The alarming situation of global warming leads to the full adoption of the renewable energy-based transportation system. However, their sustainable deployment at a mass level has been a challenging task. This article presents the design aspects and practical implementation of the modern solar-assisted level-2 electric vehicle charging station which is controlled by a Type-1 vehicle connector. The designed model is developed in MATLAB/Simulink environment, the circuit operation is examined and its methodological model is derived to study the parametric design features. Furthermore, the complete hardware setup has developed to test the performance of the power factor correction under the steady-state condition with respect to variation in load for the input of 3 kW, 230 Vrms at 1-phase, 50 Hz rated, and to produce a 48 V buck converter dc output. The 6.4 kW solar photovoltaic (PV) charging station, installed at the Centre of Advanced Research in Electrified Transportation building parking area in Aligarh Muslim University campus, selected as a case site. Moreover, the controller circuit is simulated in PROTEUS software and a prototype model has been tested in the lab. The study is performed on a 10 kWh lithium-ion battery pack on a bright sunny day at standard test condition of the solar panel.

System Design and Realization of a Solar-Powered Electric Vehicle Charging Station

In this article, a new bidirectional single-stage interleaved totem-pole electrolytic capacitorless ac–dc converter with high-frequency isolation and low components count is proposed. The proposed converter is constructed using nonregulating two-phase interleaved totem-pole converter switched with a fixed 50% duty on the grid side and a full-bridge on the dc-side for active power and dc output regulation. This switching method results in a ripple-free grid current regardless of the magnitude of the input inductances. Consequently, a proper design of input inductance secures soft switching for all switches under wide voltage and load ranges without an auxiliary circuit or resonant tank. Hence, the proposed topology overcomes the reverse recovery issue, thereby enabling the use of Si devices in CCM. Moreover, the current spike around the ac main zero-crossing is avoided in the CCM operation due to small rectified voltage around zero-crossing. Furthermore, the instantaneous powers at the grid side and dc-side are identical since the proposed topology is electrolytic capacitorless with inherent second harmonic ripple current at the dc-side. PFC is inherently performed in the proposed converter without a current shaping control loop, and the phase-shift angle is the only control variable. Hence, the control system is simple and reliable. A 3.3 kW prototype of the proposed converter is built and tested in order to verify the performance and the theoretical claims.

Interleaved Totem-Pole ZVS Converter Operating in CCM for Single-Stage Bidirectional AC–DC Conversion With High-Frequency Isolation

Hybrid ac–dc microgrids (HMG) have become more popular recently because of their superior features in comparison with pure ac and dc microgrids (MGs). HMGs have fewer power converters and are more flexible than pure ac and dc MGs, but the number of converters in HMG is still significant, especially when the dc part of HMG has several voltage levels. A new simplified and more flexible architecture for HMGs that features a new multiport interlinking converter (IC) is proposed in this article. Using the proposed IC, the number of power electronic converters in an HMG with several dc bus voltages can be reduced without increasing the number of active switches in the IC or the complexity of its control system. In this article, the new simplified HMG architecture is presented, and the operation of the proposed IC as a single unit and as a part of a simplified HMG are explained, along with its features. Experimental results obtained from a scaled-down prototype are also presented to confirm the feasibility of the multiport interlinking converter. Simulation results that show the effect of load variations in the intermediate bus architecture dc bus on the operation of the HMG are also presented as well.

Simplified Hybrid AC–DC Microgrid With a Novel Interlinking Converter

This paper proposes a soft-switched modulation technique with synchronous rectification for an isolated single-stage single-phase matrix-type dc–ac converter. The dc side consists of a full bridge inverter, and the ac side is a 2×2 matrix converter-based cycloconverter. The proposed unipolar modulation strategy provides zero current switching/zero voltage switching (ZVS) for the ac side devices and ZVS-on for the dc side devices. It also allows natural commutation of the current flowing through the secondary side leakage inductor of the isolation transformer and the grid inductor during unity power factor (UPF) condition, thus eliminates the requirement of snubber circuit. An improved soft-switched flyback-based regenerative snubber circuit is also presented for non-UPF operation. Proposed snubber circuit recycles the energy stored in the snubber capacitors in every switching cycle. A guideline to design snubber circuit along with a comparative study is discussed in this paper. Performance of the proposed hybrid modulation technique is evaluated in an SiC mosfet based 1.2-kW dc–ac converter prototype. A detailed analysis of the converter performance has been presented in this paper considering the circuit non-idealities.

