Multilevel Active Bridge (AB)-based converters are potential candidates for DC applications due to their ability to integrate multiple sources while minimizing volume. This paper presents an analytical and simulation-based investigation of circulating current behavior and power factor performance in AB-based multilevel converter structures. A High-Frequency Link (HFL) analysis framework is developed to characterize voltage, current, and power transfer waveforms, providing insight into reactive power generation and its impact on overall efficiency. By introducing a modulation-based control approach, the proposed converters significantly reduce circulating currents and enhance the power factor, particularly under varying phase shift conditions. Compared to conventional Quadruple Active Bridge (QAB) topologies, the discussed multilevel architectures offer reduced transformer complexity and improved power quality, making them suitable for demanding applications such as electric vehicles and aerospace systems.

This paper proposes a space vector-based pulse width modulation scheme that incorporates common-mode voltage elimination and bus clamping for a dual six-phase inverter configuration driving an asymmetrical six-phase motor with open-end stator windings. The proposed scheme completely eliminates the common-mode voltage generated by both inverters. Additionally, the employed switching sequence enables bus clamping, which reduces switching losses compared to conventional patterns. The clamping strategy also ensures balanced power loss distribution among the switching devices. By eliminating the resultant common-mode voltage, the scheme allows for the use of a shared DC-link between the two inverters. Furthermore, it suppresses non-torque-producing harmonics in the stator windings of the ASPM and achieves higher DC bus utilization compared to conventional six-phase drive configurations. The effectiveness of the proposed scheme is validated through extensive simulations conducted in the MATLAB/Simulink environment.

The need for sinusoidal voltage waveforms with adjustable amplitude and frequency is essential in many applications. Power electronics converter-based supplies with pulse-width modulation (PWM) introduce high-order harmonics at their output and the use of filters is mandatory to remove the harmonic distortion. However, output filters are undesired in some specific applications such as B-H meter of magnetic devices because they act as the inverter output load together with the actual load affecting the measurement results. This paper explains the principles of operation and design considerations of a controlled AC power supply with nearly sinusoidal output. The proposed AC power supply consists of switching-mode DC-DC converters connected at the DC links of asymmetric cascaded H-bridges (ACHB). The proposed AC power supply offers a nearly sinusoidal output even at high-current low-voltage outputs. A modular compact 63-level supply is designed for the special case of the B-H meter and the simulation results are presented.

Proportional-resonant and repetitive controllers are widely used for grid current control in single-phase grid-connected inverters. This paper presents a comparative study of the performance of these two controller types in mitigating low-order harmonics with a descriptive analysis of their design. Moreover, low-order harmonics arising from the dead time in single-phase highly efficient and reliable inverter concept (HERIC) are investigated. Then, a novel scheme based on the harmonic decoupling network and second-order generalized integrator is designed to extract the low-order harmonics from the grid current. These extracted components are subtracted from the reference current to efficiently attenuate the low-order components. Experimental studies show an efficient mitigation of the low-order harmonics with the proposed scheme.

Lithium-ion (Li-ion) batteries are the preferred choice for energy storage applications. Li-ion performances degrade with time and usage, leading to a decreased total charge capacity and to an increased internal resistance. In this article, the wavelet analysis is used to filter the voltage and current signals of the battery to estimate the internal complex impedance as a function of state of charge (SoC) and state of health (SoH). The collected data are then used to synthesize a battery digital twin (BDT). This BDT outputs a realistic voltage signal as a function of SoC and SoH inputs. The BDT is based on feedforward neural networks trained to simulate the complex internal impedance and the open-circuit voltage generator. The effectiveness of the proposed method is verified on the dataset from the prognostics data repository of NASA.

This paper introduces a new soft-switched high gain converter topology with Input Current Smoother (ICS) capability to mitigate Normalized Peak Inverse Voltage (NPIV). By employing soft switching techniques, the converter achieves significant reductions in switching losses and improved overall efficiency, making it ideal for high-frequency applications. The proposed converter enhances voltage gain while minimizing voltage stress on power semiconductors, overcoming the limitations of conventional step-up converters. The paper provides a detailed description of the converter's operation principles, configuration, and steady-state analysis. Performance comparisons with existing topologies demonstrate superior voltage gain, minimized voltage stress on semiconductors, negligible input current ripple, and remarkable efficiency. Finally, simulation results demonstrate the advantages of the proposed converter by using PSCAD software.

