In this paper, a modified Z-source inverter (ZSI) with specific modulation techniques is proposed to reduce leakage currents in three-phase transformerless photovoltaic (PV) systems. The new topology only requires an additional fast-recovery diode when compared with the original structure. On the other hand, the pulsewidth modulation technique is entirely modified in order to reduce the leakage currents through the conduction path. Simulation results for the three-phase transformerless PV system operating in two cases, i.e., connected to a grid and connected to a grounded RL load, are presented. Experimental results of leakage currents in three-phase ZSIs connected to a RL load are obtained to validate the theoretical and simulation models.

This article reviews the nonsinusoidal CPWM and SVPWM techniques and deals with the three possibilities of calculation of pulsewidths after the addition of a zero-sequence signal. A general algorithm is proposed and adapted for dealing with the control of the three-level NPC inverter and also the Z-source converter. Experimental results corroborate the proposed technique.

This paper presents a comprehensive literature review with focus on the difficulties electric vehicles (EVs) face to charge the battery while on a trip, and proposes a solution without the need of an expensive change in infrastructure. The proposed method charges EVs while en route from another vehicle, which will be referred to as vehicle-to-vehicle recharging (VVR). The aim of this system is to bring an innovative way for EVs to charge their battery without getting off route on a highway. The electric vehicle can request such a service from a designated charger vehicle on demand and receive electric power wirelessly while en route. The vehicles that provide energy (charger vehicles) through wireless power transfer (WPT) only need to be semi-autonomous in order to engage/disengage during a trip. The state-of-the-art is divided into three subsections relevant to the proposed system and where most of the innovations to reduce the burden of charging EVs can be found: (1) infrastructure changes, (2) device level innovations, and (3) autonomous vehicles. The infrastructure changes highlight some of the proposed systems that aim to help EVs become a convenient solution to the public. Device level innovations covers some of the literature on technology that addresses EVs in terms of WPT. And finally, the autonomous vehicle subsection covers the importance of such technology in terms of safety and reliability, that could be implemented on the VVR system. Furthermore, modeling, analysis, and simulation is presented to validate the feasibility of the proposed system.

Shunt active power filters (SAPFs) implemented without harmonic detection schemes are susceptible to sudden load variations. This paper proposes a robust control strategy to reduce this drawback. In this strategy, the dc-link voltage is regulated by a hybrid control technique combining a standard proportional-integral PI and a sliding-mode (SM) controllers. The SM scheme continuously determines the gains of the PI controller based on the control loop error and its derivative. The chattering due to the SM scheme is reduced by a transition rule that fixes the controller gains when steady-state condition is reached. This controller is termed as dual-sliding-mode-proportional-integral. The phase currents of the power grid are indirectly regulated by double-sequence controllers with two degrees of freedom, where the internal model principle is employed to avoid reference frame transformation. The proposed control strategy ensures zero steady-state error and improves the performance under hard transients such as load variation. Additionally, it presents robustness when the SAPF is operating under unbalanced conditions. Experimental results demonstrate the performance of the proposed control scheme.

Single-phase to three-phase conversion using power electronics converters is a well-known technology, especially when the configurations and control strategies already established in the technical literature are considered. Regarding the configurations conceived over the years, it can be observed two main tendencies: 1) configurations with a reduced number of components; and 2) configurations with an increased number of components. The search for topologies with a reduced number of components was the trend over a long period of time. This can be, in part, explained by the high cost of the power switch when compared to the capacitor used in the dc-link bus. Then, the converter leg was sometimes substituted for the midpoint capacitor. However, as far as the price of the semiconductor was going down, such tendency has been changed, and now the configurations with an increased number of components do appear as an interesting option, especially in terms of reliability, efficiency, and distortions improvement. A comprehensive review of the two possibilities (reduced and increased number of components) has been considered in this paper. Also, the single-phase to three-phase ac-ac direct conversion configurations and those which aim to reduce the dc-link voltage fluctuation have been included. The goal of this paper is to provide a complete range on the status of single-phase to three-phase power conversion technologies to professionals and researchers interested in this topic.

This study presents single‐input double‐output unidirectional and bidirectional dc–dc buck converters, for applications that demand two dc‐controlled output voltages. The proposed converters present a component count reduction and it is considered as a monolithic device with two output voltages generated by the same power converter. The main advantages of the proposed converters are reduction of costs and better power losses distribution among the semiconductor devices. Besides the proposal of suitable power converters, this study presents their models, control strategies, modulation approaches and design specification. The selected simulated and experimental results are presented as well.