The three-phase grid-connected inverters are widely employed in various distributed generation (DG) applications. The use of LCL filters at their outputs has proven several benefits, regarding passive component size reduction and improved high-frequency harmonics elimination. However, the resonance of the LCL filter hinders their application. Another issue with applying model predictive control (MPC) in LCL-filter-based DGs, as a high-performance controller, is the difficulty in including the various control objectives in a single cost function. The main issues include the necessity to compensate for various delays in the control loops and the selection of a proper weighting factor between objectives. Therefore, this paper proposes an efficient MPC method for grid-connected LCL-filtered DG inverters. The proposed MPC employs proper delay compensation for current/voltage loops. Furthermore, the proposed method incorporates various controlled variables in a single-objective function, eliminating the need for cascaded control loops. The proposed MPC is simulated in MATLAB/Simulink, and different test cases of active/reactive power demands are provided. The obtained results show the robust resonance-free performance of the proposed MPC method.

On-board integrated battery chargers (OIBCs) have gained considerable attention due to their low volume and weight, achieved by employing the traction drive converter as the on-board charging unit. This approach eliminates the need for additional hardware, such as extra semiconductor switches or passive filter components. In this paper, a novel OIBC based on the open-winding motor (OWM) drive is introduced. The proposed OIBC configuration is designed for single-phase power grids, making it particularly suitable for direct residential charging with household power without the need for additional conversion stages. The dual-inverter-fed OWM drive transforms into a power factor correction (PFC) converter and a two-phase interleaved buck converter during charging. Due to using the interleaved structure, the proposed OIBC supports fast-charging functionality, which reduces overall charging times. This paper applies the finite control-set model predictive control (FCS-MPC) along with a disturbance observer-based (DOB) method for the currents and voltages of both PFC and interleaved converters. This integration removes the need for a separate control board or a dedicated charging control algorithm. The validation of the proposed OIBC configuration and the MPC methodology is performed in MATLAB/Simulink software.

This paper presents a Continuous Control Set Model Predictive Control (CCS-MPC) enhanced with Nestorov Accelerated Gradient (NAG) for real-time closed-loop control of Cascaded H-Bridge (CHB) converters under normal operation and with faults on the power cells. The proposed method addresses limitations of conventional Finite Control Set MPC (FCS-MPC), including variable switching frequency and the computational burden for the control of multilevel converters. The main contributions of the proposed CCS-MPC with NAG are: (i) derivation of a dynamic model that enables simultaneous control of line currents and common-mode voltages under normal and fault conditions; (ii) formulation of the CCS-MPC problem as a convex, box-constrained optimization, enabling the use of an efficient projection-based solution within each NAG iteration to enforce feasibility; (iii) offline computation of matrices to minimize online computational burden; and (iv) a closed-loop reference voltage control to ensure fault-tolerant operation. The effectiveness of the proposed CCS-MPC with NAG is validated through real-time Hardware-in-the-Loop (HIL) simulations, that confirm the fast dynamic response and robust performance of the proposed algorithm under fault conditions and demonstrate its suitability for high-performance and reliable operation for industrial drives and grid-connected applications.

This paper proposes a simplified first-order nonlinear active disturbance rejection (SNADRC) controller for speed control of induction motor drives. The proposed technique eliminates the tracking differentiator component of the traditional NADR controller to cope with the complexity of the NADRC meanwhile leverage its advantages. The simulation results show the robustness of the proposed technique over the conventional proportional-Integral (PI)-based speed control against load disturbances. In addition, it show the superior dynamic performance achieved using the proposed technique compared to the first-order and second-order Linear ADR (LADR) controller.

Robust and efficient integration of photovoltaic (PV) sources is essential for enhancing the domination of renewable sources and promoting energy transition. Recently, impedance source inverters have attracted wide interest. However, they need a high number of passive components. Thence, lower efficiency, higher cost, and bulky volume are the main drawbacks of conventional impedance source inverters. The split source-based PV inverters (SSI) have presented lower components and smaller volume candidates in these applications. Therefore, this paper presents a modified dual-input-based SSI for PV inverters. Moreover, an improved finite control set (FCS) model predictive control (MPC) method is proposed for controlling the multi-inputted PV power with their expected shading conditions. The proposed FCS-MPC also injects high quality AC current/power to the utility grid side. The proposed dual input topology and FCS-MPC are verified experimentally. The superiority of input in addition to output sides waveform qualities has been proven.