A virtual voltage vector based direct torque control (DTC) scheme with enhanced DC bus utilization for an asymmetrical six-phase induction motor (ASPIM) with open-end stator windings is proposed in this paper. In this scheme, the voltage vectors generated by two six-phase, two-level voltage source inverters (VSI) connected to both sides of the stator windings are combined to obtain a virtual voltage (VV) space vector structure in the ASPIM. While generating the virtual voltage vectors it is ensured that the following three conditions prevails in the system: 1) elimination of resultant common mode voltage (CMV) across the stator windings, 2) elimination of triplen order harmonic voltages from the individual 3-phase windings, and 3) nullification of non-torque producing harmonic voltages. Conditions 1 and 2 facilitate the use of a common DC-link for both the VSIs without causing circulation of common mode currents through the stator windings. The third condition obliterates the large, non-torque-producing harmonic currents and consequent losses in the system. The proposed scheme can provide significantly higher DC bus utilization compared to the conventional schemes, for the same DC-link voltage. The effectiveness of the proposed scheme is verified by carrying out simulations using MATLAB-Simulink software, under transient and steady-state operating conditions of the drive.

Voltage spikes during the switching transients play an important role in determining the power losses in hard-switching converters. These spikes are functions of several factors at the instant of switching such as DC-link voltage, load current, transistor and diode switching delay times, reverse recovery current of the diode, parasitic capacitance and inductance of the circuit. This paper introduces a numerical approach to accurately model the switching power losses of a single-phase H-bridge (SPHB) inverter. The data required to obtain the equivalent resistance is extracted from the experimental double-pulse tests (DPTs). Then, the concept of local and global rms currents is considered to incorporate the effect of pulse width modulation (PWM) in the estimation of the switching losses. The results are computed for unipolar and bipolar PWM schemes. Finally, the reflection rule is utilized to obtain an equivalent output resistance for the inverter switching losses.

We consider the tracking control problem for a class of stochastic nonlinear systems in strict-feedback structure via output feedback signal in this article. The controlled plant is assumed subject to unknown dead-zone input. By utilizing the fact that the unknown dead-zone input function can be modeled as a time-varying nonlinear function and a bounded disturbance, and selecting appropriate design parameters, we show that the effect of unknown dead zone can be compensated. We design a fuzzy state observer via fuzzy logic modeling technique to estimate the unknown system states. Then, we prove, via Lyapunov stability analysis, that the controlled plant is bounded in probability. In addition, all the signals in the closed-loop system are guaranteed to be globally bounded in probability. The tracking errors are also ensured to converge to a small neighborhood of the origin. Finally, to show the effectiveness of the proposed control strategy, a simulation example of one-link manipulator is presented in the simulation section.

Finite Control Set Model Predictive Control appears an interesting and effective control technique for Cascaded H-Bridge converters but, because of its computational complexity, becomes impractical when the number of levels of the converter increases. This paper proposes a Neural Network-based approach capable of overcoming the computational burden of conventional predictive control algorithms. The proposed control is then applied to a Cascaded H-Bridge Static Synchronous Compensator using FPGA and tested via hardware in the loop. Results and analysis demonstrate that optimal control of multilevel converters with many levels can be obtained with low computational effort.

Compared to bipolar, unipolar PWM (UPWM) is advantageous for switching the single-phase H-bridge inverter as it generates an output differential voltage with lower THD. However, the oscillatory nature of the common-mode voltage in UPWM contributes to the ground current in single-phase grid-connected PV inverters, which is the motivation of the various transformerless inverters with UPWM. Although, the benefits of UPWM (mainly the good characteristics of output differential voltage) in existing transformerless inverters is somehow missing. In this paper, after analyzing different switching schemes of HERIC (highly efficient and reliable inverter concept) converters, a modified UPWM is proposed in which the full sawtooth carrier and sinusoidal reference waveforms (changing between negative and positive maximums) are compared in order to increase the number of voltage pulses and reduce the THD of grid current. The superiority of the proposed UPWM has been confirmed by comparative simulation studies over a 1-kW single-phase grid-connected PV inverter.

