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The six-phase two-level voltage source inverter (SPTLVSI) fed the six-phase asymmetrical induction motor (SPAIM), which has a stator that splits the three-phase windings into two groups those are shifted electrically by 30 ∘ . It introduces significant current harmonics of the order of 6 k ± 1 k = 1 , 3 , 5 ... , which can be mapped into the non-flux/torque producing X - Y sub-plane. These harmonics cause only losses in the motor winding as they do not take part in torque production. The authors propose a new space vector modulation technique named the 48-sector vector space decomposition-based space vector pulse-width modulation (C6 ϕ SVPWM48) technique, which has been verified using MATLAB (Matrix Laboratory) simulation and reported by the authors in the previous work, and the work is extended in this paper. This paper presents a contribution to compare the proposed technique with the 12-sector vector space decomposition-based space vector pulse-width modulation (C6 ϕ SVPWM12) based on CMV (Common mode voltage) , switching loss of the inverter, torque ripple, and stator current distortion. The C6 ϕ SVPWM48 technique has been implemented experimentally on the SPTLVSI fed a prototype of 200 V, 2 kW SPAIM. The C6 ϕ SVPWM48 technique is controlled using the ARM cortex M4 32-bit microcontroller (STM32F407VGT6) and the SPTLVSI during steady-state and dynamic operating conditions. The experimental results of the C6 ϕ SVPWM48 technique are discussed and presented. Furthermore, it reduces the harmonic current drawn by the machine to a large extent, consequently, the copper losses of the machine and also reducing the average switching loss. [ABSTRACT FROM AUTHOR]

This paper deals with the design, implementation, and measurements of a frequency converter with bipolar sinusoidal pulse width modulation (SPWM) of output voltage for two-phase induction motors. The paper is dedicated to an analysis of the operation of a two-phase frequency converter and its implementation. The inverter has a single-phase H-bridge topology with split DC link and bipolar switching to minimise the number of components. Insulated gate bipolar transistors (IGBTs) are used in the realisation of the inverter power section. The inverter is controlled using a digital signal processor (DSP) TMS320F28335. Measurements with a 0.12 kW two-phase induction motor were performed to verify the correct operation of the inverter. The influence of the switching frequency on the motor current ripple is measured for frequencies of the first harmonic up to 100 Hz. [ABSTRACT FROM AUTHOR]

The paper presents a comprehensive study on modeling a doubly fed induction generator (DFIG) and explores various control strategies for pulse-width modulation (PWM) in back-to-back (B2B) converter techniques. A DFIG is characterized by a wound rotor and three slip-ring induction machines, with the stator winding directly connected to the power grid and the wound rotor interfaced with the grid through a 3-phase AC/DC/AC converter. Typically, the converter connected to the grid is referred to as the grid side converter (GSC), while the converter attached to the rotor's slip-ring circuit is termed the rotor side converter (RSC). This research delineates various PWM-based B2B converter methodologies applied to the DFIG within wind energy turbines, aiming to regulate the RSC for optimal power capture. The study employs MATLAB/SIMULINK for constructing a multi-phase voltage source converter two-level (VSC-2L) model, leveraging different PWM techniques including Sine-PWM, Sinusoidal-PWM with third harmonic injection (THIPWM), and space vector PWM (SVPWM). These techniques are assessed based on total harmonic distortion (THD) using fast Fourier transform (FFT) analysis. The findings indicate that SVPWM offers several advantages, such as ease of digital implementation, lower THD, reduced switching frequency losses, and more efficient utilization of the DC link voltage, thereby enhancing control strategy effectiveness. [ABSTRACT FROM AUTHOR]

Parabolic carrier Pulse Width Modulation (PWM) method is considered as one of the direct current control methods for the Voltage Source Converters (VSCs). This method has an excellent dynamic response. Besides, it offers a constant switching frequency by employing a pair of parabolic PWM carriers. However, it suffers from some drawbacks and limitations. The major drawback of this method is its sensitivity to the inductance variations. In other words, in grid-connected applications, the exact value of grid inductance should be known to achieve a proper performance. Moreover, it is essential that during each switching cycle, the voltage at the point of common coupling remains constant. In grid connected applications such as active power filter, these drawbacks may lead to operation at variable or non-expected frequencies. Therefore, this paper provides suggestions to deal with the situation. In this paper, by applying the conventional method, the aforementioned problems are examined in a grid-connected active power filter. It is shown analytically that by using the proposed method, the problem of sensitivity to inductance is overcome and the necessity for a constant voltage at the point of common coupling in a switching period will be solved as well. The simulation and experimental results are presented. [ABSTRACT FROM AUTHOR]

In this paper, we present a new digital resonant current controller that can be applied in single-phase and three-phase alternating current (AC) power converters, based on voltage source inverters (VSI) with pulse width modulation (PWM). Since power converters based on PWM introduce fractional time delays regarding the sampling period (T s), because of the current sampling and PWM command updating techniques that are employed, there is a need to develop analytical tools for precise modelling of these types of delays. To achieve this, the advanced Z-transform is applied in order to model the AC controllers in VSIs with PWM for the general case of a fractional time delay, including power converters with current sampling within a PWM period at any chosen time instance. This new approach to power converter modelling and current sampling allowed us to develop a modified resonant AC current controller for a VSI with RL load, based on the pole-placement parameter tuning method. It includes fractional time delays, which are conventionally employed in the power converter design, in the controller parameter derivations, and introduces the minimal order resonant controller that enables strict placement of all closed-loop control system poles. Simulations and experimental tests are carried out to show the improvements introduced by novel solution in this paper compared with conventional resonant current controllers. In the analysis of dynamic performance and robustness, in this paper conventional indices are applied to compare the proposed controller with a conventional design. • The introduction of the Advanced Z-Transform enables analytical modelling of the plant that includes a fractional time delay. • Novel pole-placement based parameter tuning procedure is presented, which places all closed-loop system poles at required positions. • New controller is compared with existing solution by test runs and conventional dynamic performance and robustness indices. [ABSTRACT FROM AUTHOR]

In this paper, we present a new digital resonant current controller that can be applied in single-phase and three-phase alternating current (AC) power converters, based on voltage source inverters (VSI) with pulse width modulation (PWM). Since power converters based on PWM introduce fractional time delays regarding the sampling period (T s), because of the current sampling and PWM command updating techniques that are employed, there is a need to develop analytical tools for precise modelling of these types of delays. To achieve this, the advanced Z-transform is applied in order to model the AC controllers in VSIs with PWM for the general case of a fractional time delay, including power converters with current sampling within a PWM period at any chosen time instance. This new approach to power converter modelling and current sampling allowed us to develop a modified resonant AC current controller for a VSI with RL load, based on the pole-placement parameter tuning method. It includes fractional time delays, which are conventionally employed in the power converter design, in the controller parameter derivations, and introduces the minimal order resonant controller that enables strict placement of all closed-loop control system poles. Simulations and experimental tests are carried out to show the improvements introduced by novel solution in this paper compared with conventional resonant current controllers. In the analysis of dynamic performance and robustness, in this paper conventional indices are applied to compare the proposed controller with a conventional design. • The introduction of the Advanced Z-Transform enables analytical modelling of the plant that includes a fractional time delay. • Novel pole-placement based parameter tuning procedure is presented, which places all closed-loop system poles at required positions. • New controller is compared with existing solution by test runs and conventional dynamic performance and robustness indices. [ABSTRACT FROM AUTHOR]