This paper presents a hybrid controller based on fractional order control (FOC) with finite control set model predictive control (FCS-MPC) for LCL grid-tied single-phase multilevel inverters. Recently, FCS-MPC has received major interest in fast control tracking and handling several control objectives together in a single cost function. However, in the case of LCL grid-tied inverters, the control of the inverter side current, grid side current, and AC filter capacitor voltage, in addition to the voltage balance of dc-link capacitors, makes the design process of a single cost function more difficult to reach. Therefore, a cascaded FOC resonant controller for grid-side current with inner FCS-MPC for controlling inverter-side current and capacitor voltages is proposed for a single-phase five-level H-bridge T-type grid-tied inverter. The proposed controller merges the characteristics of FOC, FCS-MPC, and resonant controllers, improving system performance. Simulation results are provided to verify the superior tracking and control performance of the new proposed controller.

The availability of recently developed medium-voltage (MV) IGBT switch modules has made the diode-free alternative topology of three-level inverters a promising option, particularly for MV applications. Diode-free three-level-based solutions possess a smaller number of components and lower conduction losses in contrast to the diode-clamped NPC inverter. Nevertheless, some switches have to withstand half of the DC-link voltage, which still imposes restrictions on implementing a 3-level T-type inverter leg. This paper presents a reconfigured power circuit for a 3-level F-type inverter leg using a four-switch per phase-leg configuration. Compared to existing restrictions in T-type phase legs, the F-type phase leg reduces voltage stress, cost, and loss of the inverter. In this paper, an assessment is conducted to evaluate the performance and effectiveness of the F-type inverter. The investigation includes thermal analysis, switching loss, and efficiency analysis of the F-type inverter controlled by model predictive controllers. The results indicate that the F-type inverter acquires better loss distribution than the T-type inverter, revealing its usage in certain low-voltage and medium-voltage applications.

This article presents an optimization in implementing a DTC control scheme using a 3L-NPC inverter to control the speed of a three-phase induction machine. Regarding the DTC strategy, 3 and 5-level hysteresis controllers were used to control the stator flux and electromagnetic torque, respectively. The traditional implementation of the scheme [2], shows good results regarding the motor speed response; however, the electromagnetic torque developed by the motor presents various issues: significant ripples in torque produced by a poor choice of the hysteresis controller amplitude, poor tracking of the torque reference signal in steady state, and high torque peaks in large speed steps, which translate into current peaks that exceed the motor’s thermal limit. This work proposes new strategies for adjusting the flux and electric torque hysteresis controllers, which will correct the problems presented in the traditional implementation. Finally, a comparison will be made between the modified DTC strategy and the traditional DTC strategy of [2].

Recently, doubly grounded (DG) photovoltaic (PV) inverters have proven superior performance in total elimination capability of PV leakage currents. This is due to the direct connection of PV side negative terminal with grid side neutral terminal. This paper presents a boost DG-PV five-level (5L) inverter topology based on neutral point clamped (NPC) leg. The proposed DG-PV boost 5L-NPC inverter totally eliminates the existing leakage currents, achieves boost of PV voltage, is considered a single stage PV inverter structure, uses low component count, and has continuous PV current. Moreover, finite control set model predictive control (FCS-MPC) is presented for controlling multiple objectives in a single cost function for the proposed topology. The FCS-MPC also eliminates the cascaded l0ops in the conventional control methods, which facilitates the control design process. A simulation based case study is preformed of the proposed DG-PV boost 5L-NPC inverter with FCS-MPC controller. Superiority of proposed inverter and controller have been verified with various step changes in PV power, power quality of injected grid current, and capacitor voltage control.

The rapid growth of smart grids necessitates advanced control strategies to ensure efficient and reliable power distribution. This paper proposes a hierarchical control framework based on Model Predictive Control (MPC) for managing power distribution in a smart grid. The hierarchical structure comprises three control levels: the first hierarchy is to control the inverter variables and the LC filter voltage, the second hierarchy supervises the power control restriction for every inverter, and the hierarchy is for power coordination, which utilizes long-term condition and prediction and power supply restriction (solar or wind capability, among other conditions or restrictions). The simulation results presented in this paper validate the fast control response and the capability of coordination between the different hierarchies of the proposed strategy.

This paper presents a novel hierarchical control scheme based on Model Predictive Control (MPC) for a Voltage Source Inverter (VSI) operating under conditions of unbalanced and nonlinear loads. The increasing prevalence of renewable energy sources and the proliferation of power electronic devices has led to a growing need for robust control strategies that can effectively handle the challenges associated with unbalanced and nonlinear loads in power distribution systems. In this work, a two-hierarchy control structure is proposed, based on a full MPC strategy. The MPC controller in the first hierarchy is responsible for optimizing the VSI's switching states in real-time, taking into account the system's constraints and the desired performance criteria of the output voltage of the VSI. The MPC controller in the second hierarchy regulates the output current of the VSI to track the reference values for the load and grid power. The proposed control scheme addresses the challenges posed by unbalanced and nonlinear loads, the simulation results demonstrate the effectiveness of the proposed hierarchical control strategy in mitigating voltage deviations, minimizing harmonic distortions, and ensuring balanced operation in the presence of unbalanced and nonlinear loads. The presented approach offers a promising solution for enhancing the performance and stability of VSI-based power distribution systems, thus contributing to the overall reliability and efficiency of modern electrical grids.