In this paper, a complete model of faulty multiphase permanent magnet synchronous machines (PMSMs) is presented in phase domain when the machine is fed by voltage-source inverters (VSIs). The presented model is helpful for implementing the simulation model of the machine when it is supplied by voltage inputs. Then, an orthogonal fault-specific transformation matrix is introduced to acquire the machine model in vector-space decomposition (VSD) domain. This model is helpful in the sense that it establishes mathematic relations between the stationary components of machine currents in multi-star (MS) and VSD domains. Based on these relations and along with transformation of VSD components to synchronous and anti-synchronous reference frames, a current sharing strategy is obtained to distinguish the contribution of each three-phase winding set to the developed torque under faulty conditions. The reference values in VSD domain are set so that the lowest ohmic losses are dissipated under faulty conditions.

In this paper, a software-based resolver to digital converter (RDC) is proposed. The hardware signal conditioning circuit is realized using common electronic components, while the algorithm can be implemented either using a microcontroller or an FPGA. Its validation and performance analysis has been carried out using an interior permanent magnet synchronous machine drive and, with comparative purposes, an LTN Servotechnik 1024 ppr incremental encoder. Tests show that the proposed RDC is characterized by a good dynamic response and precision, moreover, due to low computational demand, it can be successfully adopted without significant extra cost.

Lithium-ion batteries have high energy density, lightweight and long life cycle, thus they are the choice for powering electric vehicles. The needed high voltage battery pack is achieved using series-connected cells, that ideally should be identical. However, parameter variations of cells in EVs, along with different working conditions can cause State of Charge (SoC) and temperature imbalances that shorten battery lifetime. Moreover, a series connection can potentially be exposed to single-cell failure. This paper proposes a redundant smart battery topology based on the series connection of individual cell modules. Each module is formed by a cell with an insertion/bypass circuit and a wireless processor that monitors cell states and communicates with a Master controller. To synthesize the nominal voltage, a battery pack with a small redundant number of cells is considered. In this way, it can be made both fault-tolerant and reach higher safety. The problem is then shifted to the control algorithm that at each sampling time has to select "n" cells out of the total cells, according to some goals. A Machine Learning-based control algorithm was developed and tested in Matlab to insert/bypass the cells and reach simultaneous balancing of both SoC and temperature. The new method based on the K-nearest algorithm has been compared in simulation with a conventional sorting balancing method and showed superior performance, especially in temperature balancing.

Several modelling approaches of multiphase machines have been proposed in literature to control the machine in healthy or faulty conditions. The variety of the models may confuse the researchers to select the proper ones. In this paper, vector space decomposition (VSD), multi-star (MS), and decoupled MS (DMS) models are developed with detailed explanations for triple three-phase (or asymmetric nine-phase) permanent magnet synchronous machine (PMSM). It is shown that the machine differential equations are not fully decoupled in DMS modelling. The presented approaches can be extended to any types of multiple three-phase PMSM. Also, two new models are introduced with the use of specific transformation matrices in order to provide the current sharing between different three-phase winding sets and for compensation of current harmonics arising from inverter nonlinearities or machine structure. These models are necessary to design the parameters of the control system in order to have the optimum dynamic response.

Cascaded H-Bridges Multilevel Inverters are an innovative and promising solution in different application fields. This topology allows obtaining an improvement in the performance (e.g. reduced harmonic content, the low voltage stress on power components, and high efficiency) in respect to the traditional two-level inverters. In this context, the Multicarrier-PWM strategies play an important role thanks to their features. This paper presents an experimental investigation on the performance of a three-phase five-level Cascaded H-Bridge inverter by using different PWM modulation strategies. In particular, the paper is focused on the experimental validation of the main features of Multicarrier PWM taken into account by varying the modulation index and the switching frequency.

