scholarly journals Equivalent Two Switches and Single Switch Buck/Buck-Boost Circuits for Solar Energy Harvesting Systems

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 583
Author(s):  
Ehsan Jamshidpour ◽  
Slavisa Jovanovic ◽  
Philippe Poure

In this paper, a comparative analysis has been presented of two equivalent circuits of non-isolated buck/buck-boost converters under synchronous control, used in a stand-alone Photovoltaic-battery-load system. The first circuit consists of two cascaded buck and buck-boost classical converters with two controllable switches. The buck converter is used to extract the maximum power of the Photovoltaic source, and the buck-boost converter is applied for the output voltage level control. The second circuit consists of a proposed converter with a single controllable switch. In both cases, the switching frequency is used to track the maximum power point and the duty ratio controls the output voltage level. Selected simulation results and experimental tests confirm that the two conversion circuits have identical behavior under synchronous control. This study shows that the single switch converter has a lower size and cost, but it is limited in the possible control strategy.

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1131 ◽  
Author(s):  
Mauricio Dalla Vecchia ◽  
Giel Van den Broeck ◽  
Simon Ravyts ◽  
Johan Driesen

This paper explores and presents the application of the Inductor–Diode and Inductor-Capacitor-Diode structures in a DC–DC step-down configuration for systems that require voltage adjustments. DC micro/picogrids are becoming more popular nowadays and the study of power electronics converters to supply the load demand in different voltage levels is required. Multiple strategies to step-down voltages are proposed based on different approaches, e.g., high-frequency transformer and voltage multiplier/divider cells. The key question that motivates the research is the investigation of the aforementioned Inductor–Diode and Inductor–Capacitor–Diode, current multiplier/divider cells, in a step-down application. The two-stage buck converter is used as a study case to achieve the output voltage required. To extend the intermediate voltage level flexibility in the two-stage buck converter, a second switch was implemented replacing a diode, which gives an extra degree-of-freedom for the topology. Based on this modification, three regions of operation are theoretically defined, depending on the operational duty cycles δ2 and δ1 of switches S2 and S1. The intermediate and output voltage levels are defined based on the choice of the region of operation and are mapped herein, summarizing the possible voltage levels achieved by each configuration. The paper presents the theoretical analysis, simulation, implementation and experimental validation of a converter with the following specifications; 48 V/12 V input-to-output voltage, different intermediate voltage levels, 100 W power rating, and switching frequency of 300 kHz. Comparisons between mathematical, simulation, and experimental results are made with the objective of validating the statements herein introduced.


2020 ◽  
Vol 29 (12) ◽  
pp. 2050193 ◽  
Author(s):  
K. T. Ajmal ◽  
K. Muhammedali Shafeeque ◽  
B. Jayanand

A novel Four Switch Infinite Level Inverter (FSILI) is proposed in this paper. In conventional multilevel inverters, as the number of levels increases the output voltage becomes more sinusoidal. Unlike conventional multilevel topologies, the output voltage level in the proposed topology depends upon the switching frequency. Since the switching frequency is very high, the output voltage level approaches infinity, thus the name Infinite Level Inverter. Proposed topology requires only one inductor and capacitor reducing the size, weight and thus cost of the overall system. Inherent buck operation is happening in the proposed topology with a sine varying duty ratio PWM control. Steady-state analysis and design of the inverter are carried out. The proposed topology is simulated using Matlab/Simulink to evaluate the theoretical analysis and operation. A hardware prototype is also developed to validate the operation of proposed FSILI.


Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 117
Author(s):  
Yu-Kai Chen ◽  
Hong-Wen Hsu ◽  
Chau-Chung Song ◽  
Yu-Syun Chen

This paper proposes the design and implementation of inductor-inductor-capacitor (LLC) converters with modules connected in series with the power scan method and communication scan network (CSN) to achieve MPPT and regulate the output voltage for the PV micro-grid system. The Dc/Dc converters includes six isolated LLC modules in series to supply ±380 V output voltage and track the maximum power point of the PV system. The series LLC converters are adopted to achieve high efficiency and high flexibility for the PV micro-grid system. The proposed global maximum power scan technique is implemented to achieve global maximum power tracking by adjusting the switching frequency of the LLC converter. To improve the system flexibility and achieve system redundancy, module failure can be detected in real time with a communication scan network, and then the output voltage of other modules will be changed by adjusting the switching frequency to maintain the same voltage as before the failure. Additionally, the proposed communication scan network includes the RS-485 interface of the MPPT series module and the CAN BUS communication interface with other subsystems’ communication for the PV micro-grid application system. Finally, a 6 kW MPPT prototype with a communication scan network is implemented and the proposed control method is verified for the PV system.


Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1379 ◽  
Author(s):  
Umberto Abronzini ◽  
Ciro Attaianese ◽  
Matilde D’Arpino ◽  
Mauro Di Monaco ◽  
Giuseppe Tomasso

Neutral Point Clamped (NPC) converters with n levels are traditionally controlled in such a way that the DC-link capacitors operate at 1/( n - 1) of the total DC-link voltage level. The voltage level across the DC-link capacitors has to be properly regulated by the capacitor unbalance control to contain the harmonic distortion of the converter output voltages. State-of-the-art modulation techniques address the problem of the DC-link voltage regulation for NPC inverters. However, they highly show reduced performance when unbalanced DC-link voltages are considered. In this paper, a novel Space Vector Modulation (SVM) is proposed for NPC converters with an unbalanced DC-link. At every modulation interval, the technique defines the optimal switching pattern by considering the actual unbalanced DC-link conditions. The proposed modulation allows improving the harmonic content of the NPC converter output voltage with respect to a traditional ML-SVM, when the same operating conditions are considered. As an extension, the proposed modulation technique will guarantee the same output voltage quality of a traditional ML-SVM with unbalanced DC-link, while improving the conversion efficiency thanks to a reduction of switching frequency.


Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2321
Author(s):  
Mohammad Tayyab ◽  
Adil Sarwar ◽  
Irfan Khan ◽  
Mohd Tariq ◽  
Md Reyaz Hussan ◽  
...  

A new triple voltage boosting switched-capacitor multilevel inverter (SCMLI) is presented in this paper. It can produce 13-level output voltage waveform by utilizing 12 switches, three diodes, three capacitors, and one DC source. The capacitor voltages are self-balanced as all the three capacitors present in the circuit are connected across the DC source to charge it to the desired voltage level for several instants in one fundamental cycle. A detailed comparative analysis is carried to show the advantages of the proposed topology in terms of the number of switches, number of capacitors, number of sources, total standing voltage (TSV), and boosting of the converter with the recently published 13-level topologies. The nearest level control (NLC)-based algorithm is used for generating switching signals for the IGBTs present in the circuit. The TSV of the proposed converter is 22. Experimental results are obtained for different loading conditions by using a laboratory hardware prototype to validate the simulation results. The efficiency of the proposed inverter is 97.2% for a 200 watt load.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5911
Author(s):  
Hsiao-Hsing Chou ◽  
Hsin-Liang Chen

This paper presents a buck converter with a novel constant frequency controlled technique, which employs the proposed frequency detector and adaptive on-time control (AOT) logic to lock the switching frequency. The control scheme, design concept, and circuit realization are presented. In contrast to a complex phase lock loop (PLL), the proposed scheme is easy to implement. With this novel technique, a buck converter is designed to produce an output voltage of 1.0–2.5 V at the input voltage of 3.0–3.6 V and the maximum load current of 500 mA. The proposed scheme was verified using SIMPLIS and MathCAD. The simulation results show that the switching frequency variation is less than 1% at an output voltage of 1.0–2.5 V. Furthermore, the recovery time is less than 2 μs for a step-up and step-down load transient. The circuit will be fabricated using UMC 0.18 μm 1P6M CMOS processes. The control scheme, design concept and circuit realization are presented in this paper.