Analysis and performance of a three-phase single-stage SEPIC differential-mode inverter (DMI) using a discontinuous modulation scheme (DMS) are presented in this paper. Since the DMS was previously suggested in many inverter topologies to reduce the voltage stress of utilized switching devices and enhance inverter efficiency, a simple design process to integrate DMS into the SEPIC DMI is proposed in this work. With this modulation strategy, the discontinuity of the duty cycle for one-third of the entire grid frequency cycle thoroughly minimizes the conduction losses and switching losses into the SEPIC converters. Also, it is noted that the voltage stress is significantly reduced in passive elements as well as switching devices. Furthermore, the compensation of the negative sequence harmonic components is maintained without adding extra sensors. The inverter operation along with mathematical analysis of the DMS and grid current control is presented. A PSIM simulator is used to evaluate the behavior of the proposed modulation strategy. Finally, a comparison with the conventional continuous modulation scheme (CMS) is performed for a better assessment.

This paper proposes a Master-Slave Model Predictive Control for parallel grid-tied inverters in a microgrid. In this configuration, the Master is a grid-forming inverter with a Battery Energy Storage System as dc input, while the Slave is a grid-following PV inverter that provides the power to the load. First, the inverter models are derived and then their MPC controllers are presented in details. Finally, Hardware-in-the-Loop results are presented for different operational conditions for the microgrid, including grid connection, islanded mode and load variations. The results demonstrate the advantages of the proposed MPC such as faster dynamic response, multi variable control, adequate load sharing between the inverters, robustness to parametric uncertainties and variations and the possibility to directly include system constrains and non-linearities in the controller implementation.

This paper presents an improved sequential model predictive control (MPC) method for single phase photovoltaic (PV) applications. The T-type H-bridge five-level topology is selected in this paper. The proposed method achieves constant switching frequency operation of the inverter, which is advantageous over the variable switching frequency MPC methods. The proposed fixed switching frequency MPC (FSF-MPC) method eliminates the weighting factors, which represent critical element in applying classical MPC methods. Moreover, the proposed FSF-MPC method achieves low dv/dt values through using optimized switching sequences to evaluate the cost function. The simulation results of the proposed FSF-MPC method are provided and compared with variable switching frequency MPC method. The results show the fast tracking in both controllers. Whereas, fixed switching frequency and weighting factorless operation are obtained using the proposed FSF-MPC method. Additionally, lower total harmonic distortion (THD) in the output voltage is obtained using the proposed FSF-MPC method compared to classical MPC method.

Battery energy storage systems (BESSs) have be-come integral parts in photovoltaic (PV) energy systems due to their fluctuated nature. The most common solutions in the literature for hybrid PV-battery systems are based on two-stage power converter solutions with separate power converters. However, these solutions increase the cost of the system and the number of required devices. Additionally, leakage currents represent critical issue for safe and reliable operation of PV systems. This paper presents a three-port configuration for hybrid PV-battery grid-connected systems. The proposed configuration includes a common ground connection between the PV side and grid side, which results in the elimination of leakage current components. Moreover, a finite control set model predictive control (FCS-MPC) is presented in this paper for controlling the proposed three-port configuration. The proposed controller achieves the control of multiple objectives simultaneously in addition to having fast dynamic response. Simulation results of the proposed configuration and control method are provided in this paper. The results show the effectiveness of the proposed configuration for hybrid PV-battery systems.

This paper presents a new common grounded (CG) multilevel boost inverter (MI) topology for single-phase grid-tied photovoltaic (PV) applications. The proposed topology has the capability to fully eliminate the leakage currents in PV systems due to the using of the CG connection. Additionally, the proposed topology benefits the high boosting factor capability of the low PV voltage. The proposed topology represents a single stage power conversion system with reduced power components compared to the traditional two-stage PV power conversion systems. In addition, model predictive controller (MPC) is proposed in this paper to control the proposed topology. The proposed controller can control multiple objectives simultaneously without using cascaded controllers. The simulation results with the different case studies are provided. The results confirm the superiority of the proposed CG boost MI topology and the proposed MPC method. Furthermore, fast tracking of the grid active and reactive power demands is achieved using the proposed MPC method.

