scholarly journals PV String‐Level Isolated DC–DC Power Optimizer with Wide Voltage Range

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1889
Author(s):  
Hyungjin Kim ◽  
Gibum Yu ◽  
Jaehoon Kim ◽  
Sewan Choi
Keyword(s):  
Load Condition ◽  
Electrolytic Capacitor ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Pwm Control ◽  
Pulse Frequency Modulation ◽  
Voltage Range ◽  
Soft Start ◽  
Dc Power ◽  
Control Scheme

This paper proposes a photovoltaic (PV) string-level isolated DC–DC power optimizer with wide voltage range. A hybrid control scheme in which pulse frequency modulation (PFM) control and pulse width modulation (PWM) control are combined with a variable switching frequency is employed to regulate the wide PV voltage range. By adjusting the switching frequency in the above region during the PWM control process, the circulating current period can be eliminated and the turn-on period of the bidirectional switch of the dual-bridge LLC (DBLLC) resonant converter is reduced compared to that with a conventional PWM control scheme with a fixed switching frequency, resulting in better switching and conduction loss. Soft start-up control under a no-load condition is proposed to charge the DC-link electrolytic capacitor from 0 V. A laboratory prototype of a 6.25 kW DBLLC resonant converter with a transformer, including integrated resonant inductance, is built and tested in order to verify the performance and theoretical claims.

scholarly journals Bidirectional Interface Resonant Converter for Wide Voltage Range Storage Applications

2021 ◽  
Vol 14 (1) ◽  
pp. 377
Author(s):  
Mouncif Arazi ◽  
Alireza Payman ◽  
Mamadou Baïlo Camara ◽  
Brayima Dakyo
Keyword(s):  
Electromagnetic Compatibility ◽  
Narrow Range ◽  
Harmonic Approximation ◽  
Design Procedure ◽  
Resonant Circuit ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Voltage Range ◽  
Wide Range ◽  
Storage Units

In this paper, a bidirectional zero voltage switching (ZVS) resonant converter with narrow control frequency deviation is proposed. Wide input–output voltage range applications, such as flywheel or supercapacitors storage units are targeted. Due to symmetrical topology of resonant circuit interfaces, the proposed converter has similar behavior in bidirectional operating mode. We call it Dual Active Bridge Converter (DABC). The proposal topology of the converter is subjected to multi resonant circuits which make it necessary to study with multiscale approaches. Thus, first harmonic approximation and use of selective per unit parameters are established in (2) Methods. Then, the forward direction and backward direction of power flux exchange are detailed according to switching sequences. Switching frequency control must be completed within a narrow range. So, the frequency range deterministic parameters are emphasized in the design procedure in (3) Methods. A narrow range of switching frequency and a wide range voltage control must be ensured to suit for energy storage units, power electronic devices capabilities and electromagnetic compatibility. A 3 kW test bench is used to validate operation principles and to proof success of the developed design procedure. The interest of proposed converter is compared to other solutions from the literature in (4) Results.

Analysis and Performance Evaluation of Control Methods for LLC Resonant Converter

2018 ◽  
Vol 15 (2) ◽  
pp. 685-689
Author(s):  
Soundiraraj Nallasamy ◽  
Rajasekaran Vairamani
Keyword(s):  
Frequency Modulation ◽  
Short Circuit ◽  
Load Condition ◽  
Pulse Frequency ◽  
Open Loop ◽  
Resonant Circuit ◽  
Frequency Variation ◽  
Switching Frequency ◽  
Pulse Frequency Modulation ◽  
Tank Circuit

