Pulse Width Modulation Technique Research Articles

A new class of active impedance source inverter with low voltage stress on semiconductors

SummaryIn this paper, a new group of active impedance source inverters, along with a suitable control method based on the pulse width modulation (PWM) technique, is presented. The purpose of these inverters is to reduce the voltage stress on capacitors, diodes, and switches compared to other topologies. Using the proposed control method to produce the gate pulse of the switches, all operating modes of one of the proposed inverters, in two different operations (synchrony and asynchrony), to calculate boost factor and critical inductance in the boundary condition, are analyzed. Furthermore, all equations of voltage and current of components to design the suitable amounts of capacitors and inductors are calculated. Then, the comparative analysis from different points of view, such as boost factor, total voltage blocked by diodes and switches, and voltage stresses on capacitors between the proposed topology and conventional structures to examine the advantages and disadvantages, is done. Also, the losses and efficiency of the proposed topology at different loads are fully given. Finally, a prototype of the proposed topology is designed, and its experimental results are provided to check the performance and correctness of the obtained equations in different operating modes.

A Wireless Potentiostat Exploiting PWM-DAC for Interfacing of Wearable Electrochemical Biosensors in Non-Invasive Monitoring of Glucose Level

In this paper, a wireless potentiostat code-named ElectroSense, for interfacing of wearable electrochemical biosensors, will be presented. The system is devoted to non-invasive monitoring of glucose in wearable medical applications. Differently from other potentiostats in literature, which use digital-to-analog converters (DACs) as discrete components or integrated in high-end microcontrollers, in this work the pulse width modulation (PWM) technique is exploited through PWM-DAC approach to generate signals. The ubiquitous presence of integrated PWM peripherals in low-end microcontrollers, which generally also integrate analog-to-digital converters (ADCs), enables both the generation and acquisition of read-out signals on a single cheap electronic device without additional hardware. By this way, system’s production costs, power consumption, and system’s size are greatly reduced with respect to other solutions. All these features allow the system’s adoption in wearable healthcare Internet-of-things (IoT) ecosystems. A description of both the sensing technology and the circuit will be discussed in detail, emphasizing advantages and drawbacks of the PWM-DAC approach. Experimental measurements will prove the efficacy of the proposed electronic system for non-invasive monitoring of glucose in wearable medical applications.

Simulation and FPGA based Implementation of PI and Fuzzy Controllers for Cascaded Asymmetric Multilevel Inverter

The main objective of this work is to improve the performance of Multilevel Inverter by using the novel LS-PD- PWM and controlling technique instead of the existing approach. The proposed work focus on closed loop controller such as existing PI and Fuzzy Logic Controller for resistive load with Multilevel Inverter. The proposed Asymmetric fifteen level Inverter offers less THD and high frequency than the Asymmetric nine level inverter. Asymmetric multilevel inverter is used to reduce the switching losses and THD. In this work is the generation and implementation of Pulse Width Modulation (PWM) techniques using Field Programmable Gate Array (FPGA) for Multilevel Inverter. PWM can be generated via Microprocessors, Microcontroller, FPGA and DSP Processors. Higher density Programmable Logic Devices (PLD) such as FPGAs can be used to amalgamate large amounts of logic into a single Integrated. Pulse width modulation (PWM) is generally used in power converter control. To generate LS-PD- PWM by using FPGA, this occupies less memory capacity and accurate than conventional one. An efficient PWM generation technique is performed using FPGA for lower frequency applications. Simulation and synthesis is done by ModelSim6.3c and Xilinx10.1. Further, the Implementation is carried out by FPGA Spartan3 Xc3s50. Key Word: PWM, FPGA, PLD (Programmable Logic Devices), LS-PD-PWM

Asymmetrical multi‐level inverter by using space vector pulse width modulation technique for low and medium power applications

SummaryA DC to AC converter is developed in this paper. This proposes a single‐phase five‐level inverter is developed in such a way that one DC source is used. The structure of the inverter is modular and the capacitor has self‐voltage balancing capability, which eliminates the need for sensors or an additional control loop. This paper presents the schematic diagram of the proposed topology, principle of operation, and the concepts of sinusoidal pulse width modulation (SPWM) for single‐phase and space vector pulse width modulation (SVPWM) for three‐phase. To further prove the advantage, power loss, and parameter computations are calculated mathematically. Low‐voltage stress is achieved in the proposed topology because the blocking voltages of all the switches are constrained to the input voltage. A comparison table is presented between SPWM and SVPWM schemes in three‐phase inverter. The proposed asymmetrical five‐level configuration setup is constructed, and experiments are performed inside the laboratory. The controller of the converter has been implemented in the field‐programmable gate array (FPGA) platform. In order to confirm the viability of the suggested topology, experimental results are provided for single‐phase arrangement. By using the FPGA platform, real‐time implementation is done for a three‐phase inverter topology.

