scholarly journals Extending the Input Voltage Range of Solar PV Inverters with Supercapacitor Energy Circulation

Electronics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 88
Author(s):  
Kosala Gunawardane ◽  
Nalin Bandara ◽  
Kasun Subasinghage ◽  
Nihal Kularatna
Keyword(s):  
Input Voltage ◽  
Limited Attention ◽  
Solar Pv ◽  
Distributed Energy ◽  
Voltage Range ◽  
Grid Systems ◽  
Dc Line ◽  
Technical Specifications ◽  
Input Range ◽  
Frequency Inverter

Cleaner and greener energy sources have proliferated on a worldwide basis, creating distributed energy systems. Given the unreliable nature of the renewable sources such as solar and wind, they are traditionally based on inverters interfaced with legacy AC grid systems. While efficiency, output waveform quality and other technical specifications of inverters keep improving gradually, only limited attention is given to widening the input range of inverters. This paper presents a new supercapacitor assisted (SCA) technique to widen the input range of an inverter without modifying the inverter itself. Developing a prototype version of a 24 V DC input capable supercapacitor-assisted wide input (SCASWI) inverter using a supercapacitor circulation front end and a commercial 12 V DC line frequency inverter is detailed in the article, explaining how the SCASWI inverter technique doubles the input voltage while maintaining the useful characteristics of the commercial inverter. The new technique has the added advantage of DC-UPS capability based on a long-life supercapacitor module.

Design Technique of High Power Efficiency LLC DC-DC Converters for Photovoltaic Cells

2018 ◽  
Vol 2 (1) ◽  
pp. 30
Author(s):  
Hisatsugu Kato ◽  
Yoichi Ishizuka ◽  
Kohei Ueda ◽  
Shotaro Karasuyama ◽  
Atsushi Ogasahara
Keyword(s):  
High Power ◽  
Power Efficiency ◽  
Photovoltaic Cells ◽  
Input Voltage ◽  
Design Technique ◽  
Load Range ◽  
Voltage Range ◽  
Simulation Results ◽  
Secondary Side ◽  
High Power Efficiency

This paper proposes a design technique of high power efficiency LLC DC-DC Converters for Photovoltaic Cells. The secondary side circuit and transformer fabrication of proposed circuit are optimized for overcoming the disadvantage of limited input voltage range and, realizing high power efficiency over a wide load range of LLC DC-DC converters. The optimized technique is described with theoretically and with simulation results. Some experimental results have been obtained with the prototype circuit designed for the 80 - 400 V input voltage range. The maximum power efficiency is 98 %.

scholarly journals Quantification of PV Power and Economic Losses Due to Soiling in Qatar

2021 ◽  
Vol 13 (6) ◽  
pp. 3364
Author(s):  
Amr Zeedan ◽  
Abdulaziz Barakeh ◽  
Khaled Al-Fakhroo ◽  
Farid Touati ◽  
Antonio S. P. Gonzales
Keyword(s):  
Output Power ◽  
Power Plants ◽  
Economic Loss ◽  
Economic Losses ◽  
Energy Yield ◽  
Solar Pv ◽  
Financial Loss ◽  
Grid Systems ◽  
Dust Density

Soiling losses of photovoltaic (PV) panels due to dust lead to a significant decrease in solar energy yield and result in economic losses; this hence poses critical challenges to the viability of PV in smart grid systems. In this paper, these losses are quantified under Qatar’s harsh environment. This quantification is based on experimental data from long-term measurements of various climatic parameters and the output power of PV panels located in Qatar University’s Solar facility in Doha, Qatar, using a customized measurement and monitoring setup. A data processing algorithm was deliberately developed and applied, which aimed to correlate output power to ambient dust density in the vicinity of PV panels. It was found that, without cleaning, soiling reduced the output power by 43% after six months of exposure to an average ambient dust density of 0.7 mg/m3. The power and economic loss that would result from this power reduction for Qatar’s ongoing solar PV projects has also been estimated. For example, for the Al-Kharasaah project power plant, similar soiling loss would result in about a 10% power decrease after six months for typical ranges of dust density in Qatar’s environment; this, in turn, would result in an 11,000 QAR/h financial loss. This would pose a pressing need to mitigate soiling effects in PV power plants.

scholarly journals Centralized vs. distributed energy storage systems: The case of residential solar PV-battery

