Sinusoidal Pulse Width Modulation Research Articles

Current-Prediction-Controlled Quasi-Z-Source Cascaded Multilevel Photovoltaic Inverter

To address problems that traditional two-stage inverters suffer such as high cost, low efficiency, and complex control, this study adopts a quasi-Z-source cascaded multilevel inverter. Firstly, the quasi-Z-source inverter utilizes a unique impedance network to achieve single-stage boost and inversion without requiring a dead zone setting. Additionally, its cascaded multilevel structure enables independent control of each power unit structure without capacitor voltage sharing problems. Secondly, this study proposes a current-predictive control strategy to reduce current harmonics on the grid side. Moreover, the feedback model of current and system state is established, and the fast control of grid-connected current is realized with the deadbeat control weighted by the predicted current deviation. And a grid-side inductance parameter identification is added to improve control accuracy. Also, an improved multi-carrier phase-shifted sinusoidal PWM method is adopted to address the issue of switching frequency doubling, which is caused by the shoot-through zero vector in quasi-Z-source inverters. Finally, the problems of switching frequency doubling and high harmonics on the grid side are solved by the improved deadbeat control strategy with an improved MPSPWM method. And a seven-level simulation model is built in MATLAB (2022b) to verify the correctness and superiority of the above theory.

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.

A seven‐level switched‐capacitor based transformerless inverter with modified PWM strategy to enhance the performance of grid‐connected PV systems

AbstractAmong different types of transformerless photovoltaic inverters, multi‐level inverters based on switched‐capacitors (SC) are the burning topic of recent decades due to their potential advantages, such as, single source requirement, voltage boosting capability, and high power density. However, for a seven level output voltage, a conventional SC based inverter architecture uses more than two units of SC, a large amount of power switches, which then lead to capacitor voltage balancing problems. This paper presents a seven‐level switched‐capacitor transformerless inverter (SCTI), which is structured with only two SC units, ten power switches, and a single DC source. The proposed SCTI ensures voltage boosting capability, self‐voltage balancing, and low power semiconductor losses. Apart from these, a modified sinusoidal pulse width modulation (MSPWM) is also proposed in this work, which guarantees better thermal performance and low inverter output voltage THD for the proposed SCTI. The proposed SCTI along with the MSPWM is simulated in MATLAB/Simulink and PLECS computer simulation environments. A reduced scale laboratory prototype is also built and tested to ensure the feasibility of the proposed SCTI.

Comparison Between Hysteresis and Carrier SPWM Current Control Methods of Grid Tied PV Inverter

This paper has been studying two current control techniques for the two stages single-phase grid-tied photovoltaic (PV) inverter. These control techniques are Sinusoidal pulse width modulation (SPWM) and Hysteresis current. The whole structure of the grid-tied PV inverter has been studied in details for each of its parts. For comparison between the two techniques, the designed system has been tested under MATLAB/Simulink environment for different cases such as insolation and load variation. Results found that the Hysteresis current control method has a simple structure where it does not need PWM block, but it produces a higher total harmonic distortion (THD) as compared with the SPWM method

Output quality improvement for single‐phase inverter in V2G system

AbstractIn vehicle‐to‐grid (V2G) applications, a voltage source inverter (VSI) directly connects to a residential load or grid for DC/AC conversion and power flow control. In VSI, dead‐time is employed to prevent the breakdown of switching devices, however, the introduction of dead‐time leads to distortions of output voltage and current in both stand‐alone and grid‐tie modes. For the case of a power factor of 1, by analyzing the dead‐time effect of digital‐controlled double‐frequency sinusoidal pulse width modulation, a compensation amount is proposed to introduce in the modulation signals, the value of which is half of the delay register that generates a dead‐time of td. Moreover, considering the phase delay caused by hardware and software filtering in sampling, the grid‐tie mode control strategy based on dead‐time compensation is further proposed, which introduces the grid voltage as a feedforward signal. A 3.5 kW V2G experimental prototype is built and tested to verify the feasibility of the proposed strategies. The simulation and experimental results show that the proposed methods are effective for both modes, which improve the output distortion for different dead‐time without additional hardware circuits.

NOVEL SHUNT ACTIVE POWER FILTER BASED ON NINE-LEVEL NPC INVERTER USING MC-LSPWM MODULATION STRATEGY

This paper presents a novel shunt active power filter (Shunt APF) system based on a nine-level neutral point clamped (NPC) inverter, which can reduce current harmonics under various nonlinear loads. These loads can introduce harmonic currents within the system, which causes excessive power losses and alters the voltage systems' characteristics. Today, multi-level inverters are more suitable for high-voltage applications; their advantages are low harmonic distortions, low switching losses, low electromagnetic interference, and low acoustic noise. The reference signals required to compensate harmonic currents use the synchronous detection method (SDM) with phase disposition sinusoidal pulse width modulation (PD-SPWM) control due to its low complexity and superior performance. The proposed shunt APF configuration simulation is evaluated using MATLAB-Simulink and SimPowerSystem environment with inductive and capacitive non-linear loads. The simulation results show the efficiency of the proposed shunt APF in terms of harmonic compensation and power quality improvement. The results of comparative studies with other less multi-level inverters confirm the superiority of the proposed shunt APF system.