Finite Control Set Model Predictive Control is an effective technique which attracted attention in the latest years thanks to its fast dynamic response and the fact that it does not require a modulation. However, when applied to multilevel converters, it requires a large amount of calculations that may affect implementability. On the other hand, Neural Networks are well known Machine Learning techniques that can be efficiently implemented in real-time applications thanks to their massive parallelism capability. This work proposes a novel Finite Control Set Model Predictive Control approach based on Neural Networks with reduced computational time complexity for a Cascaded H-Bridge Static Synchronous Compensator. Simulation results for a nine-level system are presented and a simulative comparison between our approach and classical methods for FCS is provided, showing that very similar performance can be achieved with strong reduction of the computational complexity.

Multi-phase AC drives have gained interest and popularity in the research field of full-electric aircraft (FEA). Without excessive complication, they improve highly relevant aspects of the drive including fault-tolerance, which is crucial for air transportation. In this paper, a novel concept is proposed for the electric propulsion system for the aircraft, combining the redundancy of a six-phase Permanent Magnet Synchronous Motor with the modularity of multilevel cascaded H-bridge converters. The proposed system increases the flexibility, performance, and reliability of the electric power train. A mathematical model of the drive has been set up and some simulations exploiting different operating modes have been successfully carried reporting the main results in this paper.

This paper considers single phase seven-level cascaded H-bridge (CHB) inverters for Uninterruptible Power Supplies (UPS) applications and proposes a fundamental switching frequency procedure, based on graphic analysis, to improve the output waveform quality. It fixes the first switching angle and gets the other two by intersection of harmonics functions set to zero. The performances of the proposed procedure, in terms of total harmonic distortion (THD), are compared with those obtained by a procedure that identifies the two remain optimal switching angles through a THD minimization algorithm. Experimental results are obtained by measurements performed on a prototype built at DigiPower laboratory. The agreement between computed and experimental results confirms the accuracy of the presented procedure.

Multilevel converters prove to be well-suitable for high and medium voltage systems due to their lower cost and high-redundance design. For STATCOM, Single-star Bridge-cell (SSBC) topology is well applied for its satisfactory performance and superior component count. However, when number of levels increases, more switches are required to be parallelly controlled. Therefore, software-based microcontrollers (e.g. DSPs) shows limitations in terms of I/O built-in pins as well as performance. Alternatively, field programmable gate arrays (FPGAs), with their parallelism capability, are suitable for implementing control of SSBC-STATCOM. Multilevel SSBC-STATCOM control is composed of three layers which are output voltage control layer, internal current control layer and capacitor voltage balancing layer. A dq control based on PI regulators are commonly used for its simplicity and ease in implementation. In this work, detailed control design and implementation of SSBC-STATCOM using FPGA is discussed. Cyclone V FPGA with 50 MHz clock was used to implement control blocks and a hardware set-up of 142 V SSBC-STATCOM was designed to verify the results.

This paper proposes an efficient analytical harmonic elimination procedure valid for cascaded multilevel converters having s dc sources and a number of level l = 2s+1 with s = 2nn = 1,2,3, .... This procedure eliminates n+1 harmonics and their respective multiple; this implies a very low Total Harmonic Distortion. A 9-level inverter prototype is built and experimental results are obtained. The accuracy of the presented procedure is proved by the agreement between computed and experimental results.or, is observed.

With more installation of electronic loads and of distributed renewable energy sources, static compensators gain more interest to encounter the resulting power quality issues in low and medium voltage grids. Traditionally, two-level inverter topology, is utilized for this application, eventually with transformer at medium voltage. However, due to the low harmonics performance and the requirement for bulky filtering, the multilevel converters topologies become more attractive. Different topologies have been introduced during the last few decades and among the others, the Single-Star bridge cell is well applied to this application for its satisfactory performance and superior component count. Generally, the feasibility of adoption of static compensators for low and medium voltage systems relies strictly on their performance and cost-effectiveness. Theoretically, the harmonics performance improves with increasing the number of levels. However, this has a direct effect on their design and hence on their overall complexity and cost. In authors' knowledge, no paper has extensively discussed the impact of the number of levels on the cost of static compensators. Thus, this paper investigates some key factors in STATCOM design with emphasis on their impact on the overall cost in low and medium voltage applications.

