This article presents a detailed procedure for deriving the generalized average model (GAM) of a dual active bridge converter. The proposed model incorporates higher orders of harmonic components to increase accuracy. Moreover, the turn ratio of the high-frequency transformer (N_t) is considered for realistic modeling, which removes the conventional assumption of unity turn ratio. A detailed model of the DAB will ensure an accurate control design. Required mathematical expressions are derived and explained thoroughly, with an example showcasing a GAM model of the DAB converter up to the ninth harmonics. Several GAM models using different harmonic orders (first, third, fifth, seventh, and ninth harmonics) are derived and compared to the PLECS simulation model and a real-time simulation of the DAB converter on the PLECS RT-Box-2. Results show that including up to the ninth harmonics in the proposed model of the DAB converter leads to achieving accurate voltage and current amplitudes that are almost identical to the simulation outputs and even better than the experimental results.

This article presents a new high step-up quasi-Z-source-based dc-dc converter with switched boost techniques and voltage multiplier cells. Compared with the conventional Z-source-based converters, this converter not only can achieve high voltage gain but also has good efficiency at high output voltage and higher output power conditions. Most of the Z-source-based converters suffer from high current stress across the power mosfets and the operation in lower power. However, the other important advantages include very low input current ripple, low voltage and current stress across the power switches, no duty ratio limitation, and leakage current elimination by providing the common grounded feature. So, in this topology, the null of the output is connected to the negative terminal of the input dc source directly. Therefore, the leakage current can be eliminated completely. As a result, the proposed converter is suitable for renewable energy sources (RESs)' applications, such as photovoltaic (PV) systems. The mathematical analysis, operating principle for the proposed converter, and comparison with other converters are evaluated. Finally, in order to verify the accurate performance of the proposed converter and confirm the mentioned features of the proposed converter, a 1-kW laboratory prototype is built and tested.

Multilevel converters (MLCs) are widely recognized for their exceptional benefits and have emerged as the preferred choice for medium- and high-power/voltage applications. Their usage has also been extended to low-power applications to overcome issues associated with high switching frequencies and electromagnetic interference (EMI) commonly encountered in two-level converters. Common dc-link MLCs have received particular attention in industry due to their ability to eliminate the need for bulky and inefficient transformers and rectifiers, making them a compelling option for different applications, primarily medium- and high-power/voltage applications such as wind turbine (WT) power conversion systems. Furthermore, common dc-link topologies are required for back-to-back (BTB) configurations, as they facilitate the use of a shared dc-link between the rectification and inversion stages. Despite their popularity, there is currently no comprehensive review article dedicated to common dc-link topologies. This article addresses this gap by presenting a comprehensive review of common dc-link MLCs, covering their topological evolution, features, topologies comparison, modulation techniques, control strategies, and industrial application areas. Additionally, future perspectives and recommendations are discussed to provide researchers and engineers with a better understanding of the potential applications and advantages of these converters.

This paper proposes an auto-tuned finite control set-model predictive control (FCS-MPC) for a grid-tied singlephase crossover switches cell (CSC) inverter. The multilevel inverter (MLI) under study generates 9 voltage levels. The FCSMPCobjective is to minimize the total harmonic distortion (THD) of the current fed to the grid with unity power factor while regulating the capacitor voltage at its reference value to maintain the 9 voltage levels. The switching losses are reduced by managing the redundant switching states selection. Artificial Neural Network (ANN) based on the Bayesian regularized feedforward learning technique is applied to predict the optimal weighting factor of the FCS-MPC with respect to the measured reference current value. The effect of using a dynamic weighting factor on the current THD for different reference current peak values (ranging from 2A to 8A) is studied through MATLAB/Simulink simulation. The presented simulation is intended to show that the application of a dynamic weighting factor can significantly enhance the current THD compared to the use of a fixed weighting factor.