Recently, the three-phase induction motor (IM) has been widely used in AC motor drives and in industrial applications. The IM suffers from the accuracy of controlling the speed when it operates at different loads; this problem attracts the attention of many researchers in this field. This paper presents an Intelligent Hybrid Control System using ANFIS (Adaptive Neuro-Fuzzy Inference System)-Optimization for Scalar Control (SC) of an Induction Motor. In order to obtain optimum performance of the motor and to decrease the Total Harmonics Distortion (THD) of the motor current a Voltage Source Inverter (VSI) based on the Pulse Width Modulation technique (PWM) is used to drive the motor. To improve the speed response, accuracy and the motor's performance, an improved hybrid control system involves an optimization control method in addition to an Adaptive Neuro-Fuzzy Inference System used to adjust the amplitude and the Modulation Index (MI) of the reference signal. The proposed hybrid system improves the transient stability of motor speed and reaches a steady state much faster than the traditional controller. The Matlab-Simulink results proved the remarkable effectiveness of the proposed controller when comparing the results with two other controllers, the usual PI controller and the optimization controller. [ABSTRACT FROM AUTHOR]

The high-gain DC converter is a crucial step in the conversion process for raising the voltage from PV panels to the desired voltage level in renewable energy applications. This article proposes a three-phase grid connected PV system with a novel interleaved high gain DC converter fed 3-level Neutral-Point-Clamped (NPC) Inverter. The novel high-gain DC converter consists of an interleaved boost converter (IBC) at its input side, a switched capacitor cell, a passive clamp circuit, and a voltage multiplier unit (VMU). The interleaved arrangement eliminates the input current ripple, and the VMU is utilized to improve the overall voltage gain besides the reverse recovery problem of diodes. The proposed converter is operated at a duty cycle D = 0.6 and a high voltage conversion ratio of 17.5 which is ideal for sustainable energy applications. This paper uses the proposed converter for a grid-connected solar PV system with an NPC inverter controlled using Space Vector Pulse Width Modulation (SVPWM) technique. The SVPWM strategic approach is a prevalent modulation technique for NPC inverter due to its extensibility in choosing the ideal voltage vectors. It uses an active filter, which is more dependable, dynamically better behaved, and capable of operating accurately under distorted grid voltages under varying load conditions. The proposed grid-associated PV system with a novel interleaved converter and 3-level NPC inverter is employed in Matlab/SimPower System and experimentally verified. Power loss and efficiency calculations were performed on the DC converter side, and the efficiency was 96.07%. NPC inverters have a THD of 22.2%. Results from simulations and experiments indicate that the suggested topology can efficiently extricate the maximal amount of power from PV modules and inject energy into the grid system with excellent steady-state and dynamic performance. [Display omitted] • The Incremental & Conductance MPPT method is engaged for tracking MPP. • The grid connected novel DC converter has the high voltage gain of about 17.5 at a nominal duty ratio of D = 0.6. • The novel DC converter is appropriately utilized for 3-level NPC Inverter to generate grid voltage. • The proposed structure is successfully synchronized to the grid by Synchronous Reference Frame Phase Locked Loop (SRFPLL). [ABSTRACT FROM AUTHOR]

The modular multilevel converter (MMC) has proved to be a suitable converter topology for high-voltage direct current systems (HVDC). Some efforts can be identified in the literature to apply the MMC in static synchronous compensators (STATCOMs). However, the MMC has some challenges in the modulation schemes and energy storage requirements. Indeed, the literature has not presented a clear analysis of the modulation strategy impact on energy storage requirements. Thus, this paper introduces the spreading factor index to compare different modulation strategies in terms of capacitor voltage balancing capability. In addition, the impact of energy storage requirement on different modulation strategies is presented. In order to demonstrate the methodology, two strategies were selected: phase-shifted pulse-width modulation (PS-PWM) and nearest-level control with cell tolerance band algorithm (NLC-CTB). Subsequently, the MMC performance for each modulation strategy was compared in terms of energy storage requirements, capacitor voltage balancing capability, losses and current distortion. Besides, different operation conditions were analyzed in a case study based on a 15 MVA STATCOM. The results indicate that PS-PWM reduces the energy storage requirements, while the NLC-CTB modulation reduces the converter power losses. [ABSTRACT FROM AUTHOR]

Multilevel inverters are a novel type of dc-ac converter designed for medium and high voltage and power applications. Cascaded multilevel inverters are the most common inverters used in renewable energy applications. Despite the numerous advantages, the presence of extra circuit components in the design causes reliability concerns with these inverters. Researchers have faced a significant difficulty in constructing inverters with improved dependability by lowering total harmonic distortion (THD). This paper proposes a concept of Grid connected PV system with multilevel inverter topology. The PV system is implemented by using mathematical analysis and MPPT based dc-dc boost converter is used to improve the performance of PV system. In this paper, perturb and observe MPPT technique is implemented. For obtaining better harmonic distortions and proper synchronization with grid a multi-level inverter is implemented. This paper proposes a novel multilevel inverter topology for renewable energy operations which produces 31 and 51 level output voltages. The conventional topology is formed with 10 IGBT switches. A closed loop controller with sinusoidal pulse width modulation technique is implemented to generate gate signals required for 31-Level converter. The 51-Level converter is modelled with 8-IGBT switches and 4-diodes, also space vector and sinusoidal pulse width modulation techniques are used to generate the gate signals for switches. This proposed system is tested and verified in MATLAB and a comparative analysis made between sinusoidal and space vector modulation in 51-Level topology. [ABSTRACT FROM AUTHOR]

A newly designed DC–AC three phase bidirectional converter (DATBC) with an encapsulated DC–DC converter (EDC) for the energy storage system (ESD) is analysed and investigated in this research paper. By using encapsulated or embedded or hidden DC–DC converter a stable and constant DC bus is developed between the encapsulated DC–DC converter and DC–AC three phase bidirectional converter. The proposed converter is entirely different from the traditional dual-stage DC–AC converter, because it takes less than 20% of power used for the DC–AC conversion process. So, this reduced power consumption increases efficiency to a considerable value. A new control technique for zero sequence has been adopted components are inserted in the modulating signal based on carrier pulse width modulation (CPWM). Working principle, implementation and characteristics of the DC–AC three phase bidirectional converter are analysed. Effectiveness and feasibility of the developed converter are examined with a proto-type model. [ABSTRACT FROM AUTHOR]