This paper proposes a comprehensive analysis of switched boost inverter's (SBI) voltage and current equations, using specific switching method in continuous current mode (CCM) operation. The presented switching method makes SBI proper to be used in galvanic and electrochemical applications. The boundary amount of inductor between the two CCM and discontinuous current mode (DCM) operations is calculated and also the operative parameters are determined. In addition, the diodes' and switches' voltage and current stresses, the inductor's current ripple and the capacitor's voltage ripple equations are represented which are needful to design the components. Moreover, the switching control circuit is proposed. Finally, the PSCAD/EMTDC software program results are given to show the theoretical analysis validation.

Smart Grid improves the electricity grid infrastructure by introducing new powerful communication system between consumer and supplier. Implementation of smart meters increases the availability of detail level of consumer electricity load profile data. To improve and efficient planning and development of this new power system, a primary challenge is to analyze the electricity consumption data. To analyze the energy consumption or achieve our objective we choose the best analytic process is data mining techniques including exploratory data analysis and preprocessing, frequent patterns mining and associations, classification /characterization,clustering and outlier deduction. In this paper, we use these techniques and apply on two different public available datasets. Explain and evaluate which techniques is use full for the better understanding of electricity load profile consumption data.

This study suggest a new basic structure for symmetric and asymmetric cascaded topologies with reduced number of power electronic components. This topology generates 10 voltage steps by three unequal dc voltage sources and seven switches. The suggested topology creates just positive and zero voltage steps and it needs to one H-bridge to generate negative voltage levels. Based on the located H-bridge, two different cascaded multilevel topologies are proposed. Also, various methods to specify the magnitudes of dc voltage sources are suggested. The proposed cascaded multilevel inverters in comparison with the conventional cascaded topologies and other new topologies which presented in literature decrease the number of components such as, IGBTs, switches, driver circuits and DC links. PSCAD/EMTDC simulations results of 19-level inverter are presented to reconfirm the correct performance of the suggested topologies.

In order to guarantee the proper operation of grid-connected power converters, a correct synchronization with utility networks is required to extract quickly and precisely the fundamental signal. This paper presents an experimental verification of the performance of an architecture called Generalized filtering Enhanced Phase-Locked Loop, proposed in [1] to detect the amplitude, the frequency and the phase of a sinusoidal signal from a noisy measurement. The considered application regards the synchronization of the power converters with the utility network. The GEPLL scheme is characterized by an error filter and a phase-feed forward term that are embedded in the estimation algorithm for improved noise rejection and transient performances. By properly selecting the transfer function of the error filter the transient dynamic performance is improved. The presence of measurement bias and the effect of high frequency noise and harmonics are taken into account by suitably selecting the parameters of the Phase Locked Loop. Both the single and three phase grid connected power inverter systems are considered. The comparison with the original Enhanced Phase- Locked Loop shows the superior performances of the proposed Generalized filtering Enhanced Phase-Locked Loop.

This paper presents a seventeen level inverter topology for open end induction motor drives requiring only twelve switches per phase. One three-level inverter and one seven-level inverter with DC link voltages in 3∶1 ratio are connected to the two ends of the stator winding of the induction motor to generate a seventeen level space vector structure. A level shifted carrier based scheme is used to modulate the inverter, which requires only instantaneous phase voltage references. Selection of switching states is used to ensure that both inverters supply real power to the motor the over entire modulation range, preventing overcharging of the DC bus. The topology was tested for steady state operation over the entire modulation range, and experimental results are included below.

Compensation is a vital part in Inductively Coupled Power Transfer (ICPT) to achieve higher efficiency, power density and reliability. This article proposes two unilateral LC compensation topologies for ICPT system after thorough theoretical analysis, which achieve both zero-voltage switching and constant voltage output characteristics over a wide range of load. A 300W phase-shifted full bridge DC-DC Wireless Power Transfer device is designed and built which achieves an efficiency of 87.8% using proposed structure.