Review on various voltage stability issues in AC distribution network

With the rapidly depleting natural energy resources and increasing population worldwide, the calls for more energy demand have risen globally. In this vein, the world is transitioning from traditional to renewable energy sources (RES) to meet the required demands. However, the (RES), due to its variable nature, has voltage stability and power quality issues that need to get minimized to enhance the reliability of the (RES) system. This paper reviews the voltage stability and quality issues in the AC distribution system based on renewable energy sources (RES). Initially the renewable energy sources and problems associated with renewable energy sources are discussed. This article gives an overview of voltage control strategies based on local as well as communication-based phenomenon for distribution networks. In this review a hybrid solar photovoltaic and wind system is used to generate the power of 3-5 kW. A voltage controller topology is suggested using MATLAB/Simulink for enhancing voltage stability of the system. It is suggested that a voltage stability controller can be designed using recommended topology by using Arduino with pulse width modulation technique. Thus, by measuring and correcting real-time voltage instability values of the system, the system can be made more reliably secure, efficient, and stable than the previously proposed renewable AC distribution systems.

Two different controllers-based DPC of the doubly-fed induction generator with real-time implementation on dSPACE 1104 controller board

The direct power command (DPC) of the doubly-fed induction generators (DFIG) has garnered increasing attention due to its simplicity, ease of implementation, and fast dynamic response that distinguished it from other controls. Recently, nonlinear controllers have been suggested to improve the DPC robustness, in particular the minimization of the DFIG power fluctuations. In the present research work, two different controls are used to regulate the DFIG power, where the first is a traditional DPC and the second is the DPC based on neural super-twisting algorithm (NSTA) controllers. The NSTA controllers were used instead of hysteresis comparators in the DPC technique, and the pulse width modulation (PWM) technique was used as a suitable solution instead of the switching table to better manage the state of switches and simplify the control system. The proposed controls were investigated and implemented using Matlab software and Dspace 1104 card with different tests to determine the best control. Experimental and simulation results show the good efficiency of the NSTA controller in improving energy and current quality. Also, the comparison is made between both techniques and the other controls in terms of reducing current harmonic distortions and ratios of the DFIG power fluctuations.

COMPARATIVE STUDY OF TRADITIONAL PWM INVERTERS AND MULTILEVELS INVERTERS

The need of higher powers in electrical drives has forced the researchers to develop new power source possibilities. Multilevel inverters have been presented as a cost effective solution for various high voltage and high power applications including power quality and motor drive problems. The traditional pulse width modulated (PWM) Inverter does not completely eliminate the unwanted harmonics in the output waveform. Using the multilevel inverter as an alternative to traditional PWM inverters for electric motor drive applications is investigated. The concept of the Optimized Harmonic Elimination Stepped-Waveform (OHESW) technique for a multilevel inverter is presented. The effectiveness of this technique in minimizing the inverter switching losses and its output voltage harmonic content which cause reducing harmonic losses and torque pulsations of an induction motor fed form is investigated analytically. Comparison between the Selective Harmonic Eliminated PWM (SHEPWM) as a traditional PWM technique for three-level inverter and the OHESW technique for multilevel inverter with regard to the switching losses, harmonic distortion, additional harmonic losses in the motor and the pulsating torques is also presented.

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%.

Efficient control of three-phase cascaded multilevel Z-Source inverter using SHEPWM technique

This paper presents an enhanced control strategy for three-phase cascaded multilevel Z-source inverters, focusing on the implementation of Selective Harmonic Elimination Pulse Width Modulation (SHEPWM) techniques to improve efficiency. Z-source inverters are gaining prominence in various applications due to their inherent advantages, such as increased voltage boost capability and inherent shoot-through protection. However, achieving optimal control in cascaded multilevel configurations poses challenges that this study seeks to address. The proposed control strategy optimizes the switching patterns of the inverter, thereby enhancing its overall performance. It allows for precise control over the output voltage and reduces harmonic distortion, ensuring the inverter operates efficiently across varying load conditions. The research methodology involves a comprehensive analysis of the proposed technique, including its mathematical modeling and simulation using advanced software tools. Performance metrics such as total harmonic distortion, efficiency, and transient response are evaluated to quantify the improvements achieved. The results obtained demonstrate the efficiency of the proposed control strategy. This method significantly reduces harmonic distortion in the output voltage, leading to improved power quality. Furthermore, the efficiency of the inverter is enhanced, making it suitable for applications demanding high-performance power conversion.

