD 8.84% when the modulation index (M) equals 0.8 for a 7-level inverter and THD 14.91% for a 5-level inverter and effectively minimizes third and fifth-order harmonics.

Analysis of Cascaded H Bridge Multilevel Inverter for Three-Phase Induction Motor Drive

The last ten years have seen a rise in the usage of multilayer inverters. Because they can produce waveforms with a greater harmonic spectrum and reliable output. Several high voltages and high-power applications are suitable for these new inverters. A multilayer converter not only produce high power ratings, but it also saves time and money and enhances the system performance in terms of harmonics, dv/dt strains, and pressures on the motor bearings. Owing to its flexibility and modularity, the possible topology for a power application is the cascaded H-bridge multilevel inverter (CMI) with separated DC sources. This study investigates a cascade H bridge multilevel inverter, such as a Three, Five, Seven, Nine and Eleven level inverter in order to drive a three phase AC induction motor. A Level shifted Pulse Width Modulation (LSPWM) technique was applied for the CHBMLI. Specific emphasis is given to aspects like modulation and total harmonic distortion that are preferable or necessary for multi-level converters. For both intellectual and scientific considerations, investigating sine triangle carrier pulse width modulation is deemed to be the most auspicious approach. Analysis of the many performance parameters, including load torque, motor speed, and efficiency, an extensive survey is conducted. MATLAB / Simulink is built into the entire system, and simulation results are developed. The purpose of this research is to demonstrate the performance of 9-level and 11-level fed induction motor driving results for Electric Vehicle applications. CHBMLI fed motor drive is better suitable for Induction Motor Drives.

An innovative 11-level multilevel inverter topology with rotating trapezoidal SPWM for industrial and renewable applications

This paper provides a new, less complex multilevel inverter topology that can be used for industrial loads and renewable energy sources. The arrangement consists of eight switches to produce an 11-level output voltage with two uneven input sources. Moreover, it can be connected in a cascade to increase the output voltage and number of levels even further. Due to its control mechanism, which is based on the Rotating Trapezoidal Sinusoidal Pulse Width Modulation control method for creating a high-quality output voltage, the inverter’s key characteristic is its very low harmonic distortion of 3.45% at the output voltage when compared to the advanced triangular carrier-based PWM techniques of phase disposition sinusoidal pulse width modulation (PD-SPWM) it produces harmonic distortion of 11.38% at the output voltage, phase opposition disposition sinusoidal pulse width modulation (POD-SPWM) it produces harmonic distortion of 6.43% at the output voltage, alternative phase opposition disposition sinusoidal pulse width modulation (APOD-SPWM) it produces harmonic distortion of 6.69% at the output voltage, IN-Shift sinusoidal pulse width modulation (IN-shift SPWM) it produces harmonic distortion of 3.93% at the output voltage. This inverter is commonly used in wind turbines and solar cells. The schemes are implemented in MATLAB/SIMULINK and are validated with single-phase 11-level inverter implemented by using digital signal controller (DSC).

On Approach to Increase Integration Rate of p-n-junctions in the Framework of a Neutral Point Clamped Three Level Inverter

On Approach to Increase Integration Rate of p-n-junctions in the Framework of a Neutral Point Clamped Three Level Inverter

Performance of Integrated High Voltage Gain DC-DC Converter and Diode Clamped Multi Level Inverter with Renewable Energy Source in Standalone Applications

Performance of Integrated High Voltage Gain DC-DC Converter and Diode Clamped Multi Level Inverter with Renewable Energy Source in Standalone Applications

Fault Resilient Ability of Reduced Switches Multi Level Inverter for Off Grid Applications

Fault Resilient Ability of Reduced Switches Multi Level Inverter for Off Grid Applications

Single source self balanced switched capacitor based singe phase nine level inverter

Multilevel inverters are becoming increasingly significant due to their ability to efficiently convert power in various applications such as renewable energy systems, electric vehicles (EVs), and industrial drives. The growing need for efficient power conversion in these areas has driven heightened interest in multilevel inverters. High inrush current is required for numerous applications, including variable frequency drives, single-phase or three-phase machine drives, locomotives, electric vehicles. However, managing this inrush current is crucial to prevent damage to the power source and other connected equipment, as well as to ensure smooth and reliable operation. The solution for this is to provide isolation between load and source. The proposed single phase switched capacitor multilevel inverter possess the feature of virtual isolation between the load and the source. This topology consists of a switched capacitor cell network and a multilevel inverter. In this work, a simplest architecture is used for the MLI section to reduce the number of switches. The MLI section consists of only eight switches. Although the switched capacitor network in this topology consists of a higher number of switches, the switches in the network carry only very low current, resulting in negligible losses. Additionally, the switched capacitor network is highly modular in nature. The proposed single-phase inverter can be converted to a three-phase multilevel inverter (MLI) by connecting identical units in each phase, with the reference sinewave signal for the pulse-width modulation technique derived from the corresponding phases. Consequently, this proposed topology is suitable for both low-power and high-power applications. This work demonstrates that self-voltage balancing of the level capacitors can be achieved without the need for auxiliary components.In this design, the level capacitors act as the source to the load and are charged through switched capacitors. The voltage THD in the suggested work is less than 5%, which is in accordance with IEEE 519 standards. High voltage gain, better load, and line regulation, are other significant advantages of this novel topology. Another feature of this work is simplicity in design and can be easily extended to higher voltage levels. Comprehensive simulation and experimental results are provided to validate the precise performance of the proposed multilevel inverter