During a few decades many multilevel topologies have been proposed. Contemporary research has engaged for new multilevel inverter topology by unique circuits. This paper presents a new sub-module inverter for cascaded multilevel inverters with reduced number of count. The recommended inverter generates 17 step by four DC links (only two DC link are unequal) and 8 power switches. The suggested sub-module inverter generates all voltage levels (positive, negative and zero) at the output without any additional circuit. Also, a cascaded connection for suggested structure is proposed. The advantages of the suggested cascaded connection are reduction number of components such as semiconductor switches, driver, IGBTs, the variety of the value of DC links and DC links in comparison with classical cascaded structures and other new structures which presented in literatures. For specifying the magnitudes of the DC links three new methods are calculated in order to produce more voltage steps, too. PSCAD/EMTDC simulation outcome are demonstrated to confirm the suggested structure excellent operation.

This paper presents an overview and experimental analysis of the MC SPWM techniques for single-phase cascaded H-bridge inverter. The multilevel power converters are an alternative to traditional converters known as “three-level converters”. The voltage waveforms and the related frequency spectra, which have been obtained by simulation analysis in Matlab-Simulink environment, are here reported for all the proposed modulation techniques. The simulation results have been experimentally validated through means of a DC/AC, five-level, single-phase converter prototype with an appropriate test bench.

This paper proposed one novel control method for modular multilevel converter(MMC) to tackle its low frequency operation problems as the module capacitor voltage ripples. Comparing with conventional control, this paper proposed one asymmetric control by alternating work sates of upper and lower arms, to achieve excellent capacitor voltage ripples suppression effect. To avoid the limited modulation range and enhance performance, hybrid or full bridge MMC structure is employed. The detailed control is analytical discussed, with full simulation results to verify the proposed methods.

The papers in this special section focus on the topic of industrial sensing intelligence. Examines the sensor and communications technologies that support these services and reports on industrial applications for their use.

This paper investigates about the impact of the number of levels and of the corresponding modulations angles on the mitigation of harmonics in cascaded H-bridge multilevel inverters. A mathematical model to reduce Nth odd harmonics from the output voltage of a multilevel converter is represented as a constrained optimization problem. It is further transformed in an unconstrained optimization problem that can be solved more simply by using the particle swarm optimization method. By varying the modulation index, the procedure guarantees the constancy of the output voltage amplitude.

In this paper, a grid connected shunt converter for mitigation of voltage sags in weak grids is described. The VSC keeps the grid voltage magnitude at the point of connection constant by injecting reactive power to compensate for the voltage dip. A novel flatness-based control (FBC) is proposed for this purpose that gives higher performance and robustness with an inductor/capacitor/inductor (LCL)-filter in between the VSC and the grid. Simulation model includes the practical limitation of voltage source converter output voltage. Then, the simulation results for the FBC under balanced voltage dips are presented and compared with traditional proportional integral controller. Finally, the sensitivity analysis of the FBC for grid impedance and to system parameter variations is presented.

A method to obtain pulse width modulation (PWM) timings for a three level dodecagonal (12-sided polygon) voltage space vector structure using only sampled reference values is proposed in this paper. Typical methods that are used to find PWM timings for dodecagonal SV structures use modulation index and the reference vector angle to get the timings by using trigonometric calculations. This method requires look-up tables, angle estimation making it difficult to implement in closed loop systems. The proposed method requires only two additions to compute these timings. For multilevel case, typical iterative methods need timing calculations (matrix multiplications) to be performed for each triangle within a sector. The proposed method does not require any iterative searching for locating the triangle in which the tip of the reference vector lies. It is also is generic and can be extended to any number of levels with symmetric structures. The algorithm outputs the triangle number and the PWM compare values - that can be used by any carrier based PWM module to obtain space vector PWM like switching sequences. Extensive simulation and experimental results for steady state and transient conditions have been presented to validate the proposed method.