Multilevel Inverter with Enhanced THD Value used in Grid Connected Applications

In this work, the relationships among pulse width modulation (PWM), sinusoidal pulse width modulation (SPWM), and space-vector pulse width modulation (SVPWM) for three-phase inverters will be analyzed to better comprehend their differences. detailed comparison of the three modulation schemes under study’s Total Harmonic Distortion (THD). High-power applications are increasingly concentrating on converter technology. This growing importance may be attributed to its improved output waveforms over the 3- carrier-based sinusoidal pulse width modulation (SPWM). To control and modulate multi-level inverters, many techniques are employed. These methods are categorized based on how frequently they switch. The ripple current rating, capacitance value, and voltage balance in the DC bus capacitors are all impacted by the pulse width modulation techniques. It is crucial to select the modulation method based on the current control requirements, as this determines the output voltage waveform’s harmonic content. SVPWM is gradually becoming more and more popular in industries because of its improved dc bus utilization and ease of digital realization. This work examines PWM, Sinusoidal, and SVPWM feeding a load connected to RL. Three different methodologies’ performances are compared as these methods are investigated through simulation with MATLAB/SIMULINK software.

An Improvised Modulation and Control Approach for Dual Active Bridge DC–DC Converter System

Aimed at the control and modulation of dual active bridge bi-directional dc (DAB-BIDC) converter, an unconventional approach is applied to explore its effect in symmetrical wave-based isolated dc-dc converters. The existing control schemes of DAB-BIDC converter with unified or optimal phase shift (UPS/OPS) modulation have the constraints like complex control schemes, light load efficiency, current stress, and reactive power. Since a 50 Hz, grid-connected conventional converter system uses the sinusoidal pulse width modulation method to minimize the requirement for passive filters. Similarly, this work investigates the same analogy for the high-frequency (HF) symmetrical wave converters to get effective modulation and control scheme for the DAB-BIDC converter. Furthermore, the proposed sinusoidal pulse width-phase shift (SPW-PS) modulation scheme has been implemented by the optimally derived control parameters using Lagrange's Multiplier Method (LMM) to minimize the reactive power flow and current stress reduction at the HF link. Therefore, the DAB-BIDC converter with the proposed modulation and control approach can be used for EV charging and solid-state transformers applications. Finally, the proposed work is validated using MATLAB simulation and experimental setup having turn ratio 36/12 V, fundamental frequency 5-kHz, and switching frequency 100-kHz for the experimental validation using OPAL-RT.

A grey wolf optimization-based modified SPWM control scheme for a three-phase half bridge cascaded multilevel inverter

The Multilevel inverter (MLI) plays a pivotal role in Renewable Energy (RE) systems by offering a cost-effective and highly efficient solution for converting DC from Photovoltaic (PV) sources into AC at high voltages. In addition, an innovative technology holds immense significance as it not only enables the seamless integration of PV systems into the grid but also ensures optimal power generation, thereby contributing to the widespread adoption of RE and fostering a sustainable future. This paper presents a modified sinusoidal pulse width modulation (SPWM) control scheme for a three-phase half-bridge cascaded MLI-powered PV sources. The selection of the MLI configuration is motivated by its reduced number of switching components, which enhances system reliability and simplifies experimental implementation. Compared to the SPWM schemes which require (m−1) carriers that make the generation of the pulse circuit very complex, the proposed control scheme requires only three signals: a carrier signal, a triangular waveform, and a modulating signal. This approach significantly reduces the complexity of control and facilitates practical implementation. The proposed control scheme simulation is verified using MATLAB/SIMULINK Software. The grey wolf optimization (GWO) algorithm is implemented to determine the optimal switching angles of the proposed control scheme. The Total Harmonic Distortion (THD) objective is selected to be the fitness function to be minimized for improving the quality of the output waveforms. For verification, the results of the proposed GWO-based modified SPWM control scheme are compared with those obtained using both the Particle swarm Optimization (PSO) and Genetic algorithm (GA) used in the literature. Simulation results declared that the proposed control scheme improves performance, especially THD which is minimized to 6.8%. Experimental validation has been conducted by building a laboratory prototype of the proposed system. The experimental and simulation results gave acceptable and limited convergent results considering the experimental difficulties.

