Pulse Width Modulation Control Research Articles

Efficiency of Series APF based on Nine-level NPC Inverter Compared to Seven-level Configuration

This article presents the performance comparison of Series Active Power Filter (Series APF) based on seven and nine multi-level Neutral Point Clamped (NPC) inverters using the same control scheme. The Series APF is one of the most efficient and effective modern custom power devices used in power distribution networks to compensate voltage harmonic and all voltage disturbances. The conventional configuration based on voltage source inverter (VSI) operated at very high switching frequency presents several drawbacks and limited for low power applications. To overcome these problems and improve the output voltage different multi-level are used in various power application in particular Flying Capacitor (FC), Cascade H-Bridge (CHB) and multi-level (NPC) inverters. In this study seven and nine-level (NPC) inverters are proposed for active power filtering system; these inverters present diverse advantages include the capability to reduce the harmonic content, decrease the voltage or current ratings of the semiconductors and mainly they can work at low switching frequency. To generate switching pulses Multi-Carrier Level-Shifted Pulse Width Modulation (MC-LSPWM) control technique is adopted with modified P-Q control strategies. To verify the accuracy and the performance of the proposed Series APF models, simulation is performed using MATLAB-Simulink platform and SimPowerSystem Toolbox. The obtained results show the superiority of series APF based on nine-level in term of THDv reduction compared to the systems with seven-level inverter topology.

Comparisons of Loss Reduction Techniques Based on Pulsewidth Modulation and Model Predictive Control for Three-Phase Voltage Source Inverters

Due to the lack of comparative studies between discontinuous pulse-width modulation and model predictive control methods for reducing switching losses in two-level three-phase voltage source inverter, a comparative analysis of a generalized discontinuous pulse-width modulation and two model predictive control approaches for reducing switching losses is studied in this paper. Both generalized discontinuous pulse-width modulation and two model predictive control approaches are described and conducted in the simulation and experiment. The output performance is obtained by these methods after conducting in various conditions, including switching frequency, output power, and load conditions. It is validated that the generalized discontinuous pulse-width modulation control scheme achieves a better control performance at steady-state, while two model predictive control schemes have better transient-state performance with a superior dynamic. Additionally, the generalized discontinuous pulse-width modulation approach achieves better reducing switching losses performance and has slightly higher efficiency than that of two model predictive control approaches.

Fractional-Order Linear Active Disturbance Rejection Control Strategy for Grid-Side Current of PWM Rectifiers

To further improve the performance of linear extended state observer (LESO), a novel fractional-order linear extended state observer (FOLESO) is proposed in this paper. By incorporating a fractional-order term into the framework of traditional LESO, the design of FOLESO is more flexible and thereby the disturbance estimation error can be further reduced. Based on the proposed FOLESO, a fractional-order linear active disturbance rejection control (FOLADRC) strategy has been designed for grid-side current control of three-phase voltage-type pulse width modulation (PWM) rectifiers. In this way, the harmonic suppression property can be enhanced without sacrificing the tracking performance, and the ideal grid-side current can be achieved. Furthermore, the detailed design process, implementation mode and parameter tuning of FOLADRC are also given in this paper. The theoretical analysis and experimental results show that the proposed method is effective and superior to the traditional PI control or linear active disturbance rejection control (LADRC) strategy.

A Soft-Switching Bridgeless Buck-Boost Power Factor Correction Converter With Simple Auxiliary Circuit and Low Input Current THD