To assure power quality and stability of the electricity network it is important to perform control and synchronization of the inverters which are used in the connection of distributed DC power generation units to the grid. It is proven that the model of the inverters, is a differentially flat one. By exploiting differential flatness properties it is shown that the multiple inverters model can be transformed into a set of local inverter models which are decoupled and linearized. For each local inverter the design of a state feedback controller becomes possible, e.g. using pole placement methods. Such a controller processes measurements not only coming from the individual inverter but also coming from other inverters which are connected to the grid. Moreover, to estimate the non-measurable state variables of each local inverter, the Derivative-free nonlinear Kalman Filter is used. This consists of the Kalman Filter recursion applied to the local linearized model of the inverter and of an inverse transformation that is based on differential flatness theory, which enables to compute estimates of the state variables of the initial nonlinear model of the inverter. Furthermore, by redesigning the aforementioned filter as a disturbance observer it becomes also possible to estimate and compensate for disturbance terms that affect each local inverter.

A deterministic algorithm aiming at reduction of harmonic content in three phase, five-level cascaded inverters is proposed. The procedure starts from a non-linear system consisting of disequations and, using Chebyshev polynomials and Waring's formula, for any assigned modulation index computes those switching angles α1and α2reducing harmonics amplitude such as to fulfill grid code specifications. Simulation and experimental results demonstrate the achievable results.

In this paper, a nineteen level dodecagonal voltage space vector structure is proposed for the first time, by cascading two asymmetric three level inverters with isolated H-Bridges. The dodecagonal structure is made possible by proper selection of DC link voltages and switching states of the inverters. The proposed scheme retains all the advantages of multilevel topologies as well the advantages of dodecagonal voltage space vector structure. A generic and simple method for calculation of PWM timings is proposed. Also, a new method of switching technique is proposed, which ensures minimum switching while maintaining the linearity between modulating signals and the output phase voltages. Extensive simulation and experimental results have been presented for validation of the proposed concept.

This research work introduces a new control method for feedback control of nonlinear power electronics systems with application example the problem of three-phase voltage source converters. The control method consists of a repetitive solution of an H-infinity control problem for the voltage source converter, that makes use of a locally linearized model of the converter and takes place at each iteration of the control algorithm. The converter's model is locally linearized round its current operating point through the computation of the associated Jacobian matrices. Using the linearized model of the converter an H-infinity feedback control law is computed. The known robustness features of H-infinity control enable to compensate for the errors of the approximative linearization, as well as to eliminate the effects of external perturbations. The performance of the proposed control scheme is validated analytically and is confirmed through simulation experiments.

This paper presents One-Cycle Control (OCC) of nine-level cascaded H-bridge inverter implemented in Altera FPGA Cyclone-III. The OCC, being a nonlinear technique, overcomes some problems related to nonlinear nature of switching power converters, thus allowing fast dynamic response and robustness to power source and load perturbations. An optimum power sharing strategy, among different modules of the multilevel inverter, is also presented that equalizes power sharing at the each H-bridge. After a description of the system some simulation results obtained in ModelSim are presented showing the effectiveness of the OCC which follows the reference signal, sinusoidal, in a concrete manner with the capability of regaining steady-state in just one switching cycle. There is neither dynamic error or steady-state error between the reference signal and the switched output.

Voltage source inverter (VSI) fed six-phase induction motor drives have high 6n ± 1; n = odd order harmonic currents, due to absence of back emf for these currents. To suppress these harmonic currents, either bulky inductive harmonic filters or complex pulse width modulation (PWM) techniques have to be used. This paper proposes a simple harmonic elimination scheme using capacitor fed inverters, for an asymmetrical six-phase induction motor VSI fed drive. Two three phase inverters fed from a single capacitor is used on the open-end side of the motor, to suppress 6n ± 1; n = odd order harmonics. A PWM scheme that can suppress the harmonics, as well as balance the capacitor voltage is also proposed. The capacitor fed inverters are switched so that the fundamental voltage is not affected. The proposed scheme is verified using MATLAB Simulink simulation at different speeds. The effectiveness of the scheme is demonstrated by comparing the results with those obtained by disabling the capacitor fed inverters. Experimental results are also provided to validate the functionality of the proposed controller.