An LLC resonant dc to dc converter in the company of an LC ant resonant tank circuit for civilizing the act of pulse frequency modulation (PFM) is projected in this manuscript. The planned converter, known as LLC-LC converter, can expand a voltage guideline area below the unity gain with a lesser frequency variation of Pulse frequency modulation by the effect of the antiresonant tank. This beneficial possessions contribute for shielding over current in the case of the short-circuit load condition as well as the bring into being interval in the planned band of switching frequency. The circuit topology and working theory of the planned converter is described, subsequent to the design method of the working frequency and circuit parameters are offered. The performance of the soft switch and the steady-state pulse frequency modulation distinctiveness of the LLC-LC converter are evaluated underneath the open-loop control in conduct experiment of a 2.0-kiloWatts trial product, and its real effectiveness is compared with an LLC converter model. Intended for enlightening the usefulness of the LLC-LC resonant circuit, voltages and currents of the series and ant resonant tanks are analyzed, correspondingly, with state-plane trajectory based on computation and experimentation, where by the power and energy of resonant tank is verified. To conclude, the possibility of the projected converter is evaluate from the realistic point of vision.

scholarly journals High Efficiency Isolated On-Board EV Battery Charger Using LLC Resonant Converter

2021 ◽  
Author(s):  
Sevilay Cetin ◽  
Keyword(s):  
Output Voltage ◽  
High Efficiency ◽  
Load Condition ◽  
Voltage Regulation ◽  
Resonant Converter ◽  
Battery Charger ◽  
Voltage Range ◽  
Wide Range ◽  
Electrical Vehicle ◽  
Llc Resonant Converter

In this study, high efficiency design of an on-board Electrical Vehicle (EV) battery charger is presented. The presented charger has two stages where the first stage is conventional front-end boost converter and the second stage is LLC resonant converter. The basic principles of both stage are discussed and the detailed design procedures are presented in terms of wide range output voltage regulation, wide range load condition, high efficiency and high power density. The presented design approach is tested with a prototype implemented with 2.5 kW output power at 250 V-450 V output voltage range. The peak efficiency of system is obtained as 95.53% at full load condition.

scholarly journals Wide Voltage Resonant Converter Using a Variable Winding Turns Ratio

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 370 ◽  
Author(s):  
Bor-Ren Lin ◽  
Chu-Xian Dai
Keyword(s):  
Low Voltage ◽  
Field Effect Transistors ◽  
Oxide Semiconductor ◽  
Resonant Circuit ◽  
Frequency Variation ◽  
Switching Frequency ◽  
Voltage Gain ◽  
Resonant Converter ◽  
Voltage Range ◽  
Llc Resonant Converter

This paper presents a inductor–inductor–capacitor (LLC) resonant converter with variable winding turns to achieve wide voltage operation (100–400 V) and realize soft switching operation over the entire load range. Resonant converters have been developed for consumer power units in computers, power servers, medical equipment, and adaptors due to the advantages of less switching loss and better circuit efficiency. The main disadvantages of the LLC resonant converter are narrow voltage range operation owing to wide switching frequency variation and limited voltage gain. For computer power supplies with hold-up time function, electric vehicle battery chargers, and for power conversion in solar panels, wide input voltage or wide output voltage operation capability is normally demanded for powered electronics. To meet these requirements, the variable winding turns are used in the presented circuit to achieve high- or low-voltage gain when Vin is at low- or high-voltage, respectively. Therefore, the wide voltage operation capability can be implemented in the presented resonant circuit. The variable winding turns are controlled by an alternating current (AC) power switch with two back-to-back metal-oxide-semiconductor field-effect transistors (MOSFETs). A 500-W prototype is implemented and test results are presented to confirm the converter performance.

scholarly journals Hybrid Resonant Converter with Three Half-Bridge Legs for Wide Voltage Operation

2019 ◽  
Vol 10 (1) ◽  
pp. 310 ◽  
Author(s):  
Bor-Ren Lin ◽  
Yong-Sheng Zhuang
Keyword(s):  
Power Conversion ◽  
Input Voltage ◽  
Resonant Circuit ◽  
Resonant Converters ◽  
Resonant Converter ◽  
High Input ◽  
Switching Operation ◽  
Voltage Range ◽  
Dc Power ◽  
Power Switches