THD analysis of 15-level multilevel inverter using lesser number of switches with nearest level control technique

THD analysis of 15-level multilevel inverter using lesser number of switches with nearest level control technique

A level shift carrier based SPWM for reduced switch 5-level multilevel inverter topology

A level shift carrier based SPWM for reduced switch 5-level multilevel inverter topology

A Higher Level Inverter Fed Induction Motor Drive: Its Operational Challenges and PWM Solution

A Higher Level Inverter Fed Induction Motor Drive: Its Operational Challenges and PWM Solution

Machine learning based fault detection technique for hybrid multi level inverter topology

AbstractMultilevel inverters (MLIs) have a significant contribution in many industrial sectors due to their improved power quality and lesser voltage stress, over the conventional three‐level inverters. However, the implementation of MLIs with an increased device count creates the scope of development in MLIs topologies. In this regard, a hybrid MLI topology is studied in this paper whose architecture is based on conventional two‐level inverters. This topology has lesser device count characteristics when compared to conventional and most of the recently presented configurations for nine‐level output voltage generation. The major issue of capacitor voltage balancing is resolved by employing an appropriate switching strategy. However, the semiconductor switches are the most vulnerable components and causes the open circuit faults frequently that creates issues in real time operation. Hence, it is important to detect the open circuit fault in switches in the least possible time. A new approach to open circuit fault detection technique based on the analysis of load voltage waveform is proposed in this paper. The wavelet transform technique has been implemented for feature extraction of load voltage. Later, the classification of the fault has been achieved by training an artificial neural network (ANN). The proposed work has been studied in MATLAB/simulation and the obtained results are verified experimentally.

Dual tri-isolated DC H-6 inverter with minimal power components design

Multilevel inverters have been forecasted in recent years for industrial and renewable energy applications due to its inherent characteristics of shaping the output voltage nearer to sinusoidal shape through concatenating several two/three level inverters using isolated DC sources or DC-link capacitors. However, the classical topologies used for synthesizing stepped voltage have several outwards like more number of DC sources or DC-link capacitors and switching devices used. In this paper, an effort has been sighted to bring a new topology for generating stepped voltage to overcome the above mentioned demerits. In addition to this, a new digital pulse width modulation (PWM) strategy is developed in-line with a new topology to eliminate the use of carrier and reference signals. The performance of the proposed topology and developed control strategy are evaluated in MATLAB/ Simulink platform and an laboratory prototype is constructed for experimental investigations to accord the simulation results.

ADRC-LSE Control of a Dual-Star Induction Motor Powered by a Dual 3-level NPC Inverter

In the context of electric vehicle propulsion drives, this paper presents anActive disturbances Rejection Control (ADRC) strategyapplied to a Dual Star Induction Motor (DSIM)powered by dual 3 levels inverter type NPC. The proposed method focuses on enhancing the Active Disturbance Rejection Control (ADRC) method by integrating Least Squares Estimation, establishing a direct relationship between the control law and the necessary frequency for the DSIM to turn in the exact speed whatever the load torque applied. The ADRC with Least Squares Estimation is compared with Field-Oriented Control (FOC) to evaluate their performance in tracking reference speed and stabilizing time. Additionally, another test is conducted to assess the ADRC's ability to reject disturbances. Results from the simulation demonstrate the effectiveness of ADRC with Least Squares Estimation, showcasing its potential for optimizing DSIM control in electric vehicle applications, thereby contributing to enhanced efficiency and stability.

Predictive Controller Strategies for Electrical Drives System using Inverter System