Soft-Switched Modulation Technique for a Single-Stage Matrix-Type Isolated DC–AC Converter

Due to the continuously increasing demand on switched-mode power converters (i.e., dc–dc, dc–ac, ac–dc, and ac–ac) that can achieve high efficiency at high switching frequency, soft-switching techniques have received much attention in the area of power converter applications over recent years. This article provides a comprehensive review of the state-of-the-art soft-switching techniques used to achieve the zero-voltage switching and zero-current switching supplied by power switching devices. First, the auxiliary-circuit-based and nonauxiliary-circuit-based techniques that perform soft switching are systematically classified according to power converter. Next, soft-switching techniques for each power converter are comprehensively classified and reviewed in detail. Unlike the existing review papers that only categorize the soft-switching techniques used in dc choppers and inverters, this article offers further helpful categorization for all types of power converters. Further, it provides the merits, demerits, and suitable applications for each soft-switching technique. Finally, it suggests future research issues for soft-switching techniques in power converters.

A State-of-the-Art Review on Soft-Switching Techniques for DC–DC, DC–AC, AC–DC, and AC–AC Power Converters

This paper presents a novel single-stage ac/dc rectifier with high-frequency isolation and bidirectional power flow capability, which is feasible to connect dc grids to ac ones. A thorough analysis is performed based on the development of an actual model as well as a fundamental one using the double-sideband amplitude modulation equations. The derived models allow the determination of the active and reactive power flow through the transformer as well as defining the operating regions for which soft commutation is achieved. Besides, the current stresses of the semiconductors devices are analyzed in detail. Experimental results obtained from a 5 kW prototype are presented and discussed in order to validate the proposed model as well as demonstrate the converter's performance and claimed advantages. The proposed concept can also be extended to dc/dc, ac/ac, and multilevel topologies.

A Single-Stage Three-Phase Bidirectional AC/DC Converter With High-Frequency Isolation and PFC

This paper presents a single-phase ac–dc–ac converter with high-frequency isolation, which employs the interleaved technique. The proposed converter is suitable for power quality applications, such as dynamic voltage restorers, uninterruptable power supplies, and voltage regulators. The modeling of power flow is presented, focusing on the minimization of the transformer current. This analysis is improved by the introduction of the actuators type concept, which ensures reduced current through the transformer. Moreover, the effective longitudinal inductance of the series association of the boost inductor and two interphase transformers is determined. The soft-switching regions are also obtained as well as their dependency on the phase-shift angle. The proposed converter is compared with one indirect ac–dc–ac topology, which uses the dual active bridge converter as the isolation stage. Experimental results are obtained to show that the proposed converter is able to provide power factor correction, mitigate voltage sags, and regulate the output voltage.

High-Frequency Isolated AC–DC–AC Interleaved Converter for Power Quality Applications

This paper proposes the use of the three-phase single-stage bidirectional ac-dc converter with high frequency isolation as a multiport power converter. The presented topology is suitable for the new concept of distributed generation, or smart-grids, interconnecting various sources and loads, controlling the power flow between them, with only one converter. The phase-shift angle between the primary and secondary side controls the power flow of the converter which is based on the three-phase version of the dual active bridge and associated with the three-state-switching cell. Therefore, a center tap is used in the secondary windings as well as a modified modulation in order to avoid the low frequency content in the third port.

Multi-port bidirectional three-phase AC-DC converter with high frequency isolation

This paper presents the design and implementation of a control strategy for a single-phase/-stage pulse-width modulated PFC rectifier. The selected rectifier topology is based on the known unidirectional buck/boost-type pulse-width modulated buck + boost converter. This topology presents step-up and step-down features in a single-stage power processing. and is suited for on-board battery charger in plug-in electric vehicles applications. A laboratory prototype designed for rated output power of 1 kW and operating with a switching frequency of 25kHz, rms ac mains voltage 220V and output voltage of 162V is constructed and tested experimentally. At full load condition, an efficiency of 96.5% and a high power factor above 0.99 are achieved and IEC 61000–3–2 requirements are complied.

Design and Control for a Single-Phase/-Stage Buck/Boost-Type PWM PFC Rectifier

This paper proposes a multi-port, single-phase ac-dc converter with high frequency isolation and bidirectional power flow capability, which is suitable for distributed generation, interconnecting various sources and loads, and controlling the power flow between them in an integrated conversion stage. Three-state switching cells and interleaved converters are employed in order to achieve high power processing capability. In order to verify the feasibility of this topology, it is presented the principle of operation, theoretical analysis, control strategy and simulation waveforms. Some experimental results are presented for a 1 kW laboratory prototype under construction.

Bruno Ricardo de Almeida

Papers

A Single-Stage Three-Phase Bidirectional AC/DC Converter With High-Frequency Isolation and PFC

High-Frequency Isolated AC–DC–AC Interleaved Converter for Power Quality Applications

Multi-port bidirectional three-phase AC-DC converter with high frequency isolation

Design and Control for a Single-Phase/-Stage Buck/Boost-Type PWM PFC Rectifier

Single-Stage Single-phase AC/DC Converter with High Frequency Isolation Feasible to Microgeneration