This paper presents the design of a grid-connected hybrid system using modified Z source converter, bidirectional converter and battery storage system. The input sources for the proposed system are fed from solar and wind power systems. A modified high gain switched Z source converter is designed for supplying constant DC power to the DC-link of the inverter. A hybrid deep learning (HDL) algorithm (CNN-BiLSTM) is proposed for predicting the output power from the hybrid systems. The HDL method and the PI controller generate pulses to the proposed system. A closed loop control framework is implemented for the proposed grid integrated hybrid system. A 1.5 Kw hybrid system is designed in MATLAB/SIMULINK software and the results are validated. A prototype of the proposed system is developed in the laboratory and experimental results are obtained from it. From the simulation and experimental results, it is observed that the ANN controller with SVPWM (Space vector Pulse width Modulation) gives a THD (Total harmonic distortion) of 2.2% which is within the IEEE 519 standard. Therefore, from the results, it is identified that the ANN-SVPWM method injects less harmonic currents into the grid than the other two controllers. [ABSTRACT FROM AUTHOR]

Traditional plant protection machinery cannot apply pesticides according to the actual growth demand of crops, which causes a lot of pesticide waste and serious environmental pollution. Based on this, an intelligent variable-rate application system based on 3D LiDAR (light detection and ranging) scanning and PWM (pulse-width modulation) control for maize canopy was developed in this paper. After completing the performance testing, the system was mounted on a lightweight high-clearance self-propelled sprayer by remote controlling with an operating width of 6.0 m, and a ground gap of 2.0 m. And the actual operational performance of the sprayer showed that the prediction error of LiDAR for plant height was within 10%, which illustrated the accuracy of the detection system and the reliability of the variable application based on the plant height change. And the variable-rate system could adjust the spray volume in real-time according to the plant height change. The penetration rate of the upper, middle, and bottom layers maintained a relatively stable state (upper > middle > bottom) at variable-rate application and could reach the normal application level. This study can provide new ideas for efficient pests and diseases control of high stalk crops, especially suitable for small fields, and gives a reference for the structural design of new precise variable-rate application machinery and performance optimization of efficient application technology. • A complete intelligent application system has been developed. • A reliable decision model of application quantity is established. • The intelligentsprayer meets the spraying technology requirements. [ABSTRACT FROM AUTHOR]

Staircase Modulation (SCM) is a popular switching strategy for multilevel inverters (MLI), which is often a preferable alternative to Pulse Width Modulation (PWM) due to its reduced switching losses, especially for MLIs with a relatively high number of voltage levels (N). In some applications, such as motor drives, or when output filters are applicable, SCM may also suit MLIs with moderate N values. While MLIs with Equal DC Sources (EDCS) are more common, MLIs with Unequal DC Sources (UDCS), such as asymmetric Cascaded H-Bridge (CHB) MLIs are known to further reduce the waveforms' Total Harmonic Distortion (THD). The main objective of SCM is to adjust the waveform's fundamental component, while employing some harmonic mitigation strategy, such as THD minimization. Such an optimization approach relies on an accurate THD formulation, which eliminates underestimation errors associated with numerical THD approximations. This paper reveals novel generic analytical formulations of both Phase-voltage THD (PTHD) for single-phase MLIs and Line-voltage THD (LTHD) for three-phase MLIs. The revealed exact formulation approach is derived from Fourier series representation of THD, resulting in simple closed-form PTHD and LTHD expressions, applicable to any MLI topology, with either EDCS or UDCS configurations, and arbitrary value of N (odd and even). Given an arbitrary N value, the proposed formulations can be used to generate symbolic N -level PTHD or LTHD expressions, which are symbolic functions of the Phase Switching Angles (PSA) and (optionally) the DC source Ratios (DCR). The revealed THD formulations are verified and compared against recently introduced time-domain-based THD formulations. It is shown that when both time and frequency-based formulations are employed in THD minimizations to form a novel Hybrid Temporal-Spectral (HTS) Optimal Minimization of THD (OMTHD) approach, even better results can be achieved. The novel OMTHD is deeply explored and verified by both digital simulations and Controller + Hardware in Loop (C-HIL) based real-time experiments using 7- and 8-level three-phase MLI configurations. A downloadable supplemental file containing Maple and MATLAB functions of the proposed THD expressions, as well as pre-calculated sets of optimum variables for different values of N is provided for readers' convenience. [ABSTRACT FROM AUTHOR]

This paper presents an efficient supply current wave shaping technique for bridgeless interleaved Single Ended Primary Inductor Converter (SEPIC). The SEPIC converter converts an Alternating Current (AC) to Direct Current (DC) with the boost converter. Power Factor Correction (PFC) is progressively significant to achieve high energy efficiency. The overall system efficiency can be increased as the bridgeless topology has less conduction losses from rectifying bridges. Also, the bridgeless and interleaved techniques are incorporated in this study to achieve better performance. The performance of the system is analyzed on both current control and sensor-less techniques. Different controllers such as Proportional Integral (PI) control, peak current control, Non-Linear Carrier (NLC) control, and sensor-less current control are integrated. All the above controllers are implemented using MATrix LABoratory (MATLAB)/SIMULINK. The performance parameter, namely Power Factor (PF), Total Harmonic Distortion (THD), is computed for both open loop and closed loop condition. The sensor-less current control method is implemented using the DsPIC30F2010 controller. The circuit performance is also verified from the simulation and hardware results. The proposed controller has inbuilt Analog-to-Digital Converter (ADC), Digital-to-Analog Converter (DAC), Pulse Width Modulation (PWM) generator, and provides fast responses. [ABSTRACT FROM AUTHOR]

Control of multi-phase machine in both healthy and post-fault operations has recently gained considerable interest. Finite control set model predictive control (FCS-MPC), in particular, has been proposed to drive multi-phase machines to avoid sophisticated pulse width modulation (PWM) methods. Nevertheless, FCS-MPC generally experiences some technical limitations. One of the widely reported challenges related to FCS-MPC is the weighting factor (WF) design, which is empirically designed and found to be an operating point dependent factor. Thus, assuming a constant WF can result in poor performance. In this paper, the prediction stage of FCS-MPC for asymmetrical six-phase (A6P) induction motor (IM) has been reformulated based on double dq (2dq) modeling approach. Unlike the reported vector space decomposing (VSD)-based FCS-MPC algorithms, the proposed approach results in four control variables (the stator sequence currents i s α 1 , i s β 1 , i s α 2 , and i s β 2 ) which have the same priority. Thus, equal weighting factors could be used in the cost function, which will inherently minimize the effect of the circulating x-y current components. Performance comparison of the proposed method against VSD-based FCS-MPC is investigated. The theoretical findings are experimentally validated using a 1 kW prototype six-phase IM. [ABSTRACT FROM AUTHOR]