In this paper, a new bridgeless (BL) buck-boost power factor correction (PFC) converter using pulse width modulation (PWM) control is presented. The introduced structure operates in discontinuous conduction mode (DCM) to achieve the sinusoidal form of the input current inherently. The proposed converter utilizes a simple zero voltage transition (ZVT) circuit in which the auxiliary switch is turned ON and OFF under zero current switching (ZCS) condition, and the main switches turn ON and OFF under zero voltage switching (ZVS). Moreover, all diodes are turned OFF under ZCS condition, and the reverse recovery problem is solved. By reducing the number of semiconductor elements in the current flow path, conduction loss is minimized. Also, the proposed structure utilizes only one magnetic element. The above-mentioned advantages along with a low total harmonic distortion (THD) and high efficiency are the main benefits of the proposed structure compared to previous topologies. In addition, unlike the BL-buck converter, the input current dead angle is omitted without adding any extra components. Finally, a 500 W-100 kHz prototype at 90-265 Vrms input and 96 V output is implemented to verify the theoretical analysis and it illustrates the efficiency of 97.35 % and the input current THD is about 2.7 % at 220Vrms input voltage.

Active Vector Modification for Circulating Current Suppression of Paralleled Inverters Using Two-Step Sector Indexing-Based Discontinuous SVPWM

Due to the discrepancy of paralleled inverters, the zero-sequence circulating current (ZSCC) is a critical issue in a paralleled inverter fed permanent magnet synchronous machine (PMSM) drive system. The conventional solution to this issue is to adjust the duration of two zero vectors, however, will not be appropriate under the discontinuous space vector pulse-width modulation (DSVPWM) control using only one zero vector. For overcoming the above issues, an active vector modification based ZSCC suppression and a two-step sector indexing based DSVPWM are proposed in this paper. It uses both reference voltage and current vectors to jointly determine the drive signals in a two-step manner, which avoids the circulating current jump due to the coexistence of different zero vectors and can also reduce the switching loss by 50% in theory. Meanwhile, the low-frequency ZSCC can be online suppressed by a proposed real-time modification of durations of active vectors, which is finally verified together with the proposed two-step sector indexing method on a PMSM fed by two paralleled inverters.

A Systematic Review of Emergency Braking Assistant System to Avoid Accidents Using Pulse Width Modulation and Fuzzy Logic Control Integrated with Antilock Braking

The increasing number of fatalities in nations across the world because of a deficiency of protective technology in automobiles has created a chaotic scene in recent years. However, the car driver’s Perception-Reaction Time (PRT) plays an important variable during such accidents and emergencies. The Anti-Lock Braking System (ABS) seems a viable technology, which today is used to prevent tires from sliding during quick brakes, whereas EBS is designed for braking assistance during tuning or emergency braking. Physical weight, rotational rigidity, diameter, and tire material strength of the vehicle are all used to simulate them. Advance Driver Assistance Systems (ADAS), which include Anti-lock brakes (ABS) and Emergency Braking Systems (EBS), are the foremost viable technique for minimizing the environmental impact and uncertainties of driving road transportation. The presented systematic review aims to deliver a ground-level analysis that can be used to enhance the safety of motor vehicle driving, reduce wheel slip to achieve the best possible stopping distance in commercial and specialized vehicles, and influence future transportation. In this study, the most widely utilized technologies for ADAS have been reviewed and discussed. Various sensors used to improve braking and vehicle performance have been systematically studied in the context of low power-consuming techniques like pulse width modulation. An analysis of emergency braking procedures performed by riders with varying degrees of braking expertise was conducted using previously collected experimental data, and the results were used to conclude potential loss of control situations.

An NPC‐type fault‐tolerant MLI with symmetrical and asymmetrical voltage modes

SummaryCurrent studies have been challenging in reducing the number of devices and ensuring fault tolerance features of the multilevel inverters (MLIs). This article proposes a new fault‐tolerant neutral point clamped (NPC)‐type MLI using two three‐level NPC legs, which can work in symmetric and asymmetric modes to generate nine and 17‐level output voltage, respectively. The proposed converter has less device count and low total blocking voltage (TBV); further, the converter has different redundant switching states for tolerating different categories of faults. This article also implements a modified pulse width modulation (PWM) control strategy to ensure the zero‐dc offset at the output when asymmetrical voltage levels appear with the occurrence of switch faults. A detailed operation of the proposed converter under symmetric and asymmetric modes is presented for healthy and different categories of faults. The converter's feasibility is verified by its current and voltage characteristics obtained from the MATLAB‐SIMULINK software and the experimental prototype. Further, the efficiency of the converter is verified with the PLECS software. Finally, a comparison with recently proposed topologies is performed to emphasize converter performance.