A Fault-Tolerant Control Method Based on Reconfiguration SPWM Signal for Cascaded Multilevel IGBT-Based Propulsion in Electric Ships

Electric ships have been developed in recent years to reduce greenhouse gas emissions. In this system, inverters are the key equipment for the permanent-magnet synchronous motor (PMSM) drive system. The cascaded insulated-gated bipolar transistor (IGBT)-based H-bridge inverter is one of the most attractive multilevel topologies for modern electric ship applications. Usually, the fault-tolerant control strategy is designed to keep the ship in operation for a certain period. However, the fault-tolerant control strategy with hardware redundancy is expensive and slow in response. In addition, after fault-tolerant control, the ship’s PMSM may experience shock and overheating, and IGBT life is reduced due to uneven switching frequency distribution. Therefore, a stratified reconfiguration carrier disposition Sinusoidal Pulse Width Modulation (SPWM) fault-tolerant control strategy is proposed. The proposed strategy can achieve fault tolerance without any extra hardware. A reconfiguration carrier is applied to improve the fundamental amplitude of inverter output voltage to maintain the operation of the ship’s PMSM. In addition, the available states of faulty H-bridge are fully used to contribute to the output. These can improve the life of IGBTs by reducing and balancing the power loss of each H-bridge. The principles of the proposed strategy are described in detail in this study. Taking a cascaded H-bridge seven-level inverter as an example, simulation and experimental results verify that the proposed strategy, in general, has a potential future application on electric ships.

Performance Analysis of a Novel Multilevel Inverter with Reduced Number of Switches

Multilevel inverters (MLI) are important and widely accepted under DC to AC converter family for medium and low power applications. In the paper a “new inverter topology” for multi-level is developed. The primary purpose of the work is to reduce the switch count number for considerable level of output voltage and also to reduce gate drives required. It also aims at analysis of performance of proposed topology of new multilevel inverter. Output of fifteen stages is generated from the proposed topology. For which only eight switching devices, four diode and three asymmetrical sources are used. Thus, the space and cost for installation is reduced. The designed topology is simulated with normal “pulse width modulation (PWM)” as well as “sinusoidal pulse width modulation (SPWM)”. Both the Simulation results are discussed with respect to “output voltage, current, Total Harmonic Distortion (THD)”. A comparative study is also made between the topology developed with few other latest MLI topologies.

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.

BLDC Motor Speed Control with Digital Adaptive PID-Fuzzy Controller and Reduced Harmonic Content

Low power brushless direct current (BLDC) motors are used in many consumer appliances. These motors have a relatively high winding resistance and therefore current control loop can be avoided in some cases, but fast and accurate speed regulation can be still needed. To minimize harmonics and generated sound noise, improved sinusoidal pulse width modulation (PWM) has been tested in the paper. As the most suitable commutation type, the sine wave with the third harmonic component has been selected. This type of communication reduced the torque ripple of the motor. This paper analyses the possibility to improve traditional proportional-integral-derivative (PID) speed regulator with Fuzzy logic block. A simulation model of BLDC motor, inverter, speed detection circuit and controller have been created. Simulation results showed that by applying the Fuzzy-based PID controller, the transient time can be reduced from 0.2 s to 0.05 s and overshoot can be avoided in comparison with traditional PID controller. Experimental results show a significant improvement in the motor dynamics—the overshoot and transient time were reduced twice. The difference with simulation results and experimental ones can be explained by delays introduced by the microcontroller.

Design and implementation of grid tied high step-up DC-DC converter with switched capacitor

In this paper, the design and implementation of a three-phase grid-connected inverter coupled with a high step-up DC-DC converter with a switched capacitor is demonstrated. In this converter two capacitors are utilized with a coupled inductor. The charging of capacitors takes place parallel and discharging in series during switch off and switch on time respectively. The energization of the coupled inductor provides the high voltage gain. The passive clamp circuit is used to recycle the leakage energy of the inductor circuit. Therefore, the switch stress is reduced. This high gain converter is given DC input of 40 V and a high voltage 538 V obtained is supplied to the grid connected inverter which uses sinusoidal pulse width modulation (SPWM), to obtain 3phase line-neutral voltage of 415 V from inverter for grid synchronization. A high voltage gain of 13 and efficiency of 96% is obtained for different load and voltage variation. The modeling and the simulation are done using physical security information management (PSIM) software and all the results are presented in this paper.