This paper presents a high performance squirrel-cage asynchronous motor (ASM) drive, proposed for high-speed electric vehicle (EV) propulsion. This is an indirect space vector control (IDSVC) scheme in the rotor flux frame of reference, in which the modeling is based on synchronously rotating coordinate system transformation. Space vector pulse width modulation (SVPWM) inverter fetches the controlled stator direct and quadrature axis responses from the speed and current controllers and supply necessary voltages to stator of ASM. The output voltage waveforms of SVPWM inverter are not sinusoidal in nature, which allows undesired harmonics at high frequency of operation. This due to inconsistent switching frequency. A second-order low-pass (SOLP) RLC filter with Butterworth approximation and was designed and connected in series with SVPWM inverter to grab harmonic free speed and torque profile during high speed operations. Similarly, another SOLP with a quality factor equal to 2 is designed and speed profiles of both filters are compared. The system is developed and simulated in MATLAB/SIMULINK to observe the speed and torque tracking capabilities. Simulation results show that the performance of drive under steady and dynamic states were good with Butterworth filter approximation with robust IDSVC scheme adopted over wide range speed-drive curve. [ABSTRACT FROM AUTHOR]

With the volatile oil prices and the need to reduce the emission of greenhouse gases, renewable energy resources are a very attractive alternative. Africa has a good potential for micro hydroelectric power generation. However, only a small proportion of this potential has been harnessed. As a result, most rural areas in Africa have limited access to electric power. Unfortunately, those rural communities privileged to be connected to the grid also have unreliable and expensive grid power. To meet their energy needs, some of the communities have installed and operate Pico or Micro Hydro Power Plants (MHPPs) based on the Build-Own-Operate (BOO) model. In any power generation plant, a speed governor is required for regulating the frequency of supply under varying load conditions. However, this is the single most expensive component in a MHPP and most of the community owned plants can hardly afford it and thus, have no means of continuously regulating frequency. An Electronic Load Controller (ELC) is a device used to control the sharing of constant generator output power between the consumer and dummy loads and hence, maintain the frequency of a MHPP constant. This replaces the expensive and complex speed governor. In this paper, the design and implementation of an ELC is presented. Magnetostrictive Amorphous Wire (MAW) is used as a frequency sensor. An amplifier and a signal conditioning circuit were designed to convert the analog signal from the MAW to a digital signal that is fed to microcontroller. In addition, optimal Proportional-Integral (PI) gains are determined to serve as reference gains to the microcontroller so as to generate a Pulse Width Modulation (PWM) signal to control the firing angle of the switching circuit of the ELC. The laboratory experimental test results obtained clearly show the effectiveness of the ELC to dump excess power to the damper load when the consumer load changes, and maintain the supply frequency between 49.5 and 50.5 Hz. Also, from the results, it was observed that the MAW sensor was able to measure the frequency effectively with high accuracy when compared to the frequency measurement from the tachometer. This is a key finding of the suitability of MAW sensor application in ELC for MHPPs. The designed controller is cheaper and yet able to control the frequency very effectively when compared to other ELCs and speed governors that are currently on the market. • The measured frequency using the MAW sensor compares well with that obtained using a digital tachometer: This is a key finding or novelty in this paper since the application of MAW sensor for frequency measurement in ELCs for MHPPs has not been reported in literature. • The designed ELC is effective to dump excess power to the damper load when the consumer load is less than the generator capacity. • The stabilising time for the designed ELC (obtained by using a timer) is 1.5 seconds. • The designed ELC is cheaper when compared to other ELCs and speed governors that are currently on the market. [ABSTRACT FROM AUTHOR]

This paper presents an improved stator voltage magnitude and frequency control for standalone doubly fed induction generators (DFIGs) based wind power generation systems (WPGSs). The proposed technique uses a simple finite-state predictive current control (FS-PCC). In this control method, the switching vector for the IGBT is selected to minimize the error between the reference value and the predicted value of the rotor current. Moreover, the discrete-time models of (DFIG) are needed to predict the future value of the rotor current for all possible voltage vectors generated by the rotor-side converter (RSC). Since the classic control methods in the literature use inner control loops and are based on pulse width modulation (PWM), this method does not require complex modulation stages and omits the current control loops, which reduces the control requirements. The main objective in a standalone DFIG system is to keep the stator voltage has constant in amplitude and frequency and equal to the reference value, regardless of the changes in rotor speed or load. The proposed control strategy was implemented through a 3 kW DFIG prototype platform-based dSPACE 1104 card. The simulation and experimental results show that the proposed FS-PCC offers excellent reference tracking with less total harmonic distortion (THD) in stator voltages and rotor currents. [ABSTRACT FROM AUTHOR]

This paper proposes a new optimized control of photovoltaic two stages conversion cascade composed by Three Levels Boost (TLB) and Three Levels Neutral Point Clamped (TLNPC) inverter. In order to extract the maximum power from photovoltaic generator and get a balanced DC bus voltage, the duty cycles of the two TLB switches are determinate from a Fuzzy Logic Controller (FLC) for the first switch and by adding to the first duty cycle an additional duty cycle obtained by integration of the error between the two capacitors voltages of DC bus. Balancing the bus voltages by the TLB using a single regulator avoid us to use a complex balancing algorithm by the redundant vectors of TLNPC inverter. For the control of the inverter, we used a Proportional Integral (PI) regulator optimized by PSO. This command allows us to have on one side a constant DC bus voltage and a current injection in phase with the grid voltage. To have an efficient follow-up of the TLNPC inverter reference voltages, the Space Vector Pulse Width Modulation (SVPWM) is applied. The simulation is carried out in MATLAB/SIMULINK platform. The results obtained from the application of the FLC command associated with PI PSO are better compared to the simulation without optimization in terms of sum of the absolute values of the errors at the inputs of the three PI regulators. [ABSTRACT FROM AUTHOR]

FACTS devices installation is required to guarantee high energy quality and power system stability. The present paper tackles the problem of voltage control, reactive power and power factor improvement in an electric power network by one of the AC transmission devices (FACTS) of the static synchronous parallel compensator type (STATCOM), using serial multicellular converters with different levels (three to six levels). Such converters with special attention paid to the active balancing of capacitor voltages in order to generate good quality waveforms and improve the harmonic content of the output voltage. The controller's ability and functionality are evidenced through a detailed theoretical analysis. We elaborate the compensator's operating model by stating its equivalent electrical diagram representation. This is followed by a mathematical modeling and a control model based on phase shifted pulse width modulation (PS-PWM) technique to monitor reactive power flow inside the system and maintain the voltage at the common connection point (PCC) at a steady value. The proposed system simulation is carried out using Matlab Simulink environment. Finally, a presentation and a discussion of the obtained results are provided. [ABSTRACT FROM AUTHOR]