Development and Implementation of LED Street Lights with Bright and Extinguishable Controls and Power Converters.

This study developed and implemented a driving power supply for light-emitting diode (LED) array streetlamps. The power stage was a quasi-resonant (QR)-flyback converter, its input power was the alternating-current power, and the LED array streetlamp was driven by the direct-current output power. The developed QR-flyback converter was operated in discontinuous conduction mode, and the pulse-width modulation (PWM) control chip was used to switch and conduct at the resonant valley of the drain-source voltage on the metal-oxide-semiconductor field-effect transistor (MOSFET) switch to reduce the switching loss. Moreover, the PWM control chip had a disable function, which was connected with a bright and extinguishable control circuit, and the high/low voltage level signal output by the Arduino development board can be used to control the output power of the QR-flyback converter, achieving bright and extinguishable controls for the LED array streetlamp.

Analysis and Control of PWM Buck-Boost AC Chopper Fed Single-Phase Capacitor Run Induction Motor

Single phase capacitor-run induction motors (IMs) are used in various applications such as home appliances and machine tools; they are affected by the sags or swells and any fault that can lead to disturb the supply and make it produce rms voltage below or above the rated motor voltage, which is 220V. A control system is designed to regulate the output voltage of the converter irrespective to the variation of the load and within a specific range of supply voltage variation. The steady-state equivalent circuit of the Buck-Boost chopper type AC voltage regulator, as well as the analysis of this circuit are presented in this paper. Switching device for the regulator is an IGBT Module. The proposed chopper uses pulse width modulation (PWM) control technique to chop the input voltage into segments in order to guarantee rated rms voltage supplied to the load, which is capacitor-run induction motor. Proportional integral (PI) controller is used to obtain very small steady state error, stable and fast dynamic response, and robustness against variations in the line voltage. The complete system is simulated using software package, and the results are obtained to verify the proposed control method.

Pulse width modulation control for stochastic Lagrange systems

The pulse width modulation (PWM) control for Lagrange systems driven by servo motors in stochastic environment is researched in this paper. Principles of PWM for stochastic nonlinear systems are proved, a continuous control bounded in probability of stochastic Lagrange system is designed, and the stochastic closed-loop nonlinear programming is modeled in the same form as that in the deterministic case. Sure boundedness of the control is required as a hard constraint, and the stochastic quadratic programming problem is presented for which an analytic solution is constructed and the expression of the optimal duty ratio is obtained. Finally, the main procedures of design and implementation of the stochastic PWM are summarized, and the effectiveness of the proposed scheme is demonstrated by a simulation of articulated manipulator.

Discontinuous PWM Strategy with Frequency Modulation for Vibration Reduction in Asynchronous Machines

The aim of this paper is to present our research into the reduction of vibrations in induction motors. The use of power inverters results in the generation of electrical harmonics, which increase the level of the mechanical vibrations of electrical machines. To reduce these harmonics, we present a discontinuous pulse-width modulation (PWM) control strategy based on carrier-wave modulation applied to multilevel inverters. Using the proposed modulation technique, the amplitude of the electrical harmonics is reduced, as compared to other conventional techniques. These current harmonics produce the MMF (magnetomotive force) harmonics in the air gap, which are one of the main sources of vibrations. The control strategy makes it possible to vary the electrical spectrum at the output of a multilevel inverter by modifying a control parameter of the carrier wave in the PWM, thus avoiding the natural frequencies of mechanical resonance. The proposed technique also has the feature of attenuating the total harmonics distortion of the voltage of the multilevel inverters, as well as the achievement of a higher RMS value of the output voltage for the same DC level. Laboratory results for an induction motor with different modulation strategies, applied in a multilevel inverter and compared to the strategy presented, are attached.