In this paper, a space Vector modulation scheme (SVMS) to enhance the performance of the single-stage three-phase grid-tied SEPIC-based differential inverter is presented. Compared to the traditional modulation schemes, the proposed modulation scheme offers a significant reduction in the peaks of output voltages and input currents of the utilized SEPIC modules at the same voltage gain. Moreover, the peak voltages of the utilized capacitors in SEPIC converters are reduced. Therefore, the voltage stresses, conduction losses, and switching losses have been decreased, and the system efficiency has been increased in accordance. The proposed SVMS is implemented by employing a simple modification to the traditional continuous modulation scheme (CMS) of differential inverters, which keeps the smooth operation of the grid-current control at the inverter side and verifies low execution time. Moreover, a detailed comparison between the proposed modulation scheme and traditional CMS at different power ratings is introduced. The performance of the proposed SVMS is evaluated using the PSIM environment to validate the theoretical features added to the grid-current control and the SEPIC-based differential inverter.

Transformerless photovoltaic (PV) inverter topologies have proven superior performance over transformer-based inverter topologies. However, they face challenges due to their high leakage currents and voltage step-up requirements. There-fore, modified topologies and/or modulation techniques are essential to limit the current leakages to standard limits. The doubly grounded (DG) inverter topologies represent efficient solutions for totally limiting the leakage currents. This paper presents a finite control set (FCS) model predictive controller (MPC) method for DG step-up five-level PV inverter topology. The proposed FCS-MPC method can control the injected grid currents and multiple capacitors voltages simultaneously with high power quality output. The modelling and design of the step-up inverter topology and the FCS-MPC method are given in the paper. Simulation results with step-up DG five-level PV inverter topology are performed to validate the proposed FCS-MPC method. Moreover, the proposed FCS-MPC method has been validated using simulation results at the various operating conditions of PV inverters.

Leakage currents represent critical issues for the operation of conventional photovoltaic (PV) inverter topologies. Recently, the common grounded (CG) PV inverter topologies have presented superior performance over the conventional PV inverter topologies from the leakage currents elimination point of view. The multilevel CG-PV inverter topologies combine both features of the multilevel output voltage and the CG connection. Among the existing CG topologies, the switched capacitor types have found wide applications due to the lower cost, volume, and losses on the passive inductors. However, burdens have been risen for the control system to achieve multi-objectives, which includes controlling the output current of the inverter and the capacitor voltages. Therefore, this paper presents a Finite Control Set Model Predictive Control (FCS-MPC) method for five-level CG single-phase PV inverter topology. The FCS-MPC method presents reduced harmonic contents of the output currents and precise tracking to its reference value. The design guidelines of the FCS-MPC method and weighting factor adjustments are provided in this paper. Simulation results are presented in order to validate the effectiveness of the FCS-MPC method.

Fault tolerant (FT) operation in photovoltaic (PV) inverters is gaining increased attention in order to improve system availability. Conventional string PV inverters lack the ability to eliminate the leakage currents of the system during fault modes of operation. Therefore, traditional PV inverters are modified through modulations and structures to tolerate such faults. However, proper operation and control of FT-PV-inverters remain challenging, particularly on the better utilization of the extra added components. This paper proposes a new modulation method for eliminating the PV inverter leakage current in normal and faulty modes of operations. The sinusoidal based pulse width modulation (PWM) scheme is modified for implementing the new proposed modulation. In addition, the proposed PWM is capable of preserving full rating and energy efficiency operation of the inverter with leakage current elimination in both the normal and faulty operating modes. The proposed inverter and modulation method are implemented and tested at various conditions. The results confirm the superiority and leakage current elimination capability of the new proposed PWM method.

Boosting lifetime of power components in multilevel inverters is a major aim to enhance the total system reliability and performance. This paper presents a space vector pulse width modulation (SVPWM) strategy for lifetime prolongation of thermally-overloaded power devices in multilevel inverters. When a thermal overloading is detected in one of the power devices, the proposed algorithm is applied to relieve the overloaded device and therefore preventing dangerous circumstances such as open-or short-circuit faults. The proposed methodology relies on using the redundancy property between the switching states in multilevel inverters to continuously evaluate the junction temperature of the thermally-overloaded power devices for all the possible switching sequences, then it identifies the optimal relieving switching sequence. The proposed methodology is valid for both/either of the power switching devices and/or DC-link capacitors. The proposed strategy is simple, and does not require any additional hardware. Furthermore, it does not deteriorate the output power. Accordingly, lifetime and reliability of multilevel inverters have been enhanced considerably. The proposed methodology has been designed and validated by simulation and experimental prototyping of a three-level T-type inverter system to investigate its feasibility and effectiveness.