A new single DC source five-level buck-boost inverter for single phase application

Recent decades have seen an amazingly fast development of inverter topology, including multilevel inverters. This kind of inverter typically functions as a buck converter; a boost converter is the reverse of this kind of inverter. The two inverters limitation to operating in either buck mode or boost mode is a negative. In this study, a five-level inverter that can operate in both buck and boost modes and only requires a single DC source input voltage is proposed. The suggested inverter will therefore have a large operational area. This new inverter's possible conduction modes are examined in order to determine the control system that will be used. A test based on computational modeling and hardware implementation is then conducted in the lab after the new control structure based on sinusoidal pulse width modulation is established. This new inverter can operate in five-level in a buck and/or boost converter in terms of the output voltage to the input voltage, according to the results of simulation and testing. The proposed new inverter outperforms traditional inverters that solely run on buck or boost.

Design of a novel control hysteresis algorithm for photovoltaic systems for harmonic compensation

Solar photovoltaic (PV) system design and integration with an existing AC grid is growing very fast in recent years and used by many of them as they are pollution-free, structure is limited and maintenance free. From the factors considering, the performance of PV system depends upon the inverter output voltage tested for linear, non-linear, with harmonic, and without harmonic loads. Generated due to the nonlinear loads. Better inverter control techniques are developed to maintain grid power quality. This article discusses the analysis and comparison of pulse width modulation (PWM) converters with unique and state of the art nonlinear control schemes and various modulation approaches. The primary objective of this research is controlling an active filtering hysteresis PWM converter with no sensors. A simple structure with hysteresis current control method total harmonic distortion (THD) is lower when compared with the sinusoidal pulse width modulation (SPWM) method. The said claims are supported by employing computer simulations using MATLAB/Simulink and different control approaches, such as proportional plus integral and artificial neural network controllers.

Design and development of photovoltaic solar system based single phase seven level inverter

For solar photovoltaic (PV) systems, an upgraded triple gain seven-level inverter that works both independently and while connected to the grid is proposed. The two-stage configuration of the system is boost cascaded. The first stage has a one switch improved gain converter (OSIGC) to increase and normalize the input direct current (DC) voltage, and the second stage includes a unique seven level alternating current (AC) is produced via a multilevel inverter (MLI) design with triple voltage gain. The proposed OSIGC is appropriate for a broad range of conversions. The voltage gain in MLI was achieved using switched capacitor techniques. The DC-DC converter can achieve a maximum voltage gain of twelve and the MLI can achieve a maximum voltage gain of three, resulting in a DC-DC-AC voltage that can reach 36. Maximum power point tracking (MPPT) technique based on modified perturb and observe (PO) is used in OSIGC to maximise PV module power utilisation, and MLI control utilises sinusoidal pulse width modulation (SPWM) realistically. For the purpose of analysing the suggested system, a 200 Watt prototype statel is created. With a total harmonic distortion (THD) of 0.181%, up to 92.12% of the converter system’s overall efficiency is possible.

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.

Fuel cell stack design and modelling with a double-stage boost converter coupled to a single-phase inverter

Abstract A comprehensive proton-exchange membrane fuel cell stack model was developed and integrated with a two-stage DC/DC boost converter. It was directly coupled to a single-phase (two levels—four pulses) inverter without a transformer. The pulse-width modulation signal was used to independently regulate every converter phase. The converter was modelled using a MATLAB®/Simulink® environment and an appropriate voltage control method. The analysis features of the suggested circuit were created and, through established experiments, the simulation results were verified. A single-phase (two levels—four pulses) inverter control circuit was tested and it produced a pure sinusoidal waveform with voltage control. It matches the voltage of the network in terms of amplitude and frequency. A sinusoidal pulse-width modulation approach was performed using a single-phase (two levels—four pulses) pulse-width modulation inverter. The results demonstrated an enhancement in the standard of the output wave and tuned the dead time with a reduction of 63 µs compared with 180 µs in conventional techniques.

A portable frequency‐domain electromagnetic detection system

SummaryFrequency‐domain detection stands as a critical method in remote geophysical exploration; however, its practical application is constrained by the considerable size of the requisite instrumentation. In this paper, we present a compact frequency domain electromagnetic detection system. The integration of intelligent power devices and a novel hardware architecture substantially diminishes the system's dimensions, thereby enhancing its portability. Furthermore, the system design incorporates sinusoidal pulse width modulation and digital phase‐locked amplification to ensure the efficacy of the proposed system. Both the transmitter and receiver system are constrained to dimensions smaller than 1.5 m. Subsequent experimental validation attests to the exemplary hardware performance of the proposed system, with the transmitting voltage of the transmitter circuit attaining 500 V, and the receiver circuit exhibiting a sensitivity as low as 10−8 V. Significantly, this design paradigm not only facilitates the integration of transmitter and receiver systems for frequency‐domain electromagnetic detection but also introduces novel prospects for the application of frequency‐domain electromagnetic detection methods across diverse fields.