Precision Variable-rate Control System for Mini-UAV-based Pesticide Application

Mechanized and efficient pesticide application is an effective measure to prevent crop diseases, control pests, and ensure stable yield. For crops in greenhouses, due to the complex operating environment, the traditional mechanical spraying method will lead to excessive pesticide spraying and pesticide residues. Based on the ultrasonic sensor array, a small crop canopy volume calculation model is proposed, and the Pulse Width Modulation (PWM) control model of nozzle flow is established. The compensation time of opening and closing delay of the nozzle was determined to be 0.201 s by the high-speed photography method. The optimal operating speed was determined to be 0.3 m·s−1 through the benchmark test. Then, the precision variable spraying control method was integrated to develop the precision variable plant protection UAV based on an ultrasonic sensor array. The test results showed that the droplet deposition density was greater than 20 drop s·cm−2, and the droplet coverage rate of precision variable spraying was less than 30%. In the experimental area, the pesticide dosage of conventional and precision variable spraying was 0.24 L and 0.15 L, respectively, The precision variable-rate spraying saved pesticide usage by 34.5%. The system can realize precise variable spraying according to crop location and crop canopy volume changes. This study will promote the rapid development and application of precision spraying technology for small plant protection UAVs.

Performance Analysis of Three Phase Induction Motor With Variable Frequency Drives Using Pulse Generator Pwm and Svpwm

Three-phase induction motor is an alternating current motor that is most widely used in industry or offices. In principle, the induction motor is operated at a constant speed, if the induction motor is given a load that is not balanced with its constant speed, the speed of the induction motor will change. For this reason, one of the common methods used to adjust the rotational speed of an induction motor as desired is to use a Variable Frequency Drive (VFD). The VFD can be controlled by pulse generator PWM (pulse width modulation) and SVPWM (space-vector pulse width modulation) which are part of the value of the frequency and modulation index. In this final project, what is investigated and compared for more optimal results is the PWM and SVPWM output values with the variables of Rotor Speed, Slip, Fslip, Stator Current, and THD (Total Harmonic Distortion). In this thesis, a comparison of simulation with MATLAB between PWM and SVPWM is carried out using design and experimental methods. The final result obtained is for Rotor Speed, SVPWM control is more optimal with an average percentage of 2.2%. For more optimal SVPWM control slip reaches 1.53%. for Fslip control SVPWM is more optimal reaching 0.76%, SVPWM control produces a smaller current consumption at a frequency of 50 - 40 Hz. for THD Current, PWM control is more optimal with a percentage of 1.07%

New backstepping controllers with enhanced stability for neutral point clamped converters interfacing photovoltaics and AC microgrids

This work presents a new approach to obtain pulse width modulation (PWM) backstepping controllers with enhanced stability for neutral point clamped (NPC) multilevel converters to deliver energy from photovoltaic (PV) panels into AC microgrids. Stability enhanced backstepping non-linear controllers are obtained from the equations of the dq frame converter model to regulate the PV voltage to track the power point, and to balance the capacitor voltages through DC biasing of the PWM carriers, using a novel dynamic equation of the capacitors incremental unbalance voltage, while controlling the grid injected AC currents. Besides, the proposed controllers can change the PV panels operating point to curtail inject power for AC voltage / frequency regulation. The NPC converter and AC microgrid are simulated in MATLAB / Simulink and implemented in the laboratory to evaluate the performance of the PV energy conversion using the new stability enhanced backstepping PWM control. Simulation and experimental results show that, regarding predictive controllers, the novel stability enhanced backstepping requires lower microprocessor power than predictive controllers while presenting a similar behavior in PV voltage and power point tracking regulation, or for voltage / frequency regulation of the microgrid. AC injected currents show low levels of total harmonic distortion similar to predictive controllers and can operate at near unity power factor.