Cascaded H–Bridge Multilevel Inverter: Review of Topologies and Pulse Width Modulation

Multilevel inverters (MLIs) have become more popular for medium-voltage and high-power applications. The cascaded H-bridge multilevel inverter (CHBMLI) is one of the three most popular topologies of MLIs. It was more reliable due to its fewer components per level. The number of possible output voltage levels is more than twice the number of DC sources, the most suitable topology for integration with renewable energy sources, easy to design, and has good performance with modularity. The main disadvantage of CHBMLI is the need for separate DC sources for each H-bridge. However, this can be considered as an advantage to be employed in renewable energy applications. This paper provides a review of CHBMLI topologies and pulse width modulation (PWM) techniques, including fundamental and high switching frequency techniques, such as selective harmonic elimination (SHE), space vector modulation (SVM), nearest level modulation (NLM), and Carrier-Based PWM.

Analysis of Different PWM Techniques for Enhanced Ultrahigh Gain Z-Network Topology

In these modern times, the Z-source inverters (ZSIs) have become a revolutionary invention ever since the year 2002. The pulse-width modulation (PWM) technique used for most of the ZSIs is simple boost control PWM (SBC-PWM), and the SBC-PWM implies for a greater voltage stress on the inverter bridge and provides less boost factor. Likewise, many topologies for the basic Z-source topologies are evolved, and different PWM techniques are applied to them such as maximum boost control (MBC), maximum boost control with third harmonic injection (MBC-THI), maximum constant boost control (MCBC), and constant boost control with third harmonic injection (CBC-THI). All these mentioned PWM techniques are compared, and the converter opted in this paper is an enhanced ultrahigh gain active-switched quasi-Z-source inverter (EUHG-qZSI). The comparisons discussed in this brief are bridge stress, voltage gain, and voltage boost variation under each control strategy implementation. The theoretical and simulation evaluation for the abovementioned findings is presented in this paper, and the best PWM among them is maximum boost control (MBC).

Optimal Hybrid Pulse Width Modulation for Three-Phase Inverters in Electric Propulsion Ships

Global interest in environmentally friendly ships has surged as a result of greenhouse gas reduction policies and the demand for carbon neutrality. Despite growing demand for electric propulsion systems, there is a lack of research and development on crucial components. Efficiency and stability are primarily influenced by the performance of inverters, which are essential for driving propulsion motors. Existing inverter control techniques can be of two types: continuous-PWM (pulse width modulation) methods for harmonic performance enhancement and discontinuous-PWM methods for efficiency improvement by reducing losses. However, there are limitations in that each PWM method exhibits substantial variations in inverter performance based on its operating conditions. To address these challenges, this study proposes the hybrid pulse-width-modulation (HPWM) method for optimal inverter operation. By analyzing the inverter’s operating conditions, the proposed HPWM method adopts various pulse-width-modulation (PWM) strategies based on a modulation index to achieve harmonic improvement and loss reduction. Our focus is on comparing and analyzing diverse PWM techniques under varying modulation indices and frequency conditions to attain the optimal operating conditions. Experimental validation of the proposed method was conducted using a 2.2 kW dynamometer. In comparison with existing PWM methods, the proposed method demonstrated superior performance.

Seven‐level single‐source switched capacitor inverter with triple boosting capability and high reliability

SummaryA single‐source switched capacitor multilevel inverter (SCMLI) topology utilizing only 10 switches and 1 diode with the capability of generating seven output voltage levels and a triple voltage boosting factor is proposed in this paper. The converter has capacitors that are self‐balanced and do not require any additional circuitry. The multicarrier sinusoidal pulse width modulation (PWM) technique is used to generate various switching signals for the 10 switches. Moreover, the reliability analysis using the Markov model has been carried out to assess the lifespan of power electronic components used in the proposed converter. The converter's performance is analyzed when an open circuit fault occurs in one or multiple switches. Power loss and efficiency in the converter are calculated by PLECS software using thermal modeling. The efficiency of SCMLI was found to be 97.6% for a 300 W load. The inverter working is verified by building a 500 W prototype in the lab. The experimental results in steady‐state and dynamic conditions agree with the theoretical and simulation analysis.

A High-Resolution LED Stimulator for Steady-State Visual Stimulation: Customizable, Affordable, and Open Source.