This paper introduces a new HT-type module for both symmetrical and asymmetrical multilevel inverters (MLIs) with reduced power electric components. The proposed module comprises of two back to back T-type inverters connected with four cross-connected switches. This MLI addresses two major drawbacks associated with the conventional and other recently proposed MLIs which are the high voltage stress of switches and higher power component counts. The structure of the proposed device is designed combining the beneficial features of both T-type inverter and cross-switched inverter. The 1st feature allows the module to produce negative voltage levels deprived of any extra H-bridge circuit and thus decreasing the overall voltage stress significantly. The latter feature allows the device to utilize reduced number of switches to produce higher voltage levels. A comprehensive comparative analysis is additionally established between other MLI topologies to confirm the superiority of the HT-type MLI. From this analysis, it is found that the proposed MLI has successfully overcome the issues associated with other MLIs, it was able to produce the results following industrial standards and it outperformed other MLIs in different aspects such as power components count, cost, efficiency and dynamic performance. Selective harmonic elimination pulse width modulation (SHE-PWM) and nearest level control (NLC) algorithm is considered in this manuscript to generate the output results from the proposed HT-type module. All the details about the operating principle and modulation techniques utilized for the proposed MLI module are stated and validated by both simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a double source double diode double switch (DSDDDS) multilevel inverter to generate positive voltage and a connecting polarity changing circuit of an H-bridge inverter to generate negative voltage. By connecting the jth number of basic units in series, the desired level is obtained. Various algorithms, such as Natural, Binary, Trinary, and Quasi-Linear sequences, and two proposed algorithms are discussed to determine the magnitude of DC voltage sources in order to generate more stepped levels with fewer switches. The proposed multilevel inverter eliminates the need to turn on additional power switches for different levels, which is the main advantages of this topology. The proposed multilevel inverter is compared to conventional switched diode multilevel inverters in terms of switch count, number of ON state switches per level, driver circuits, and total standing voltage. Real-time results from the OPAL-RT test bench and simulation have validated the proposed inverter. [ABSTRACT FROM AUTHOR]

In recent years, a special attention is paid to grid connected multilevel converters. These converters have specific use in industry in a high power, medium-voltage and highvoltage applications. This paper presents new control algorithm for single-phase AC/DC modular multilevel converter with target application as a traction converter connected directly to trolley wire. The proposed control strategy presents resonant controllers for converter current control with fundamental frequency adaptation. The fundamental frequency estimation and voltage synchronization is based on Second Order General Integrator Phase Locked Loop (SOGI-PLL). Furthermore, this paper presents robust voltage balancing technique for multilevel converter based on energy calculation of DC-link capacitances. It provides voltage balancing of multilevel converter cells with unbalanced load. The resulting control algorithm has low total harmonic distortion of converter trolley current even under unbalanced load condition. The algorithm was experimentally verified on the low voltage laboratory prototype with 3 H-bridge cells. [ABSTRACT FROM AUTHOR]

To supply five-phase variable speed drives, five-phase voltage source inverters are used. Some of the applications of five-phase variable speed drives are traction, electric & hybridelectric vehicles, and ship propulsion. Different control systems are available for the controlled output of the five-phase VSI, but space vector pulse width modulation is popular because of its simpler digital implementation. In this paper, the SVPWM schemes have proposed and analyzed for the multilevel operation of a five-phase dual voltage source inverter. The proposed techniques do not contribute a voltage balancing issues such as in multilevel neutral point clamped (NPC) inverters. The author analyzed the performance of five-phase VSI based on THD and fundamental components. Matlab/Simulink model has provided for results verification. [ABSTRACT FROM AUTHOR]

In this work, the direct torque control (DTC) is applied to the five-phase permanent magnet synchronous motor (FP-PMSM). The DTC method based on classical space vector pulse width modulation (SVPWM) is a common solution used to overcome traditional problems; such as stator flux ripple, electromagnetic torque ripple and gives more total harmonic distortion (THD) of the stator current. The actual paper is based on improving the performance of DTC-SVPWM by using the feedforward neural networks (FNNs) instead of the proportional-integral (PI) regulators and hysteresis comparators (HCs) of the conventional SVPWM strategy. This algorithm can solve the traditional PI regulators and HCs problems which are represented in responses dynamic and reduce the torque ripple, flux ripple, and the THD of stator current of FP-PMSM drives. The proposed strategy was tested in different tests with simulation using Matlab software. [ABSTRACT FROM AUTHOR]

The conventional highly composite and interrelated power systems sometimes consist of thousands of buses and hundreds of alternators, which need improvement in electric power consumption, consistency maintains, and security. To meet the ever-growing good quality power demand, the improvement of conventional transmission methods and the formation of new concepts that might allow the optimum utilization of accessible power with no reduction of system reliability are of the utmost importance. But due to high complexity, these system responses are oscillatory in nature. If this system oscillation is damped somehow such that the system achieves a new steady operating condition within the transient period, then the system becomes stable. A stable power system requires that the system oscillations should die immediately. This paper proposed a novel control strategy based on a lead-lag based stable controller for a unified power flow controller (UPFC) for faster damping of inter-area oscillations of the system. Each design has been successfully simulated in MATLAB Simulink platform. [ABSTRACT FROM AUTHOR]

New photodetector structure combining thinned CdTe film with lead-free perovskite photoelectric film was produced and investigated. This setting of the CdTe thickness results in photodetector parameters' competitiveness to the state-of-the-art in the field of advanced photoelectric materials. The device shows a promising sensitivity of ~40 µA/W, maximum responsivity of 10.6 mA/W at 460 nm, equal rise and fall times of 30 ms, and high linearity (maximum linearization error is less than 0.6 %). However, the optoelectronic performance of CdTe/lead-free perovskite structures integrated with signal processing circuit remains unexplored. For this purpose, Field Programmable Analogue Array (FPAA)-based mixed-signal processing circuit is developed for pulse width modulated electrical signal with duty cycle controlled by the illumination degree of the detecting photoelement. This novel approach guarantees a smooth change of the electrical output at a smooth change of the input illumination between the light and dark switching states and can be practically applied as a precise position detector of moving objects. The paper represents a synergistic connection between microelectronics, electronics, and signal technology. [ABSTRACT FROM AUTHOR]

