To enhance the photovoltaic (PV) power-generation conversion, maximum power point tracking (MPPT) is the foremost constituent. This article introduces an adaptive neuro-fuzzy inference system–particle swarm optimization (ANFIS–PSO)-based hybrid MPPT method to acquire rapid and maximal PV power with zero oscillation tracking. The inverter control strategy is implemented by a space vector modulation hysteresis current controller to get quality inverter current by tracking accurate reference sine-shaped current. The ANFIS–PSO-based MPPT method has no extra sensor requirement for measurement of irradiance and temperature variables. The employed methodology delivers remarkable driving control to enhance PV potential extraction. An ANFIS–PSO-controlled Zeta converter is also modeled as an impedance matching interface with zero output harmonic agreement and kept between PV modules and load regulator power circuit to perform MPPT action. The attainment of recommended hybrid ANFIS–PSO design is equated with perturb and observe, PSO, ant colony optimization, and artificial bee colony MPPT methods for the PV system. The practical validation of the proposed grid-integrated PV system is done through MATLAB interfaced dSPACE interface and the obtained responses accurately justify the proper design of control algorithms employed with superior performance.

An Experimental Estimation of Hybrid ANFIS–PSO-Based MPPT for PV Grid Integration Under Fluctuating Sun Irradiance

Inductive components such as line filter inductors or transformers occupy a significant amount of space in today's power electronic systems, and furthermore, considerable losses occur in these components. A main application of inductive components is EMI filters, as, e.g., employed for the attenuation of switching frequency harmonics of power factor correction (PFC) rectifier systems. In this paper, a design procedure for the mains side LCL filter of an active three-phase rectifier is introduced. The procedure is based on a generic optimization approach, which guarantees a low volume and/or low losses. Different designs are calculated to show the tradeoff between filter volume and filter losses. The design procedure is verified by experimental measurements. Furthermore, an overall system optimization, i.e., an optimization of the complete three-phase PFC rectifier, is given.

Optimal Design of LCL Harmonic Filters for Three-Phase PFC Rectifiers

Maximum power point trackers (MPPT) are required in order to obtain optimal photovoltaic power. To achieve this task, an intelligent fuzzy particle swarm optimization (FPSO) MPPT algorithm has been proposed in this paper. Also an inverter control strategy has been gated with a ripple factor compensation-based modified space vector pulse width modulation (SVPWM) method. The proposed system performance is verified under varying sun irradiance, partial shadow, and loading conditions. For load bus voltage regulation, the buck-boost Zeta converter is selected due to least ripple voltage output. The experimental responses verify the efficiency and improved system performance, which is realized through a MATLAB/Simulink interfaced dSPACE DS1104 real-time board. The proposed MPPT and inverter current controller provides high tracking efficiency and anti-islanding protection with superior dynamic control of the system performance by injecting sinusoidal inverter current to the utility grid. The novelty of this paper is experimental implementation and verification of FPSO-based hybrid MPPT as well as modified SVPWM inverter control has neither been discussed nor implemented before using dSPACE platform by the author's best review.

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An Extensive Practical Investigation of FPSO-Based MPPT for Grid Integrated PV System Under Variable Operating Conditions With Anti-Islanding Protection

Module integrated converters (MICs) in single phase have witnessed recent market success due to unique features such as improved energy harvest, improved system efficiency, lower installation costs, plug-and-play operation, and enhanced flexibility and modularity. The MIC sector has grown from a niche market to mainstream, especially in the United States. Assuming further expansion of the MIC market, this paper presents the microinverter concept incorporated in large size photovoltaic (PV) installations such as megawatts (MW)-class solar farms where a three-phase ac connection is employed. A high-efficiency three-phase MIC with two-stage zero voltage switching (ZVS) operation for the grid-tied PV system is proposed which will reduce cost per watt, improve reliability, and increase scalability of MW-class solar farms through the development of new solar farm system architectures. The first stage consists of a high-efficiency full-bridge LLC resonant dc-dc converter which interfaces to the PV panel and produces a dc-link voltage. A center points iteration algorithm developed specifically for LLC resonant topologies is used to track the maximum power point of the PV panel. The second stage is comprised of a three-phase dc-ac inverter circuit which employs a simple soft-switching scheme without adding auxiliary components. The modeling and control strategy of this three-phase dc-ac inverter is described. Because the dc-link capacitor plays such an important role for dual-stage MIC, the capacitance calculation is given under type D voltage dip conditions. A 400-W prototype was built and tested. The overall peak efficiency of the prototype was measured and found to be 96% with 98.2% in the first stage and 98.3% in the second stage.

Design and Implementation of Three-Phase Two-Stage Grid-Connected Module Integrated Converter

This article proposes an approach for realizing the power delivery scheme for an extreme fast charging (XFC) station that is meant to simultaneously charge multiple electric vehicles (EVs). A cascaded H-bridge converter is utilized to directly interface with the medium voltage grid while dual-active-bridge based soft-switched solid-state transformers are used to achieve galvanic isolation. The proposed approach eliminates redundant power conversion by making use of partial power rated dc–dc converters to charge the individual EVs. Partial power processing enables independent charging control over each EV, while processing only a fraction of the total battery charging power. Practical implementation schemes for the partial power charger unit are analyzed. A phase-shifted full-bridge converter-based charger is proposed. Design and control considerations for enabling multiple charging points are elucidated. Experimental results from a down-scaled laboratory test-bed are provided to validate the control aspects, functionality, and effectiveness of the proposed XFC station power delivery scheme. With a down-scaled partial power converter that is rated to handle only 27% of the battery power, an efficiency improvement of 0.6% at full-load and 1.6% at 50% load is demonstrated.