Visually evoked steady-state potentials (SSVEPs) are neural responses elicited by visual stimuli oscillating at specific frequencies. In this study, we introduce a novel LED stimulator system explicitly designed for steady-state visual stimulation, offering precise control over visual stimulus parameters, including frequency resolution, luminance, and the ability to control the phase at the end of the stimulation. The LED stimulator provides a personalized, modular, and affordable option for experimental setups. Based on the Teensy 3.2 board, the stimulator utilizes direct digital synthesis and pulse width modulation techniques to control the LEDs. We validated its performance through four experiments: the first two measured LED light intensities directly, while the last two assessed the stimulator's impact on EEG recordings. The results demonstrate that the stimulator can deliver a stimulus suitable for generating SSVEPs with the desired frequency and phase resolution. As an open source resource, we provide comprehensive documentation, including all necessary codes and electrical diagrams, which facilitates the system's replication and adaptation for specific experimental requirements, enhancing its potential for widespread use in the field of neuroscience setups.

A New Design of UPQC-Based Hybrid Multi-Carrier Modulation for Transformer Less Grid Connected PV-Based Active Power Filter

In recent times, there has been a growing concern over the augmented power consumption, leading to a pressing need for compensating devices to maintain power quality in grid-connected systems. One extensively employed solution is the Unified Power Quality Conditioner (UPQC), which incorporates both shunt and series active power filters (APFs) connected through a DC-link capacitor. However, traditional systems using compensating devices can be costly and cumbersome, often relying on transformers to interface with the grid. To address these drawbacks, this report proposes a transformer-less networking approach using a multi-level inverter (MLI) that reduces the number of switches in the shunt and series APF. To enable the efficient operation of the MLI in UPQC, the report utilizes Synchronous Reference Frame Theory and Hybrid Multi-Carrier Pulse Width Modulation (H-MCPWM) techniques for reference signal generation and gate control, respectively. MATLAB/Simulink simulation version 2019a is employed to validate the performance of the proposed system, along with a hardware prototype featuring a motor load. A key aspect of the investigation involves conducting harmonic analysis for various modulation indices with a non-linear load. The resulting data is then compared to the outcomes of the conventional model. By exploring this approach, the report aims to showcase the viability of the transformer-less networking of MLI in UPQC, thereby paving the way for more cost-effective and efficient grid-connected systems with improved power quality.

Comparative Analysis of PWM Techniques for Interleaved Full Bridge Converter in an AC Battery Application

The AC battery utilizing second-life time batteries has gained great interest currently with the advantages of both power solutions and economic benefits. In this system, the power converters play a crucial role in the stable and effective operation of the system. This paper focused on the AC/DC stage with the chosen topology being the interleaved full bridge (IFB) converter due to its flexibility and the ability to increase the power rate of the system. For the sake of high-performance operation, various pulse width modulation (PWM) methods for this converter are analyzed. First, based on the theory of the traditional PWM methods for a full bridge inverter in combination with the interleaved technique, this paper proposed three interleaved PWM methods for the IFB converter. Secondly, the proposed methods are theoretically compared in terms of the output current, common-mode voltage, and power losses. Finally, the evaluation is carried out by both the simulation and the experimental prototype, in which the results are in good agreement with the theoretical analysis.

An asymmetrical multilevel inverter with minimum voltage stress and fewer components for photovoltaic renewable-energy system

Abstract The enhanced power quality provided by multilevel inverters (MLIs) has made them more appropriate for medium- and high-power applications, including photovoltaic systems. Nevertheless, a prevalent limitation involves the necessity for numerous switches and increased voltage stress across these switches, consequently increasing the overall system cost. To address these challenges, a new 17-level asymmetrical MLI with fewer components and low voltage stress is proposed for the photovoltaic system. This innovative MLI configuration has four direct current (DC) sources and 10 switches. Based on the trinary sequence, the proposed topology uses photovoltaics with boost converters and fuzzy logic controllers as its DC sources. Mathematical equations are used to calculate crucial parameters for this proposed design, including total standing voltage per unit (TSVPU), cost function per level (CF/L), component count per level (CC/L) and voltage stress across the switches. The comparison is conducted by considering switches, DC sources, TSVPU, CF/L, gate driver circuits and CC/L with other existing MLI topologies. The analysis is carried out under various conditions, encompassing different levels of irradiance, variable loads and modulation indices. To reduce the total harmonic distortion of the suggested topology, the phase opposition disposition approach has been incorporated. The suggested framework is simulated in MATLAB®/Simulink®. The results indicate that the proposed topology achieves a well-distributed stress profile across the switches and has CC/L of 1.23, TSVPU of 5 and CF/L of 4.58 and 5.76 with weight coefficients of 0.5 and 1.5, respectively. These values are notably superior to those of existing MLI topologies. Simulation results demonstrate that the proposed topology maintains a consistent output at varying irradiance levels with FLCs and exhibits robust performance under variable loads and diverse modulation indices. Furthermore, the total harmonic distortion achieved with phase opposition disposition is 7.78%, outperforming alternative pulse width modulation techniques. In summary, it provides enhanced performance. Considering this, it is suitable for the photovoltaic system.