Hybrid Switching Control-Based DC to AC Inverter for Microgrid Using Renewable Energy Sources

Hybrid switching control-based direct current (DC) to alternating current (AC) inverter is a method of controlling the flow of power from DC sources such as solar panels or wind turbines to AC loads in a microgrid. In a microgrid, renewable energy sources are often used to supplement traditional sources of energy and improve overall energy efficiency. To simulate micro-grid systems, an effective three-legged IGBT inverter has been developed using Matlab R2016a/Simulink. The inverter switches are controlled by a pulse controller, which creates the switching gate pulses. This work models the output voltage and current waveforms of the three-phase 180° voltage source inverter that supplies nonlinear loads. To lower the total harmonic distortion (THD) of the current and voltage outputs of the three-phase voltage source converter (VSC), a filter circuit and a two-level pulse width modulation (PWM) generator have been presented. This pulse-width modulation generator compares the modulating signal and a high-frequency triangular carrier wave. Sinusoidal pulse width modulation (SPWM) is used for PWM control. Moreover, the hybrid switching control-based DC-to-AC inverter utilizes a combination of pulse width modulation (PWM) and hysteresis current control techniques to maintain a constant AC output voltage and frequency. PWM control is used to regulate the voltage, while hysteresis current control is used to regulate the current. Additionally, an inductor-capacitor-inductor (LCL) filter is used to improve the stability of the power converter by providing a damping effect on the system. Overall, the LCL filter is a versatile and effective tool for improving the performance of power inverters, especially in applications where high efficiency and low harmonic distortion are important. IUBAT Review—A Multidisciplinary Academic Journal, 6 (1): 25-46

Modeling and Performance Analysis of a Grid-Connected Photovoltaic System with Advanced Controller considering Varying Environmental Conditions

This paper presents a mathematical model of 255 kW grid-connected solar photovoltaic (SPV) system. To study the performance characteristics of the grid-connected SPV system, a new hybrid adaptive grasshopper optimization algorithm with the recurrent neural network (AGO-RNN) control technique was implemented. Furthermore, the power quality at the point of common coupling (PCC) has been studied using the conventional (PSO) and proposed AGO-RNN controllers. The characteristics of the PV system were analyzed under varying environmental (variable irradiance and temperature) conditions considering 3 different cases such as (i) standard test conditions (STC), (ii) variable radiation with constant temperature, and (iii) variable radiation with variable temperature. For each case, the total harmonic distortion (THD) has been calculated using the proposed AGO-RNN control technique, and the results were compared with particle swarm optimization (PSO) technique. The 255 kW PV model is initially developed and connected to a three-level NPC inverter, an MPPT-based perturbation and observation algorithm. Later, the PV model is controlled by an AGO-RNN pulse width modulation (PWM) controller and is then integrated to the main grid at PCC. The main advantage of this technique is exploiting the separate DC-DC converter between the SPV module and the inverter. Finally, the proposed grid-connected SPV system was simulated on MATLAB for analyzing the performance of the system based on its I-V and P-V characteristics, inverter voltage, grid power, gird voltage, grid current, power factor, and THD under different environmental conditions. The simulation results demonstrate that the current magnitude and THD of the SPVGC system are improved with the cutting-edge AGO-RNN controller compared to PSO in all three different scenarios, and this value is less than 1.6%, which is within the permitted limits of IEC 61727 standards.