The dimensioning of photovoltaic systems is the major concern of researchers and power industry practitioners. This aims to improve energy efficiency and protect the conversion units by a consistent assessment of power conditioning circuits and interconnections for the PV application. In this context, this paper sets out to fulfill detailed modeling and control steps of a standalone photovoltaic (PV) power system with energy storage, according to practical specifications of the load, PV generation unit, and battery pack. The main goal is to estimate all unknown parameters, as the diode ideality factor and revers saturation current, the controller, and the PV link. The PV link interfacing the PV source circuit to the PV-side converter (PVSC) provides a filtering function to maintain a steady voltage at the link. The charge controller used in the PV-side converter is a DC/DC buck converter. It transfers the PV power to the battery and supplies the load. Using pulse-width modulation (PWM) technical, of which the switching duty cycle is the control-input variable; the PVSC power-conditioning circuit is permanently controlled by the maximum power point tracking (MPPT) algorithm to achieve the maximum energy. The battery pack voltage is properly maintained by the charge controller and specified to match the load voltage rating, to avoid a high ratio of voltage conversion. A method is proposed to integrate both the MPPT function and the battery cycle charge. The PV generator output and the power conditioning circuits, mainly constructed from switching-mode power converters, are nonlinear. An averaged model is then derived for dynamic analysis and controller synthesis, using the state-space averaging and linearization method. A PV array of nine PV modules configured into three strings is used in this application to demonstrate the effectiveness of modeling, design, control, and simulation. Simulation model for the controller and power interface is built and developed in short term, using the fundamental blocks of Matlab Simulink. [ABSTRACT FROM AUTHOR]

This paper presents the control of grid-connected single-phase inverters with vector control technology based on the D-Q spindle reference frame for photovoltaic systems. This method begins with converting the grid current of the reference sinusoidal signal to a 90-degree phase angle and converting it to a DC signal using the clack conversion principle. The aim of this research is to control the current amount of the D-axis vector and adjust the motion angle lag and lead the Q-axis vector. This mechanism control technology uses a microcontroller TMS3020F28379D This allows control of the inverter modulation to supply active and reactive power to the grid. As a result, the power factor in the system can be controlled close to unity. The simulation results using MATLAB / Simulink, compared to the prototype mechanism can confirm satisfactory accuracy. [ABSTRACT FROM AUTHOR]

In this paper, we report a smart street lighting control system using the ESP8266 which is a low-cost Wi-Fi chip with full TCP/IP stack and microcontroller capability. Our system is equipped with a web server developed in HTML code. Hence, our smart street lighting system can be controlled wirelessly to turn ON or turn OFF. Moreover, our system can monitor the environmental condition, that is the temperature and humidity parameters around the streetlight. All sensors used in this system are pure digitally-outputted sensor: DHT11 to monitor the ambient temperature and humidity and BH1750 to adjust the street light intensity automatically. The dimming technique was applied in the control system by using Pulse Width Modulation (PWM). The system was divided into two main parts: Gateway and Node in which these two parts employ the ESP8266. The Gateway as a coordinator will send a message to the node as an end device. In this work, the streetlight is set as a Node. Later, the node will send the ACK to the Gateway. Based on the performance test, we found that each node in the system can send a message to other nodes. [ABSTRACT FROM AUTHOR]

This paper present the improvement in integration of electrical grid and induction generator with self-excited mode. This induction generators are mostly used in wind turbine. For this purpose static synchronous compensator is adapted with direct adaptive strategy with some adjustable controller parameters and an adjusting mechanism to adjust them using model reference adaptive control (MRAC). Model reference adaptive control is used to balance reactive power flow of this integration. Voltage-source inverter sinusoidal pulse width modulation handles the different operational condition in wind energy system. According to that ability of staying connected with grid in Brownout and blackout also increases. Because of occurrence of some faults at coupling of grid and generator, some abnormal operational condition generates. In proposed model, Genetic Algorithm with modified mutation function is used to tune proportional-integral controller. Instead of conventional random selection function for mutation, a modified algorithm is applied. For evaluation purpose Zafarana wind system integrated with Egyptian 220 networks is used. Results shows an improvement in performance of proposed model reference adaptive control using genetic algorithm which balances the current, voltage and speed of wind generator. It is also observed ability of staying connected with system under abnormal situation and during Brownout and blackout also increases with segmented mutation based genetic algorithm. [ABSTRACT FROM AUTHOR]

Wind energy conversion systems employ the doubly fed induction generator (DFIG) for maximum energy capture. Many traditional systems used pulse width modulation (PWM) technique to control the DFIG block by a feedback from the load terminal. PWM schemes generate the control pulses for an inverter switches. An independent activation of the wind turbine generator does not offer optimum result. This paper presents the fuzzy-based PWM controlling of wind turbine system in DFIG to provide an optimum result. According to the torque level and the rotation speed of wind turbine, the speed of the generator is controlled to maintain voltage regulation at load side. The integration of ABC-direct quadrature transformation based on the fuzzy rule generates the necessary control signals for gates. To control the operation of multilevel converters, an enhanced phase differential space vector PWM modulation (EPD-SVPWM) is implemented in this paper. The transfer function for maintenance of the reduced level of ripples in inverter switching circuit included in the modification of SVPWM lead to high-speed switching of the insulated gate bipolar transistor (IGBT). Consequently, it results in a low error rate and regulated power at load side. The experimental results exhibit better performance regarding dynamic voltage variation impact, and output voltage level at load side than the existing methods. [ABSTRACT FROM AUTHOR]

The paper describes various modified algorithms of classical sinusoidal pulse width modulation (PWM) serving for a three-phase two-level inverter control. The paper presents the results of a research of 3 PWM versions with varying duty cycle parameters and frequency of the pulse signal modulation. The method is to divide the modulated sinusoidal signal cycle (half-cycle) into intervals in order to change the modulation frequency within the separate sectors of forming the quasi-sinusoidal output voltage waves. In addition, algorithmic ways to compensate the additional losses in the inverter and the induction motor at high modulation frequencies of a discrete control signal are investigated and described in the paper. Calculations and simulations are performed by NI Multisim simulation program and NI LabVIEW visual programming environment. Theoretical studies are performed using the electric drive theories, discrete control systems and spectral analysis. The practical implementation performed by Texas Instruments Stellaris Launchpad using the Energia prototyping platform, field-programmable gate arrays (FPGA) of National Instruments CompactRIO-9074 and NI Single-Board RIO GPIC (sbRIO-9606, NI 9683 (GPIC), LX45 FPGA) using NI LabVIEW software and add-on modules (LabVIEW Real Time, LabVIEW FPGA). The suggested inverter control methods make it possible to reduce the distortion of the output quasi-sinusoidal signal and reduce the power consumption of the DC link while significantly reducing the number of inverter transistor switching in comparison with the classical method without premodulation or technical devices (filter-compensating devices). [ABSTRACT FROM AUTHOR]