INSULATED GATE BIPOLAR TRANSISTOR TEMPERATURE CALCULATION USING SIMSCAPE/SIMULINK ENVIRONMENT WITH VARIOUS SWITCHING FREQUENCY

Because of developments in high-power converters, it has become crucial to investigate how effective inverter performance is. consequently, via being aware of the temperature value of the junction for the inverter switch. The rise in the switching frequency of the inverter, as well as the kind of control technique used, all have an impact on the value of junction temperature. The traditional methods for determining the junction temperature are imprecise and challenging to use. Therefore, a novel approach was used in this study to compute the junction temperature in a simple manner utilizing the MATLAB/Simulation SIMSCAPE environment. The junction temperature of the inverter's switches is easily estimated, where the heat conveyed over the layers of the IGBT can be indicated by using the simple thermal model of Foster. Because the semiconductors within the SIMSCAPE environment exhibit boosted design together with a direct thermal port. As a result, the estimation of the junction temperature is more precise and direct. This feature is only openable in the newest categories of the MATLAB program (2019-2023) This paper presents the losses formed in an Insulated Gate Bipolar Transistors, and thermal behavior analysis to represent IGBT's layers. The simulation included the influence of various operating switching frequencies on the temperature value of the junction. The results show that the temperature value of the junction increases as the switching frequency value increases and the Space Vector pulse width modulation technique has a value of junction temperature lower than the Sinusoidal pulse width modulation technique at the same switching frequency.

DESIGN AND CONSTRUCTION OF A 1.7KVA PURE SINE WAVE INVERTER USING PULSE WIDTH MODULATION TECHNIQUE

This project is targeted on the design and construction of 1.7kVA pure sine wave following the high demand of constant and pure electricity sources for consumer homes or small commercial. The inverter ensures clean pure solar energy is converted from DC sources to AC voltages that can be used in consumer devices. The methodology that was adopted to achieve this project construction is the pulse-width modulation technique, which ensures that DC signals is fed to a MOSFET driver circuit which then produces AC signals. This current is then stepped up by a transformer to produce the desired 220 volts AC output voltage. The transformer we used also ensures that the inverter system can take up a load of 1.7kva. We found out that most inverters in the market produce a modified sine wave signal, therefore we used capacitor filters to ensure we obtain a clean pure sine wave as our output. We recommend that consideration should be made to the load being used for the inverter to ensure it doesn’t exceed its capacity. Also, an improved IC and MOSFET system can be used to obtain smother AC results. The aims and objectives of this project were all achieved at the conclusion of the project.

Transformerless Inverter with Charge Pump Circuit Concept for PV Application

This paper introduces a new single phase transformerless photovoltaic (PV) inverter for grid connected PV systems using the concept of a charge pump. It consists of four power switches, two diodes, two capacitors and an LC filter at the output stage. The neutral of the grid is directly connected to the negative terminal of PV panel. This common ground creates a constant Common Mode (CM) voltage and zero leakage current. Meanwhile, the charge pump circuit generates the negative bus voltage for the inverter during the negative power cycle. A unipolar Sinusoidal Pulse Width Modulation (SPWM) technique is applied to the proposed inverter with three level output voltage to reduce the output current ripple and the filter requirements. The main advantages of the proposed inverter are (1) the negative polarity of the PV is directly connected to the grid, so the leakage current eliminated, (2) it has a compact size, (3) peak of output voltage is equal to input dc voltage (unlike Neutral Point Clamped (NPC) inverter, Active NPC (ANPC) and some topologies, which requires two times of the peak ac-voltage magnitude), flexible grounding configuration and high efficiency. The operating principle and analysis of the proposed topology are presented in details. Experimental results of a 500 W prototype are demonstrated to validate the proposed topology and the overall concept. The obtained results clearly verify the performance of the proposed inverter and its practical application for grid connected PV systems.