A single-phase direct buck-boost AC–AC converter with minimum number of components

In this paper, a single-phase direct pulse width modulation (PWM) buck-boost AC–AC converter is proposed. The proposed converter utilizes a minimum number of semiconductor switches and passive components that decreases the converter power losses and offers high efficiency. It can be operated with simple PWM control and doesn’t require soft-commutation strategies. It does not suffer from input source shoot-through and commutation problems. Moreover, it supplies both continuous input and output currents. The common sharing ground of the input and output gives the proposed converter the feature that it can be utilized for voltage sag and swell compensation. A comparison of the proposed converter performance with similar existing converters is presented. Also, detailed circuit analysis, component design guidelines, and simulation results using the MATLAB/Simulink environment are demonstrated. A laboratory prototype has been built and tested to validate the converter performance and confirm the results obtained by computer simulation.

Experimental Investigation of Decoupled Discontinuous PWM Strategies in Open-End Winding Induction Motor Supplied by a Common DC-Link

Currently open-end winding induction motors fed by a dual inverter (OEWIM-DI) present an innovative approach to enhance the performance of modern electric drive systems; such as electrical vehicles and electric aircraft applications. However, the dual inverter topology requires a proper switching control strategy to enable the OEWIM drive to fully achieve its performance. This work aims to investigate experimentally the impact of different Decoupled Discontinuous Pulse Width Modulation (DDPWM) control strategies on the performance of the OEWIM-DI supplied by a common DC-link. The criteria performance adopted in this study are: (i) the Total Harmonic Distortion (THD) of the current and voltage, (ii) the Zero Sequence Voltage (ZSV), (iii) the Common Mode Voltage (CMV), and (iv) the dual inverters losses. The various DDPWM control schemes for the 1.5 kW OEWIM-DI motor drive are implemented on a dSPACE 1104 board and the results are compared with the popular and widely used Space-Vector PWM (SVPWM) strategy. From the results, it can be concluded that the optimised DDPWM technique gives the best performance. This technique has reduced the CMV by one level and reduce the losses by 50% while having the same THD and ZSV obtained with the SVPWM technique.

Averaged Behavior Model of Current-Mode Buck Converters for Transient Power Noise Analysis

Accurate evaluation and simulation of power noise is critical in the development of modern electronic devices. However, the widely used target impedance fails to predict the low-frequency noise generated in a device due to the existence of the dc–dc converter, whose output impedance can change under different loading conditions. A physical circuit model is then desired to replicate the behavior of a voltage regulator module, and the average technique is an efficient method to estimate the noise of a pulsewidth-modulated (PWM) converter. With the emergence of converters with adaptive on-time (AOT) controllers, more complex averaging methods are required, but none of them supports transient simulation. A general, efficient, and accurate modeling technique is presented in this article, whose framework supports both current-mode PWM and AOT controllers. In addition, a novel two-step parameter extraction method is proposed, which can be used to evaluate the equivalent values of internal feedback parameters of an encrypted simulation model or from measurement. The modeling method is validated by both simulation and measurement.

A Variable Switching Frequency Space Vector Pulse Width Modulation Control Strategy of Induction Motor Drive System With Torque Ripple Prediction

The constant switching frequency space vector pulse width modulation (CSFSVPWM) generates high-frequency harmonics with integer multiples of the switching frequency, making it fail to fully exploit the potential of pulse width modulation (PWM) technique. In this paper, a variable switching frequency space vector pulse width modulation technique with the function of torque ripple prediction is proposed for induction motor drive system, which could optimize the high-frequency harmonic current distribution and torque ripple. The mathematical correlation between inverter average voltage and instantaneous voltage under the space vector pulse width modulation (SVPWM) is first analyzed, followed by the analysis of current ripple in a switching cycle using the typical seven-segment SVPWM, thus the torque ripple of induction motor during this period can be predicted. The switching period is dynamically adjusted according to the magnitude of predicted torque ripple, and the average switching frequency is maintained to be the same with that of CSFSVPWM. The effectiveness of the proposed method in suppressing high-frequency current harmonics and torque ripple is fully verified by experimenting on a 2.2 kW induction motor drive system, and a comprehensive comparison with CSFSVPWM and random PWM modulation is implemented.