This paper studied a hybrid resonant converter with three half bridge legs for wide input voltage operation. Compared to the conventional resonant converters with narrow voltage operation, the presented converter can achieve wider voltage operation. On the basis of the proper switching status of power switches, the developed converter can operate at half-bridge resonant circuit under high input voltage range and the other two full-bridge resonant circuits under medium and low input voltage ranges. Each resonant circuit has a 2:1 (Vin,max = 2Vin,min) input voltage operation range. Therefore, the developed converter can achieve an 8:1 (Vin,max = 8Vin,min) wide voltage operation. The main advantage of the studied converter is the single-stage direct current (DC)/DC power conversion instead of the two-stage power conversion to achieve wide voltage operation. Because the equivalent resonant tank of the adopted converter is controlled by frequency modulation, the soft switching operation on power switches or rectifier diodes can be realized to improve circuit efficiency. The performance of the proposed circuit was confirmed and verified by experiments with a laboratory circuit.

scholarly journals Comparative Performance and Assessment Study of a Current-Fed DC-DC Resonant Converter Combining Si, SiC, and GaN-Based Power Semiconductor Devices

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1982
Author(s):  
Oscar Miguel Rodríguez-Benítez ◽  
Mario Ponce-Silva ◽  
Juan Antonio Aquí-Tapia ◽  
Abraham Claudio-Sánchez ◽  
Luis Gerardo Vela-Váldes ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Input Voltage ◽  
Oxide Semiconductor ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Comparative Performance ◽  
Voltage Range ◽  
Power Semiconductor ◽  
Low Efficiency ◽  
A Current

This paper focuses on the main reasons of low efficiency in a current-fed DC-DC resonant converter applied to photovoltaic (PV) isolated systems, comparing the effects derived by the overlapping time in the gate-signals (gate-source voltage) combining silicon (Si), silicon carbide (SiC), and gallium nitride (GaN)-based power devices. The results show that unidirectional switches (metal–oxide–semiconductor field-effect transistors (MOSFETs) plus diode) present hard switching as a result of the diode preventing the MOSFET capacitance of being discharged. The effectiveness of the converter was verified with a 200-W prototype with an input voltage range of 0–30.3 V, an output voltage of 200 V, and a switching frequency of 200 kHz. The reduction losses by applying GaN versus Si and SiC technologies are 66.49% and 53.57%, respectively. Alternatively, by applying SiC versus Si devices the reduction loss is 27.84%. Finally, according to the results, 60% of losses were caused by the diodes on both switches.

scholarly journals Pulse Width and Frequency Hybrid Modulated LLC Converter Adapted to Ultra Wide Voltage Range

Inventions ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 77 ◽  
Author(s):  
Umar Khalid ◽  
Muhammad Mansoor Khan ◽  
Muhammad Zahid Khan ◽  
Muhammad Ahmad Usman Rasool ◽  
Jianming Xu
Keyword(s):  
Pulse Width ◽  
Power Flow ◽  
Modulation Method ◽  
Switching Frequency ◽  
Circuit Modeling ◽  
Resonant Converter ◽  
Peak Efficiency ◽  
Voltage Range ◽  
Llc Resonant Converter ◽  
Efficient Power

In wide voltage range applications such as electric vehicles (EVs) onboard charging, conventional frequency modulated LLC topology has its intrinsic limitations. Its frequency span is extremely wide and the soft switching feature might get lost. To address this issue, this paper proposes a novel LLC resonant converter. The pulse width and frequency hybrid modulation are adopted to narrow down its switching frequency span. The operating principles, circuit modeling, and the design methodology are presented. A 1 kW rated prototype has been built to realize an efficient power flow between the 400 V DC bus and 200–440 V battery pack. The designed prototype validates the effectiveness of the proposed topology and modulation method. 96.8% peak efficiency is measured for the constructed experimental prototype.

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