With the increasing dc-bus voltage level and power rating in renewable-energy applications, dual-parallel five-level active neutral-point-clamped (5L-ANPC) inverters have attracted growing attention because they can increase system capacity and improve output current quality. However, under asynchronous strategy, the dual-parallel 5L-ANPC inverters face a large number of space voltage vectors. Meanwhile, the simultaneous requirements of current tracking, CMV reduction, circulating current suppression, and capacitor voltage balancing further increase the difficulty of multi-objective control. To address these issues, this paper proposes a three-layer simplified model predictive control (MPC) strategy. The dual-parallel system is regarded as an equivalent nine-level inverter to improve the output current quality. To avoid the heavy burden caused by the large space voltage vector diagram, the gh coordinate system is adopted to calculate the required vector coordinates online, and low-CMV vector states are further selected to synthesize the reference voltage ( $V_{ref}$ ) without lookup tables (LUT). Then, a dynamic circulating current control strategy is developed to reallocate the vector states of each 5L-ANPC inverter, so that differential-mode current (DMCC) and zero-sequence circulating current (ZSCC) can be suppressed even under conditions of severe inductance mismatch. Finally, redundant switching combinations are used to balance the floating capacitor voltage (FCV) and neutral-point voltage (NPV). Experimental results show that compared with the advanced synchronous MPC strategy, the proposed strategy reduces the CMV peak-to-peak value by half, decreases the CMV RMS by up to 50%, and lowers the output current THD by at least 25%.
This paper presents a power control strategy for a grid-connected three-level neutral-point-clamped inverter. The proposed approach integrates Model Predictive Control (MPC) with a modified Space Vector Modulation (SVM) scheme. The control structure comprises an inner current control loop and an outer DC-link voltage control loop to regulate both active and reactive power. To address the neutral-point voltage imbalance issue, a modified SVM method is developed by adaptively adjusting the dwell times of voltage vectors. This approach effectively balances the capacitor voltages, mitigates voltage fluctuations, and reduces current harmonic distortion. Simulation results in Matlab/Simulink verify that the active and reactive powers accurately track their reference values, achieving minimal steady-state error and fast dynamic response. In addition, the DC-link voltage remains stable, and the capacitor voltages are well balanced even under the application of medium voltage vectors. Furthermore, compared with the conventional finite control set MPC (FCS-MPC), the proposed method achieves superior performance in terms of lower total harmonic distortion of the grid current, owing to its fixed switching frequency, as well as reduced neutral-point voltage ripple.
Quang Huy Nguyen, A. T. Nguyen, Van Vi Nguyen et al.· E3S Web of Conferences· 0 citations
As renewable energy becomes increasingly essential to global energy strategies, grid-connected photovoltaic (PV) systems are gaining prominence. However, these systems introduce challenges related to power quality and system stability. This paper presents a unified nonlinear cascaded control strategy tailored for a multilevel single-input dual-output (SIDO) boost converter-based grid-connected PV system. The proposed approach is aimed at integrating the sliding mode control (SMC) for both maximum power point tracking (MPPT) and power factor correction (PFC) tasks, while a filtered proportional-integral (PI) controller is employed to stabilize DC voltage regulation. This combination control framework ensures these objectives under varying environmental conditions, all while taking advantage of multilevel conversion, such as reduced component stress and high voltage gain without transformers. Simulations studied within the MATLAB/Simulink environment confirm the proposed approach effectiveness, demonstrating reliable performance and enhanced improvements in system stability compared with the widely conventional approach.
Ouijdane Arich, A. Abouloifa, Amine El Boudali et al.· EPJ Web of Conferences· 0 citations
This study proposes a cascaded power conversion structure composed of a three-level DC-DC boost converter and a single-phase five-level T-type inverter to address the high performance and power quality demands of renewable energy systems. The integrated topology is designed to overcome the limitations of conventional two-level architectures by combining high voltage gain with reduced voltage stress on power switches and minimized total harmonic distortion (THD). The paper presents a comprehensive mathematical model and a robust control strategy, utilizing decoupled loops for total DC-link voltage regulation and neutral-point balancing, alongside a synchronous reference frame current controller for the inverter stage. Simulation studies conducted in the MATLAB/Simulink environment validate the operational characteristics of the proposed system. The results demonstrate that the boost stage maintains a stable symmetric DC-link voltage of 350Vdc (∓175Vdc). Furthermore, the T-type inverter generates a five-level output waveform with a THD as low as 1.22% under steady-state conditions and 1.01% under dynamic loading, compliant with IEEE 519 standards. This confirms the system capability to reduce voltage stress on switches by 50% while ensuring high-quality power delivery.
Unknown authors· Gazi Üniversitesi Fen Biliml...· 0 citations
The high rate of replacement of synchronous machines by inverter-based resources (IBRs) has increased the role of Dynamic Voltage Support (DVS) during grid disturbances, especially on weak and failed grid conditions. Traditional reactive-current-based grid-support rules can have a poor performance with large R/X ratios, deep voltage sags, and hard inverter current or power constraints. To this end, much research has been done on the development of the best control measures that can help in maximizing positive- sequence voltage, improving low-voltage ride-through capability, and reducing synchronization instability. The review gives a cohesive and thorough evaluation of the best DVS strategies, including analytical global-optimality models, model-driven optimization, sensitivity-based methods, active/reactive power allocation models, and newly developed model-free and real-time optimum-seeking controllers. The review identifies the importance of current limits, active power availability, and synchronization stability limitations in determining inverter behavior, and contrasts the outputs of various approaches to these problems in the presence of varying grid strengths. Aspects in practical implementation of photovoltaic, wind and storage inverters are discussed and also robustness in the face of parameter uncertainties. Future directions in research (such as adaptive optimization, controllers based on learning, multi-inverter coordination, and grid-forming DVS) are determined. This review summarizes the latest knowledge and defines the directions of resilient, optimal, and grid-code-conforming voltage support of next- generation power electronic inverters.
Prashant Kumar, Y. Singh· 2026 International Conferenc...· 0 citations
Based on the traditional Single-Phase-Shift (SPS) modulation, the control method of Dual Active Bridge (DAB) converter is improved in this paper. By introducing the cross-conduction constraint mechanism in the secondary bridge arm, the overlapping conduction region of the switch is effectively limited, and the three-level voltage output is realized without introducing additional complex control strategies. The proposed method can significantly weaken the reverse component of the secondary current, thereby reducing the invalid circulating energy in the system. The simulation results show that the negative peak current decreases from − 54.7 A to − 9.7 A, indicating that the current waveform has been significantly optimized. In addition, the realization of zero-voltage switching (ZVS) is verified by simulation analysis. There is a measurable zero voltage interval before the device is powered on, which indicates that the soft switch is reliable. The reduction of circulating current and the enhancement of switching characteristics indicate the potential for performance improvement. This method provides a simple and effective solution for improving the current characteristics and switching conditions of high frequency DAB converter.