Advanced control strategies in power electronics include Predictive controller of current (P CURRENT CONTROL) and Predictive controller of torque (P TORQUE CONTROL). In order to operate a SRM or an induction machine, the Predictive controller of torque (P TORQUE CONTROL) approach analyses the stator flux and electromagnetic torque in the cost function (IM), and the Predictive controller of current (P CURRENT CONTROL) method [1,2] takes errors between the current reference and the measured current into account in the cost function. The switching vector selected for usage in IGBTs reduces the error between the references and the predicted values. The system restrictions are easy to include [4, 5]. The weighting component is not required. Together with the P TORQUE CONTROL and P CURRENT CONTROL systems, the SRM method is the most practicable direct control technique since it doesn't require a modulator and offers 10% to 30% more power than an induction motor [3]. With the same current, an induction motor can only generate between 70 and 90 percent of the force generated by an SRM due to its lagging power factor. SRM approach decreases 23% more THD in torque, speed, and stator current when P CURRENT CONTROL and P TORQUE CONTROL method with 15-level H-bridge multilevel inverter is compared to P CURRENT CONTROL and P TORQUE CONTROL method with 15-level H-bridge multilevel inverter utilising induction motor [21]. The transistors are only swapped when necessary to maintain the limits of torque and flux, which minimises switching losses. To improve the efficiency of a multilevel inverter, semiconductor switches are switched in a specific pattern. In contrast to the P TORQUE CONTROL and P CURRENT CONTROL approaches using a 2-level voltage source inverter, the 15-level H-bridge multilevel inverter employed in this study, coupled with SRM and IM, gives outstanding torque and flux responses and achieves robust and stable operation. This unique strategy quickly caught the interest of academics due to its simple algorithm and high performances in both steady and transient modes [8].

Fuzzy Logic Control of Two-Stage Grid- Connected Photovoltaic System

In this paper, a two-stage grid-connected photovoltaic system is presented. The optimal performance of solar panels at varying temperatures and irradiance levels is achieved by the application of a fuzzy logic-based maximum power point tracking method. Space vector modulation is used to control the inverter; to achieve capacitor voltage balance, redundant switching states of a three level inverter are used. The grid side control regulates the power and the current injected to the grid, the conventional PI controllers are replaced by fuzzy PI. Simulations have been made using Simulink environment on MATLAB to validatethe control of the proposed system.

Squirrel Cage Induction Motor (SCIM) Rotor Flux Estimation and Observer Using Multivariable Sliding Mode Control (MSMC)

This paper proposes a multivariable sliding mode control (MSMC) based in rotor flux estimation and observer methods for squirrel cage induction motor (SCIM). The principle of sliding mode control (SMC) adjustment can also be applied to multivariable systems. In this case, for each control quantity, there is a control member who switches the latter quickly between a maximum value and a minimum value, thus causing the sliding mode to appear. This article will discuss sliding mode tuning of multivariable systems, highlighting issues that arise in relation to mono-variable systems studied so far. In this paper, we will establish the general relationships, where we introduce the regulators of multivariable systems. To describe the behavior in sliding mode, we will call or equivalent control vector, at the end of this article we will introduce a rotor flux observer to improve the results obtained. The work is developed with a 2-level voltage source inverter. The simulation results are carried out to verify and validate the multivariable sliding mode control method proposed based rotor flux estimation and observer scheme

Design DC/AC Converter for Renewable Energy Sources

Multilevel inverters are vastly used in power systems and “renewable energy sources” (RES) to provide an AC voltage with a low level of harmonic contents. This paper aims to design a 9-level inverter for RES such as photovoltaic (PV), wind turbines, and fuel cells… etc. The proposed inverter is constructed by 12 IGBT switching devices where all of which are powered by 4 DC sources of 81 V without balancing capacitors to make DC voltage 324 V. A Phase disposition (PD), alternative phase opposition disposition (APOD), and POD with a slight phase shift are the methods of modulations that are used to provide a sinusoidal waveform of the output voltage and current. The minimum “Total harmonic distortion” (THD %) of the output voltage of the inverter is 13.68 % and 1.7 % in the cases where there is no filter and with filter conditions respectively. The load voltage is regulated by a PI controller based on the RMS value of the inverter output voltage.

3-level inverter based compensator for power quality enhancement using proposed Trianguzoidal PWM technique

In today’s scenario, the integration of a grid-connected load system with a hybrid energy system (HES) is encouraged to improve the reliability of the system. With the stunning rise in nonlinear loads in HES over the last two decades, the power quality (PQ) of the system has emerged as a paramount concern in contemporary times. The power quality problems include the injection of harmonics in the source current, low input power factor, poor voltage regulation, the burden of reactive power, etc. So, to mitigate these power quality problems in a single-phase distribution system, a 3-level Cascade H-bridge (CHB) inverter-based shunt active power filter (SAPF) is employed alongside a proposed Trianguzoidal pulse width modulation (TRZ PWM) strategy. The single-phase distribution system with SAPF is simulated in fixed and dynamic load conditions to check the system’s efficacy. The proposed PWM techniques for SAPF are compared with conventional PWM techniques, i.e., level shift, phase shift, and hybrid PWM techniques. Results indicate satisfactory performance of the proposed PWM techniques, exhibiting low harmonic distortion in source current, well within IEEE 519 limits, and high active filtering efficiency (AFE) compared to conventional PWM methods. Furthermore, this paper provides detailed comparisons of conventional and proposed PWM techniques in the context of active & reactive power supplied or delivered by load, source, and compensator, input power factor, harmonics in source or grid current, AFE, and individual harmonic components concerning fundamental component of source current.