Simone Cosso

In this paper a modulation strategy for an AC-DC isolated Matrix Charger three-phase rectifier(MCharger) is proposed. The proposed topology enables precise current and voltage regulation, and itcan be therefore employed in energy storage applications, such as Electric Vehicles (EVs) batteries. Incontrast to the conventional Dual-Active-Bridge (DAB) architecture, the Matrix converter facilitatesdirect AC-to-AC power conversion, thereby removing the need for an intermediate rectificationstage. It produces a high-frequency AC voltage that directly supplies the isolation transformer. Thistransformer typically exhibits very low leakage inductance, which helps minimize voltage drops acrossit. At the output, an H-bridge followed by an LC filter performs the rectification of the high-frequencyAC signal. The proposed structure has been compared with a conventional solution implementing anactive front end and a DAB and the simulation results are presented. In addition, the developed controlapproach has been implemented in a laboratory setup and it has been validated through experimentalresults on a converter prototype.

Fuel cell electric vehicles (FCEVs) rely on a battery system to manage transient load demands and to recover braking energy. In recent years, hybrid topologies that also integrate supercapacitors have gained considerable attention, since they can improve system efficiency, driving dynamics, and component lifetime. Supercapacitors, thanks to their much higher power density compared to conventional batteries, are particularly promising for adoption in FCEVs. Most studies in the literature, however, evaluate these architectures under standardized homologation driving cycles. While such cycles provide a common benchmark for comparison, they generally exhibit less energy-intensive profiles and therefore do not fully capture the real operating demands of a vehicle. For this reason, the present work investigates the use of batteries and supercapacitors in FCEVs under an actual urban driving mission, where the route includes an experimentally measured altitude profile. This approach allows for a more realistic assessment of energy requirements. Furthermore, the analysis carried out in this study considers different powertrain configurations: the exclusive use of a battery, the sole use of a supercapacitor, and a hybrid combination of both systems. These scenarios are evaluated both for an FCEV that can only be refueled with hydrogen and for a plug-in hybrid version of the vehicle that can also recharge its battery from an external charging station.

Low-voltage power converters in the 25–200 V range are increasingly employed in emerging applications such as hybrid electric vehicles (HEVs), photovoltaic systems with battery storage, and electric propulsion systems for recreational boats. In these contexts, 48 V battery systems have become standard, due to safety considerations. Among various converter topologies, H-bridge configurations operating around 100 V DC are widely used in laboratory-scale prototyping. While MOSFETs are the preferred switching devices in this voltage range, due to their high efficiency and fast switching characteristics, they also introduce design challenges related to high current slew rates and associated overvoltage spikes caused by parasitic inductances in the PCB layout. These overvoltages, though modest in absolute terms, can be critical in low-voltage systems, due to the lower device ratings. This paper presents design strategies and layout best practice for a 120 V, 50 A H-bridge converter using 200 V rated MOSFETs. The effectiveness of various mitigation techniques—including the use of ceramic capacitors in parallel with film and electrolytic types, Schottky diodes across MOSFETs, and snubber circuits—is evaluated and experimentally validated on a dedicated prototype. The results highlight the critical role of PCB design in ensuring switching reliability and device protection in low-voltage converter systems. In addition, with the design solutions shown in this study, it was possible to obtain a voltage overshoot during switching of just 165 V with a 120 V DC-link voltage, which guarantees a sufficient safety margin for the MOSFET rated voltage.

In medium-voltage AC applications, multilevel converters are essential due to their ability to achieve high efficiency and significantly reduce total harmonic distortion (THD), ensuring improved performance and power quality. This paper presents a detailed analysis of the efficiency, power loss, and THD characteristics of multiplexed multilevel converters and neutral point clamped converters. Using MATLAB^®Simulink 2024b, the switching and conduction losses of both multiplexed multilevel converters and NPC converters are calculated. The three-level NPC converter offers advantages of a simpler design, reduced component count, and cost effectiveness with the drawback of low voltage quality. Simulation results validate the THD, power losses, and efficiency for the conventional three-phase three-level NPC converter and the three-phase multiplexed multilevel converter, and a detailed comparison is performed.

In contemporary power electronics, multilevel converters stand at the forefront of high-power, high-voltage applications, offering superior performance in terms of efficiency, reduced harmonics, and improved voltage waveform quality compared to traditional two-level converters. Their capability to synthesize waveforms with multiple voltage levels has garnered significant attention across various industrial sectors, including renewable energy systems, electric vehicles, and high-voltage power transmissions. This paper provides a comprehensive overview of multilevel converter technology, encompassing their classification, main topologies, recent advancements, and emerging trends. By exploring the evolution of multilevel converter technology and identifying future research directions, researchers and engineers can gain valuable insights into the design, optimization, and application of these advanced power electronic systems.

A new topology of multi-input bidirectional DC-DC converters is proposed in this paper. The converter has a boost behavior, i.e., the output voltage is higher than the sum of the input voltages. This family of converters is particularly suited for hybrid energy storage systems, where different DC sources are connected together and where the output voltage is significantly higher than the voltage of a single storage. The proposed converter reduces the number of required switches, leading to higher efficiency and reduced complexity compared to traditional n-input converters. The new topology demonstrates superior performance by enabling higher efficiency with fewer components. A dedicated control, based on PI controllers, is provided to ensure stable operation under dynamic conditions. The effectiveness of the proposed solution is tested using experimental results on a four-input 20 A/100 V converter prototype.

In this study, a double-input single-output bidirectional DC–DC converter is considered. This particular architecture allows less switches to be used than a conventional solution. A new feed-forward current control for this DC–DC converter with three switches is presented in this paper. The modulation technique proposed in the literature for the aforementioned converter leads to a consistent loss reduction at low load, exploiting the DCM. As a drawback, when using this control strategy, the dynamic response worsens significantly. To speed up the control, a feed-forward approach is designed and implemented using a simplified converter electrical model. The proposed strategy is compared with the conventional PI controller, and it is validated and verified through simulation results in the MATLAB/Simulink/PLECS environment and through experimental tests using a converter prototype.

In this article, a V/f control for high-power induction motor drives is analysed. In such uses, low dynamics in terms of speed-loop bandwidth is usually required. However, in some applications, where the load consists of a long shaft with certain mechanical components and with some resonant frequencies, instability and torque oscillations can cause significant damage. For these reasons, open-loop V/f control could be a winning solution, since it avoids resonances and oscillations caused by measurement feedbacks in the control. However, instability may arise also in open-loop V/f control. A stability analysis is here carried out analytically and a new method to overcome oscillations by varying dynamically the V/f ratio is proposed. The stability analysis and the effectiveness of the proposed method are verified with simulation results on a 2.8 kV-7.25 MW induction motor and with experimental tests on a small-scale 380 V-10 kW motor.