Multilevel inverters (MLIs) are widely employed in high power and high voltage applications due to their advantages like better power quality and lower voltage stress across power switches compared to the traditional two-level inverter. However, the utilization of higher number of power semiconductor devices and capacitors results in less reliability. In this regard, a fault-tolerant MLI (FTMLI) with asymmetrical source configuration is developed which can tolerate the open-circuit and short-circuit switch failures (single and multiple switch faults). The proposed topology preserves the output power and balances the capacitor's voltage under pre and postfault conditions. Further, a new switching scheme is proposed to reduce the ripple content in the capacitor's voltage. Further, under postfault operation uses less number of conducting switches resulting in a better efficiency. The proposed FTMLI generates a higher number of voltage levels with less number of component counts when compared with recently proposed topologies. Moreover, this comparative study reveals the prevalence of the proposed converter in the recent literature. The conducted experimental test proves the effectiveness and fault-tolerant feature of the proposed topology.

The battery charging power electronics interface of an electric vehicle (EV) must be capable of bidirectional power flow to enable both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operations. In the presence of a single/three-phase AC supply, the front-end of the EV charger employs a power factor correction (PFC) rectifier, which should have the bidirectional capability to facilitate V2G mode. A conventional active rectifier functions in boost mode while performing PFC and voltage regulation. In most of the currently available EVs, however, the battery nominal voltage is low and, hence, a downstream high step-down DC-DC converter and high voltage DC bus capacitor are required in the charging interface. To overcome these issues, this work proposes a bidirectional AC-to-DC buck rectifier topology that can operate in G2V and V2G modes, both in single-and three-phase versions. The proposed topology utilizes the switched capacitors principle to achieve self-balancing of voltages in the capacitors. In addition, it is highly modular in structure. This paper describes the proposed topology, its working and modulation and its applications. The hardware proto model is used to validate the proposed power converter and the control approach to achieve PFC and voltage regulation. In addition, a comparison with other topologies is presented to demonstrate its competence.

Nowadays, single-dc-source multilevel inverter (SDCS-MLI) topologies are being considered as more suitable for many power system applications such as renewable energy conversion systems and electrified transportations compared to the multiple-dc-source MLIs. Voltage balancing of the auxiliary capacitors in those configurations is a major matter of concern. Different techniques have been developed to overcome this issue that can be mainly categorized as internal controller-based and external controller-based techniques. In the former techniques, the redundant switching states help balancing the capacitors voltages. On the other hand, the latter techniques involve external regulators to balance the capacitors' voltages. This article analyzes most of the existing techniques to control and balance the capacitors voltages in SDCS-MLIs, such as pulsewidth modulation, space vector modulation (SVM), hysteresis control, model predictive control, sliding mode, and artificial intelligence based control techniques. Furthermore, a comprehensive comparison is presented to illustrate the advantages/disadvantages of each technique. Finally, some industrial challenges and future works are projected.

In this paper, an optimized auto-tuning of Finite Control Set-Model Predictive Control (FCS-MPC) is proposed for a 9-level Crossover Switches Cell (CSC9) inverter. The system under study, a grid-connected single-phase CSC9 inverter-based PV system, is designed to extract maximum power from the PV panels and feed it to the grid with unity power factor and low current total harmonic distortion (THD). These objectives are achieved while regulating the CSC capacitor's voltage at its reference value to maintain the 9 voltage levels at the inverter output terminals. In the cost function design, the minimization of the switching transitions along with the errors on the capacitor voltage and grid current (consequently current THD) were selected as control objectives, where the higher priority was given to the latter. The objective of reducing the switching events is assumed to have the least priority while the weighting factor on the capacitor voltage is dynamic and its value is determined by a pre-defined polynomial. Moreover, the optimization of the cost function is performed over two-step prediction horizon. The performance of the proposed control design (current THD enhancement and switching transitions reduction) is compared in simulation with the fixed weighting factor and one-step horizon without switching transitions constraint FCS-MPC case scenario.