This paper presents the modeling and controlling the power of Quasi Z-Source cascaded H-bridge multilevel inverter for grid connected photovoltaic systems. The Quasi Z-Source inverter is an inverter that provides buck / boost output along with DC-AC conversion in a single stage. This topology has numerous advantages which makes it reliable and suitable for PV applications. Due to the impedance network and the cascaded H-bridge structure, it provides high gain, reduced total harmonic distortion (THD) and high reliability in PV systems. In this paper, a five level cascaded H-Bridge Quasi Z-source inverter has been considered for which the impedance network has been designed. Phase Shifted Inverted Sine carrier pulse width modulation has been implemented along with shoot- through control for controlling the switches of the inverter. The closed loop power control scheme has been implemented in two stages. In the PV input side, each string voltage is controlled by adjusting the shoot-through states of the inverter using Independent Maximum Power Point Tracking Control. DC link voltage of each bridge has been balanced by using DC link voltage control. Both of these controlling actions result in the control of grid injected power. A 2kVA PV inverter has been designed and built using MATLAB/SIMULINK and the hardware has been completed for the open loop control. The simulation and open loop hardware results are discussed. [ABSTRACT FROM AUTHOR]

As a novel voltage control device, electric spring (ES) can effectively suppress the voltage fluctuations across critical loads (CLs), and solve the various problems with electrical quality induced by the grid access of renewable energy resources (RES). However, the traditional controllers for the ES system can no longer meet the control requirements, as the environment is complicated by the growing number of load-side nonlinear loads and uncertain disturbances. To solve the problem, this paper proposes a control system based on finite control set-model predictive control (FCS-MPC), and applies it to the ES. Firstly, a load-side circuit prediction model was established and analyzed. Next, a control system was designed based on FCS-MPC. Finally, the proposed system was proved feasible and effective through MATLAB/Simulink simulation and dSPACE physical experiment. The results show that the proposed FCS-MPC system can directly control the ES, easily handle system constraints, achieve robust dynamic and static performance, eliminating the need for pulse width modulation (PWM). [ABSTRACT FROM AUTHOR]

In this paper, two techniques are introduced to transform an uncertain second-order non-affine system under input saturation to an equivalent affine model. First, this affine model is obtained using the linearization technique with respect to the system inputs. In the case of the system being non-differentiable or its derivative with respect to the input being zero, this technique cannot be used. Then, to cope with this problem, an average dynamical model is suggested using the Filippov's model and the pulse width modulation. Afterward, an adaptive sliding mode controller is designed to overcome the approximation errors appeared in this transformation and inherent system uncertainties. Stability analysis is also derived using the Lyapunov theory. Ultimately, the capability of the proposed method is shown through MATLAB simulations. [ABSTRACT FROM AUTHOR]

Under unbalanced grid conditions, the DC side voltage of pulse width modulation (PWM) rectifier will overshoot during start-up and reference voltage transients, which may lead to system instability. In this paper, a deadbeat predictive power control (DPPC) with fuzzy PI compound controller (FPCC) and power predictive corrector (PPC) is proposed to solve that problem. Firstly, the parameters of the PI controller are adjusted online by the fuzzy control rule of the FPCC to eliminate the overshoot of the DC side voltage and contribute to faster dynamic responses, which thereby could correct the reference active power. Secondly, the static error between the reference and system active powers is reduced by accumulative predictive errors in the PPC. The simulation is carried out under ideal and unbalanced grid conditions. The result shows that the proposed control scheme can effectively eliminate the overshoot of DC voltage, reduce the static error of active power, and improve the dynamic response and anti-interference ability of the rectifier. [ABSTRACT FROM AUTHOR]

In this paper the Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) technique with considering controllable DC link voltages is implemented in the cascaded multilevel inverter. The novelty of this work is the method of mathematical modelling of SHE-PWM with respect to variable voltage of DC links. With respect to variable voltage of DC links, the number of degrees of freedom are increased compared to ordinary SHE techniques with constant voltage of DC links. One of the issues in SHE-PWM technique is solution of nonlinear equations under various operating conditions of the converter. In the proposed formulation, the resulted nonlinear equations are solved only one time for entire reachable range of output voltage amplitude, which leads to considerable reduction of computational burden. Also, the THD of output voltage waveform remains constant at minimum value for different operating points. The theoretical results of proposed technique are verified by the simulation and scale-down experimental setup of a cascaded 7-level inverter. [ABSTRACT FROM AUTHOR]

A novel technique to control the speed of BLDC motor and to maintain the power quality fed directly from the grid using a single stage Direct Matrix Converter (DMC) instead of using back to back converters is presented in this paper. The main advantage of using the DMC is the reduction of switches at the converter stage to nine as compared to twelve in case of back to back converters and hence results in a reduction of losses. Also, the system becomes robust with the removal of the bulky dc-link storage capacitor and provides all silicon solution to the controller part of the motor. The use of SVM at the grid side of the converter gives an improved input power factor with low distortion. The indirect modulation method of matrix converter gives the flexibility to apply closed-loop hysteresis current control at the load side of the converter for efficient speed control of the motor. The simulation results verify the efficiency and effectiveness of the proposed technique carried out in MATLAB/Simulink platform. [ABSTRACT FROM AUTHOR]

The radio frequency spectrum, which has been steadily getting smaller, is under pressure from growing cellular data traffic. A more dependable communication channel is required. To setup the communication medium, VLC uses LED illumination. In order to increase network throughput, the goal of this study is to analyze and model signal conditioning techniques in the visible spectrum. VLC technology offers synchronized illumination of LED lamps as well as wireless broadband connectivity. Using the real-valued O-OFDM baseband signal, optical orthogonal frequency division multiplexing (O-OFDM) offers a viable modulation option for very-low-bit-rate (VLC) systems to modulate the optical carrier's instantaneous power to attain gigabit data rates. However, one important design difficulty preventing VLC from being commercialized is how to combine industry-favored pulse width modulation (PWM) dimming technology while retaining a dependable, broadband connection. In this paper, Reverse Polarity optical orthogonal frequency division multiplexing (RPO-OFDM) is proposed as a new signal format for combining the fast O-OFDM contact signal with the comparatively slow PWM dimming signal, as both signals contribute to the illuminative brightness of the LED. The average SNR, additional testing demonstrates that the suggested method outperforms the Asymmetrically clipped optical OFDM (ACO), Optimized Flipped Optical (OFO) and DC biased optical OFDM (DCO), and algorithms in similar operating conditions. [ABSTRACT FROM AUTHOR]

The paper considers recent trends in the development of electrically operated hydraulic drive. The main requirements to the dynamic characteristics of variable axial piston pumps with electric control and the need for search of ways of their improvement are specified. The investigation results show the dynamic characteristics of the process to control electro-hydraulic axial piston pump capacity at different parameters of pulse width modulation (PWM) signal. The regularity between PWM-signal frequency and the time of establishing the proper pump displacement was found. The paper stresses the need for more detailed study of this fact and its usage for the optimization of variable pump regulation speed in order to be applied in electro-hydraulic flow control systems. [ABSTRACT FROM AUTHOR]