2021 ◽  
Vol 2 (2) ◽  
pp. 162-167
Author(s):  
Haris Masrepol ◽  
Muldi Yuhendri

Solar panels are a renewable energy power plant that uses sunlight as its main energy source. The power generated by solar panels are determined by the size of the solar panels, solar radiation and temperature. The power of the solar panels is also determined by the output voltage of the solar panels. To get the maximum output power at any time, it is necessary to adjust the output voltage of the solar panel. This study proposes controlling the maximum output power of solar panels, also known as maximum power point tracking (MPPT) by adjusting the output voltage of the solar panels using a buck converter. The buck converter output voltage regulation at the maximum power point of the solar panel is designed with the Perturbation and Observation (PO) algorithm which is implemented using an Arduino Mega 2560. This MPPT control system is applied to 4x50 Watt-Peak (WP) solar panels which are connected in parallel. The experimental results show that the proposed MPPT control system with the PO algorithm has worked well as expected. This can be seen from the output power generated by the solar panels already around the maximum power point at any change in solar radiation and temperature.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5380
Author(s):  
Kornel Wolski ◽  
Piotr Grzejszczak ◽  
Marek Szymczak ◽  
Roman Barlik

Phase-Shifted Full Bridge (PSFB) topology in its four-diode variant is the choice with the lowest part count in applications that demand high power, high voltage, and galvanic isolation, such as in Electric Vehicle (EV) chargers. Even though the topology is prevalent in power electronics applications, no single, unified analytical model has been proposed for the design process of four-diode PSFB converters. As a result, engineers must rely on simulations and empirical results obtained from previously built converters when selecting components to properly match the DC source voltage level with the DC load voltage requirements. In this work, the authors provide a design-oriented analysis approach for obtaining the output voltage and semiconductor current values, ready for implementation in a spreadsheet- or MATLAB-type software to automate design optimization. The proposed formulas account for all the first-order nonlinear dependencies by considering the impact of each of the following eight design parameters: DC-link voltage, load resistance, phase-shift ratio, switching frequency, transformer turns ratio, magnetizing inductance, series inductance, and output inductance. The results are verified through experiments at the power level of 10 kW and the DC-link voltage level of 800 V by using a grid simulator and a SiC-based two-level Active Front End (AFE) with a DC–DC stage based on the PSFB topology. The accuracy of the output voltage formula is determined to be around 99.6% in experiments and 100.0% in simulations. Based on this exact model, an automated design procedure for high-power high-voltage SiC-based PSFB converters is developed. By providing the desired DC-link voltage, output voltage, output power, output current ripple factor, maximum temperatures, and semiconductor and heatsink databases, the algorithm calculates a set of feasible designs and points to the one with the lowest semiconductor losses, dimensions, or cost.


Author(s):  
Bachar Meryem ◽  
Naddami Ahmed ◽  
Fahli Ahmed

The maximum power point tracking (MPPT) algorithms ensure optimal operation of a photovoltaic (PV) system to extract the maximum PV power, regardless of the climatic conditions. This paper exposes the study, design, simulation and implementation of a modified advanced neural fuzzy inference system (ANFIS) MPPT algorithm based on fuzzy data for a PV system. The studied system includes a PV array, a DC/DC buck converter, the ANFIS controller, a proportional-integral (PI) controller, and a load. The simulation and experimental tests are carried out with the MATLAB/Simulink software and LabVIEW, respectively. Moreover, the obtained results are compared with previously published results by incremental conductance (IC) and fuzzy logic (FL) algorithms under different climatic conditions of irradiation and temperature. The results show that the proposed ANFIS algorithm is able to track the maximum power point for varying climatic conditions. Furthermore, the comparison analysis reveals that the PV system using ANFIS algorithm has more efficient and better dynamic response than FL and IC.


Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1451
Author(s):  
Po Li ◽  
Xiang Li ◽  
Tao Zeng

Interleaved DC-DC converters have been widely used in power conversion due to their high efficiency and reliability. In the application of new energy, this plays an increasingly important role in the grid-connected power generation of wind, solar, and tidal energy. Therefore, it is crucial to ensure the reliability and proper operation of interleaved DC-DC converters. We studied an open circuit fault (OCF) diagnosis method for a three-phase interleaved buck converter. We propose a non-invasive diagnosis method based on the output voltage using the harmonic amplitude and phase at the switching frequency as the diagnostic criteria. Evaluation was carried out on a hardware-in-the-loop (HIL) test platform to prove the validity of the proposed method. The results show that the presented method had high accuracy and robustness against OCFs, which could otherwise damage the system.


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