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A novel single-stage LED driver for street lighting application is proposed in this article which combines a totem-pole boost PFC and a non-isolated LCCL resonant network. The converter offers several benefits, including: appropriate total harmonic distortion (THD) level and high power factor (PF) of the input current; reduced conduction losses and suppressed electromagnetic interference (EMI) thanks to its bridgeless structure; zero-voltage switching (ZVS) for the main switches and zero-current switching (ZCS) for rectifier diodes across the entire input voltage range and load conditions; a constant output current to an LED string load due to the LCCL network characteristic at the resonant frequency; and fixed-frequency operation via the main switches duty cycle for regulating the output current. The paper provides a detailed explanation of the proposed driver operating modes and theoretical analysis, as well as a comprehensive analysis of the impact of parameters on DC-link voltage level and main switches voltage stress. A design procedure is also presented. Experimental verification is demonstrated through a 100W prototype circuit operating at 200 kHz.

Switched capacitor multilevel inverter topologies are attractive among industrial power electronics researchers due to their applicability in sustainable energy systems such as renewable energy source (RES) applications. In this paper, a new switched capacitor (SC)-based grid-tied seven-level inverter is proposed for renewable energy sources (RES) applications. The proposed inverter can generate a seven-level output voltage waveform with voltage boosting ability and a gain factor of 3. Also, the proposed topology can provide the self voltage balancing for capacitors. The most important challenge of the SC-based topologies, i.e., the capacitor charging spike current, is solved by applying a soft charging circuit in the charging loop of the capacitors. The soft charging circuit consists of an inductor and a power diode in the capacitor charging path. Using a small size inductor in the soft charging circuit, the proposed inverter can limit the input current spikes. Comprehensive experiment results and comparisons are presented to verify the accurate performance of the proposed inverter.

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 ($N_{\mathrm{t}}$) 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.

Quasi-Z source (qZS) multilevel inverters have become popular in sustainable energy systems, particularly in photovoltaic (PV) systems. This study proposes a qZS five-level nested neutral point clamped (5L-NNPC) inverter, benefiting from continuous input current, high voltage gain, and insignificant voltage stress across semiconductors. The proposed topology provides a common ground between the input sources and the inverter's DC link, thus entirely eliminating leakage current, making it a suitable candidate for PV applications. Moreover, model predictive control (MPC) is employed to regulate the voltages of flying capacitors and the output current of the 5L-NNPC inverter. The study also includes analyses of steady-state performance, circuit design, efficiency, and control considerations. Finally, experimental results are presented to validate the converter's performance.

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.

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.

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.