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An Approach Towards Extreme Fast Charging Station Power Delivery for Electric Vehicles with Partial Power Processing

This paper proposes a novel approach to reduce the power processed by series-connected partial-power converters (S-PPC) applied to string/multistring level maximum power point tracking photovoltaic systems. A design procedure based on the definition of the voltage regulation range is presented. It introduces an additional degree of freedom that allows a proper design of the converter in order to reduce not only the active power but also the nonactive power, reducing losses and increasing power density. By means of the proposed approach, it is also demonstrated that by replacing the conventional step-up partial-power converter by a step-up/down partial-power converter, the active and nonactive power can be further reduced, allowing to better explore the benefits of the partial-power concept. In order to validate the proposed approach, two 750-W prototypes of full-bridge S-PPC and full-bridge/push–pull S-PPC were implemented and experimentally evaluated. The step-up/down prototype presented a reduction of 46.9% in nonactive power and 23.4% of its volume, resulting in a higher efficiency and power density in comparison to the voltage step-up prototype counterpart.

Series-Connected Partial-Power Converters Applied to PV Systems: A Design Approach Based on Step-Up/Down Voltage Regulation Range

This paper proposes an analytical methodology to evaluate the power processed by dc–dc converters operating as series voltage regulators, which provide an alternative to increase efficiency in photovoltaic systems. Via the analysis of both active and nonactive power processing, the proposed methodology allows to clearly distinguish among circuit topologies as truly partial-power processing (PPP) or just partial active power processing topologies. When an isolated dc–dc topology is connected in series as a voltage regulator, the overall processed power can be reduced, which reduces power losses and improves efficiency. Conversely, this paper also demonstrates that some series-regulator topologies may not actually reduce the proportion of nonactive processed power. To demonstrate the applications of the proposed methodology and to emphasize its significance, two well-known series-connected voltage regulators (flyback and full-bridge phase shift) and a full-power regulator (boost) were evaluated. The results indicate that the full-bridge series regulator can perform a true PPP, whereas the flyback series-regulator processes the same amount of power as that processed by conventional nonisolated boost converters and cannot be considered a partial-power topology. This study finding contradicts assertions in the literature that this topology achieves high-efficiency dc–dc conversion through PPP. To confirm the theoretical analysis, experimental results from three 750-W prototypes are presented alongside its simulations.

Evaluation of Power Processing in Series-Connected Partial-Power Converters

This paper proposes the concept and the synthesis methodology of simplified zero-voltage-transition (ZVT) circuits applied to bidirectional pulsewidth modulation poles The main goal of simplified ZVT circuits is to make possible the use of conventional modulation schemes to accomplish better converter performance and to eliminate the synchronous-switching requirements imposed by ZVT integrated multipole topologies To derive the simplified ZVT circuits, a synthesis methodology is proposed based on the generalization of the ZVT technique, where the restrictions to achieve the zero-voltage switching for the main converter switches are identified Thereafter, a set of simplified semiconductor switches composed by only one high-frequency switch is defined to be used in the simplified ZVT auxiliary circuits Thus, using the proposed synthesis methodology, any simplified ZVT topology can be derived, whether or not they have appeared in a previous publication In order to validate the proposed approach, experimental results for a three-phase ZVT inverter, employing the minimum-loss space vector modulation and operating at 15 kW and 20 kHz are presented The prototype presented an efficiency of 98% at full load representing an improvement of 05% when compared to its hard-switched counterpart and 18% when compared to an integrated ZVT topology

Simplified Zero-Voltage-Transition Circuits Applied to Bidirectional Poles: Concept and Synthesis Methodology

A Review of Series-Connected Partial Power Converters for DC–DC Applications

This paper discusses about the partial power processing concept applied to DC/DC converters, which has been presented in the literature as an option to be used on voltage regulators in several applications such as photovoltaic systems. The purpose of this paper is to elucidate the partial power processing concept and demonstrate that, opposing the sense created in the literature, the fact that a converter performs partial active power processing does not necessarily means that their efficiency and/or power density will be higher than that of a standard converter that processes full active power. It is shown that the performance of DC/DC converter depends not only on its active power, but also on nonactive power that flows inside the converter and the nonactive power drained from source and/or supplied to the load. To demonstrate it, the nonactive power is evaluated on a partial active power buck-boost converter and a new approach is proposed to quantify the total power handled by a DC/DC power converter. Experimental results are presented in order to confirm the analysis.

Jonatan Rafael Rakoski Zientarski

Papers

Series-Connected Partial-Power Converters Applied to PV Systems: A Design Approach Based on Step-Up/Down Voltage Regulation Range

Evaluation of Power Processing in Series-Connected Partial-Power Converters

Simplified Zero-Voltage-Transition Circuits Applied to Bidirectional Poles: Concept and Synthesis Methodology

A Review of Series-Connected Partial Power Converters for DC–DC Applications

Understanding the partial power processing concept: A case-study of buck-boost dc/dc series regulator