A critical advancement in solar photovoltaic (PV) establishment has led to robust acceleration towards the evolution of new MPPT techniques. The sun-oriented PV framework has a non-linear characteristic in varying climatic conditions, which considerably impact the PV framework yield. Furthermore, the partial shading condition (PSC) causes major problems, such as a drop in the output power yield and multiple peaks in the P–V attribute. Hence, following the global maximum power point (GMPP) under PSC is a demanding problem. Subsequently, different maximum power point tracking (MPPT) strategies have been utilized to improve the yield of a PV framework. However, the disarray lies in choosing the best MPPT technique from the wide algorithms for a particular purpose. Each algorithm has its benefits and drawbacks. Hence, there is a fundamental need for an appropriate audit of the MPPT strategies from time to time. This article presents new works done in the global power point tracking (GMPPT) algorithm field under the PSCs. It sums up different MPPT strategies alongside their working principle, mathematical representation, and flow charts. Moreover, tables depicted in this study briefly organize the significant attributes of algorithms. This work will serve as a reference for sorting an MPPT technique while designing PV systems.

This paper used an artificial jellyfish search (AJFS) optimizer suitable for selective harmonic elimination-based modulation for multilevel inverter (MLI) voltage control application. The main objective was to remove the undesired lower-order harmonics in the output voltage waveform of an MLI. This algorithm was motivated by the behavior of jellyfish in the ocean. Jellyfish have the ability to find the global best position where a large quantity of nutritious food is available. The paper applied AJFS algorithm on five, seven, and nine levels of CHB-MLI. The optimum switching angle was calculated for the entire modulation range for the desired lower-order harmonics elimi-nation. The problem formulated to achieve the objective was solved in a MATLAB environment. The total harmonic distortion (THD) values of five-, seven-, and nine-level inverters for various modulation indexes were computed using AJFS and compared with the powerful differential evolution (DE) algorithm. The comparison of THD results clearly demonstrated superior THD in the output of CHB-MLI of the AJFS algorithm over DE and GA algorithm for low and medium values of modulation index. The experimental results further validated the better performance of the AJFS algorithm.

Having a reduced number of switches and isolated DC sources yet generating a higher number of voltage levels has been always the challenge when selecting the appropriate Multilevel Inverter (MLI) topology. Nowadays, Single-DC-Source Multilevel Inverter (SDCS-MLI) topologies are being considered as more suitable for many power system applications such as Renewable Energy (RE) conversion systems and electrified transportations compared to the Multiple-DC-Source MLIs (MDCS-MLIs). Moreover, increasing the power rating and minimizing the switching frequency while maintaining reasonable power quality using a SDCS-MLI is an important requirement and a persistent challenge for the industry. Thus, this paper presents a general review on the available SDCS-MLI topologies and future trends. Existing solutions are discussed and analyzed based on their topologies, number of output voltage levels, number of active/passive components, advantages/limitations, maturity, and industrial applications. Furthermore, recommendations for future research and development are suggested in this paper.

An extensive use of electric vehicles (EVs) is evolving as an important solution to counter environmental pollution, rapid exhaustion of fossil fuels and insecurity caused by fluctuations in the price of petroleum products in the international market. The integration of EVs to the grid is required for the future enhancement of the transportation system. Grid integration of EVs also presents an interesting opportunity to solve the issues faced due to intermittent nature of renewable energy sources (RES) connected to the grid. The charging of EVs must be well coordinated with the grid otherwise it will result into an uncertain large electric load, causing peak-load and grid issues. Thus, the EV technology presents opportunities as well as challenges to the electricity grid. The development in EV technologies, battery systems, and different charging methodologies are reviewed with special focus on vehicle to grid technology as a solution to many grid issues, especially with RES connected to it. This paper presents a brief overview of these issues and various solutions.

The Crossover Switches Cell (CSC) is a recent Single DC-Source Multilevel Inverter (SDCS-MLI) topology with boosting abilities. In grid-connected PV applications, the CSC should be controlled to inject a sinusoidal current to the grid with low THD% and unity power factor, while balancing the capacitor voltage around its reference. These two objectives can be met through the application of a finite control set model predictive control (FCS-MPC) method. Thus, this paper proposes a design of an optimized FCS-MPC for a 9-level grid-tied CSC inverter. The switching actions are optimized using the redundant switching states. The design is verified through simulations and real-time implementation. The presented results show that the THD% of the grid current is 1.73%, and the capacitor voltage is maintained around its reference with less than 0.5 V mean error. To test the reliability of the control design, different scenarios were applied, including variations in the control reference values as well as the AC grid voltage. The presented results prove the good performance of the designed controller in tracking the reference values and minimizing the steady-state errors.