This paper presents the modeling and controlling the power of Quasi Z-Source cascaded H-bridge multilevel inverter for grid connected photovoltaic systems. The Quasi Z-Source inverter is an inverter that provides buck / boost output along with DC-AC conversion in a single stage. This topology has numerous advantages which makes it reliable and suitable for PV applications. Due to the impedance network and the cascaded H-bridge structure, it provides high gain, reduced total harmonic distortion (THD) and high reliability in PV systems. In this paper, a five level cascaded H-Bridge Quasi Z-source inverter has been considered for which the impedance network has been designed. Phase Shifted Inverted Sine carrier pulse width modulation has been implemented along with shoot- through control for controlling the switches of the inverter. The closed loop power control scheme has been implemented in two stages. In the PV input side, each string voltage is controlled by adjusting the shoot-through states of the inverter using Independent Maximum Power Point Tracking Control. DC link voltage of each bridge has been balanced by using DC link voltage control. Both of these controlling actions result in the control of grid injected power. A 2kVA PV inverter has been designed and built using MATLAB/SIMULINK and the hardware has been completed for the open loop control. The simulation and open loop hardware results are discussed. [ABSTRACT FROM AUTHOR]

Selective Harmonics Elimination Pulse width modulation (SHE PWM) presents an alternative modulation technique to operate medium voltage medium and high power converters as it reduces the switching losses. SHE PWM generates high-quality output waveform at the low switching frequency. Its application to multilevel converters furthers leads to improvement in output waveforms with lower switching losses, lesser dv/dt and lowers switching devices ratings. In this Paper SHE PWM for an asymmetrical cascaded H-bridge multilevel inverter under unequal DC voltage condition for fundamental and multiple switching cases are investigated. More harmonics can be eliminated by considering multiple switching's. The Solution of the Nonlinear transcendental SHE equation is obtained using an advanced derivative free numerical technique which. The method is simple in implementation with fast calculations per iteration as it avoids the evaluation of Jacobian and its matrix. Also the need for precise initial guess in the proximity of actual solution is not needed as an identity matrix of the size of designed variable serves the purpose. Different inequality in the dc voltages is taken to eliminate the lower order harmonics from the output. Only exact solutions for the switching angles which ensure the complete elimination of targeted harmonics are reported. Simulation and Hardware results are presented to confirm the validity of the proposed technique. • SHE PWM for an asymmetrical CHB MLI under unequal DC Sources for different switching cases are given. • The Solution of transcendental SHE equation is obtained using derivative free numerical technique. • Simple in implementation with fast calculations as it avoids the evaluation of Jacobian matrix. • The need for initial guess in the proximity of actual solution is not needed in the proposed technique. • Inequality in the dc voltages is considered to eliminate the lower order harmonics in output. [ABSTRACT FROM AUTHOR]

The use of phasor measurement units is becoming ubiquitous in modern power system as they provide dynamic monitoring of variables such as voltage and current, and also due to its capability to determine the variable positive sequence magnitude and phase. However, the increasing usage of renewables, DC grids, and power electronic devices may imply in a network environment contaminated with harmonics that might affect the correct estimation of positive sequence phasors values. This paper investigates the performance of a phase-locked loop (PLL)-based phasor measurement algorithm in a voltage and current harmonic polluted environment. PLL systems have been widely used for control of power electronics devices based on pulse-width modulation. There are in the literature several propositions of PLL architectures, and this work evaluates, among some of these possibilities, their adequacy for the aforementioned task. Detailed representation of the network elements involved is considered as well as a digital model for the PLL which can then assess its adequacy for real-time applications. [ABSTRACT FROM AUTHOR]

Multilevel inverters (MLIs) are an imperative solution for high power and high voltage applications. The MLIs can be classified into two categories such as symmetric and asymmetric. The asymmetric type MLIs has large number of output voltage steps with less number of input DC voltage sources and switching devices. In this paper, a single phase asymmetric (trinary sequence DC source) Cascaded H-Bridge MLI has been developed using unipolar PWM control schemes. The topology can produce 27-level output voltage with the help of 12 switches and 3 DC sources. It has been examined with a diverse combination of multicarrier unipolar PWM control. The PWM control includes Phase Disposition (PDPWM), Alternative Opposition Disposition (APODPWM), Carrier overlapping (COPWM), and Variable Frequency (VFPWM). The harmonic content of output voltage for each technique has been observed with different modulation indices. The demonstration of proposed topology for generating 27-level output voltage has been tested through simulation in MATLAB-SIMULINK and verified with laboratory-based experimental setup. From the results, it is evident that the APODPWM offers quality output voltage with relatively low harmonic distortion. Also, it has been observed that COPWM performance is superior since it delivers relatively higher fundamental RMS output voltage. [ABSTRACT FROM AUTHOR]

Abstract Pulse width modulation (PWM) AC–AC converter is a power electronic device which has many applications, because it can control the load voltage and active power. This converter cuts the voltage wave form, so the output voltage will have harmonics. Since the fundamental component of output voltage influences the active power, assigning weighting factor to the optimization problem of harmonic reduction in the converter has been proposed in this paper. To solve the optimization problem a hybrid algorithm including biogeography-based optimization BBO and simulated annealing (SA) has been presented. This algorithm has the advantages of the two method simultaneously. Since many evolutionary optimization algorithms may not reach the global optimum solution, in order to develop the search process, a local search algorithm in an inner loop i.e. SA is applied to the obtained solution by main search algorithm i.e. BBO. In the other word, the second level optimization by SA is applied to the best answer of BBO in each iteration, to find the global extreme point. The proposed algorithm has been applied to some standard benchmark functions. After validation using these problems, the main problem which is a practical problem to minimize the harmonics for PWM AC–AC converter has been solved. Simulation results show the efficiency of proposed method by considering weighting factor to optimize a practical problem in power engineering area in order to harmonic reduction as well as improving fundamental voltage as an important issue. Highlights • Developing a new optimization algorithm including both global and local search. • Proposing weighting factors for harmonics reduction optimization problem for AC–AC converter. • Obtaining optimal switching pattern for AC–AC converter by minimizing harmonics as well as maximizing the fundamental component of voltage. • Implementation the main purpose of using an AC–AC converter means controlling active power. [ABSTRACT FROM AUTHOR]

This paper describes research into a novel control strategy of traction converter for the AC-Trolley Line with the middle frequency transformer (MFT). Attention is paid to the problematics of finding a suitable control algorithm that will provide minimal magnetic saturation. This could be ensured by variable pulse widths, determined according to the actual value of input voltage. Special attention is focused on the single-phase matrix converter topology and the best commutation solution. Two basic methods of controlling the switches in the matrix converter are discussed. The first method requires some knowledge of the converter output current polarity and the second method assumes some knowledge of the input voltage polarity. In addition, the article describes the switching method in uncertain states - when the voltage or current cross zero. Moreover, the paper presents a new modular topology with several separate middle frequency transformers. The proposed algorithm is described and implemented in the laboratory model. [ABSTRACT FROM AUTHOR]

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