The paper is concerned with proving differential flatness of the three-phase voltage source converter (VSC) model and its resulting description in the Brunovksy (canonical) form. For the linearized canonical model of the converter a feedback controller is designed. At a second stage, a novel Kalman Filtering method (derivative-free nonlinear Kalman Filtering) is introduced. The proposed Kalman Filter is redesigned as disturbance observer for estimating perturbations in the VSC model. These estimated disturbance terms are finally used by a feedback controller that enables the DC output voltage to track desirable setpoints. The efficiency of the proposed state estimation-based control scheme is tested through simulation experiments.

Information and communication technologies (ICT) represent a fundamental element in the growth and performance of smart grids. A sophisticated, reliable and fast communication infrastructure is, in fact, necessary for the connection among the huge amount of distributed elements, such as generators, substations, energy storage systems and users, enabling a real time exchange of data and information necessary for the management of the system and for ensuring improvements in terms of efficiency, reliability, flexibility and investment return for all those involved in a smart grid: producers, operators and customers. This paper overviews the issues related to the smart grid architecture from the perspective of potential applications and the communications requirements needed for ensuring performance, flexible operation, reliability and economics.

If properly controlled, LLC resonant converters can achieve zero voltage switching (ZVS) over the entire operating range, thus minimizing switching losses of the power MOSFETs and secondary diodes. For such a reason, this paper presents and compare a half bridge LLC resonant converter controlled by both an adaptive PID and a fuzzy logic controller (FLC). For obtaining the DC voltage transfer function, an analysis tool, the so called Fundamental Harmonic Approximation (FHA) method has been adopted. FHA is also used to determine circuit parameters and for predicting the transient response of the converter during sudden changes of input and load, which is then verified through simulations and laboratory measurements.

Power converters offer a high capability to efficiently manage electrical energy flows. Until a few years ago, their primary use was in supplying motors in industrial applications and in electric traction systems. Nowadays, in addition to those fields they are employed in a very wide range of low, medium, and high power applications including residential applications, renewable energy systems, distributed generation, and automotive. Since digital control represents a key element of modern power converters, this paper presents a review on digital devices [microcontrollers, Field Programmable Gate Arrays (FPGA)], hardware and software design techniques as well as implementation issues useful for designing modern high-performance power converters.

This paper proposes an Energy Management System for the optimal operation of Smart Grids and Microgrids, using Fully Connected Neuron Networks combined with Optimal Power Flow. An adaptive training algorithm based on Genetic Algorithms, Fuzzy Clustering and Neuron-by-Neuron Algorithms is used for generating new clusters and new neural networks. The proposed approach, integrating Demand Side Management and Active Management Schemes, allows significant enhancements in energy saving, customers' active participation in the open market and exploitation of renewable energy resources. The effectiveness of the proposed Energy Management System and adaptive training algorithm is verified on a 23-bus 11 kV microgrid.

The paper proposes a new fuzzy controller for variable speed wind turbines (WTs) in order to compensate the variations at the point of common coupling (PCC) by controlling the reactive power generated by WTs. A protection system is used to disconnect the WTs from the grid when the controller is unable to compensate the voltage variations. Simulations carried out on a real 37-bus Italian weak distribution network demonstrated that the controller allows compensating voltage variations during voltage sags.

For 100 years, there has been no change in the basic structure of the electrical power grid. Experiences have shown that the hierarchical, centrally controlled grid of the 20th Century is ill-suited to the needs of the 21st Century. To address the challenges of the existing power grid, the new concept of smart grid has emerged. The smart grid can be considered as a modern electric power grid infrastructure for enhanced efficiency and reliability through automated control, high-power converters, modern communications infrastructure, sensing and metering technologies, and modern energy management techniques based on the optimization of demand, energy and network availability, and so on. While current power systems are based on a solid information and communication infrastructure, the new smart grid needs a different and much more complex one, as its dimension is much larger. This paper addresses critical issues on smart grid technologies primarily in terms of information and communication technology (ICT) issues and opportunities. The main objective of this paper is to provide a contemporary look at the current state of the art in smart grid communications as well as to discuss the still-open research issues in this field. It is expected that this paper will provide a better understanding of the technologies, potential advantages and research challenges of the smart grid and provoke interest among the research community to further explore this promising research area.