Energy ◽  
2021 ◽  
pp. 121443
Author(s):  
Behnam Zakeri ◽  
Giorgio Castagneto Gissey ◽  
Paul E. Dodds ◽  
Dina Subkhankulova
Keyword(s):  
Energy Storage ◽  
Storage Systems ◽  
Solar Pv ◽  
Distributed Energy ◽  
Energy Storage Systems ◽  
Distributed Energy Storage

scholarly journals Hybrid DC-DC Converter with Low Switching Loss, Low Primary Current and Wide Voltage Operation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2536
Author(s):  
Bor-Ren Lin ◽  
Yi-Kuan Lin
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Input Voltage ◽  
Resonant Circuit ◽  
Switching Loss ◽  
Voltage Range ◽  
Current Loss ◽  
Zero Voltage Switching ◽  
Energy Applications ◽  
Multi Stage

A full-bridge converter with an additional resonant circuit and variable secondary turns is presented and achieved to have soft-switching operation on active devices, wide voltage input operation and low freewheeling current loss. The resonant tank is linked to the lagging-leg of the full bridge pulse-width modulation converter to realize zero-voltage switching (ZVS) characteristic on the power switches. Therefore, the wide ZVS operation can be accomplished in the presented circuit over the whole input voltage range and output load. To overcome the wide voltage variation on renewable energy applications such as DC wind power and solar power conversion, two winding sets are used on the output-side of the proposed converter to obtain the different voltage gains. Therefore, the wide voltage input from 90 to 450 V (Vin,max = 5Vin,min) is implemented in the presented circuit. To further improve the freewheeling current loss issue in the conventional phase-shift pulse-width modulation converter, an auxiliary DC voltage generated from the resonant circuit is adopted to reduce this freewheeling current loss. Compared to the multi-stage DC converters with wide input voltage range operation, the proposed circuit has a low freewheeling current loss, low switching loss and a simple control algorithm. The studied circuit is tested and the experimental results are demonstrated to testify the performance of the resented circuit.

scholarly journals Risk-Averse Scheduling of Combined Heat and Power-Based Microgrids in Presence of Uncertain Distributed Energy Resources

2021 ◽  
Vol 13 (13) ◽  
pp. 7119
Author(s):  
Abbas Rabiee ◽  
Ali Abdali ◽  
Seyed Masoud Mohseni-Bonab ◽  
Mohsen Hazrati
Keyword(s):  
Electrical Energy ◽  
High Energy ◽  
Combined Heat And Power ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Solar Pv ◽  
Distributed Energy ◽  
Robust Scheduling ◽  
Battery Energy ◽  
The Impact

In this paper, a robust scheduling model is proposed for combined heat and power (CHP)-based microgrids using information gap decision theory (IGDT). The microgrid under study consists of conventional power generation as well as boiler units, fuel cells, CHPs, wind turbines, solar PVs, heat storage units, and battery energy storage systems (BESS) as the set of distributed energy resources (DERs). Additionally, a demand response program (DRP) model is considered which has a successful performance in the microgrid hourly scheduling. One of the goals of CHP-based microgrid scheduling is to provide both thermal and electrical energy demands of the consumers. Additionally, the other objective is to benefit from the revenues obtained by selling the surplus electricity to the main grid during the high energy price intervals or purchasing it from the grid when the price of electricity is low at the electric market. Hence, in this paper, a robust scheduling approach is developed with the aim of maximizing the total profit of different energy suppliers in the entire scheduling horizon. The employed IGDT technique aims to handle the impact of uncertainties in the power output of wind and solar PV units on the overall profit.

scholarly journals Analysis of a Wide Voltage Hybrid Soft Switching Converter

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 473 ◽  
Author(s):  
Bor-Ren Lin ◽  
Yen-Chun Liu
Keyword(s):  
Power Conversion ◽  
Input Voltage ◽  
Soft Switching ◽  
Resonant Converter ◽  
Solar Pv ◽  
Load Range ◽  
Pwm Converter ◽  
Load Voltage ◽  
Zero Voltage Switching ◽  
Circulating Current

A hybrid PWM converter is proposed and investigated to realize the benefits of wide zero-voltage switching (ZVS) operation, wide voltage input operation, and low circulating current for direct current (DC) wind power conversion and solar PV power conversion applications. Compared to the drawbacks of high freewheeling current and hard switching operation of active devices at the lagging-leg of conventional full bridge PWM converter, a three-leg PWM converter is studied to have wide input-voltage operation (120–600 V). For low input-voltage condition (120–270 V), two-leg full bridge converter with lower transformer turns ratio is activated to control load voltage. For high input-voltage case (270–600 V), PWM converter with higher transformer turns ratio is operated to regulate load voltage. The LLC resonant converter is connecting to the lagging-leg switches in order to achieve wide load range of soft switching turn-on operation. The high conduction losses at the freewheeling state on conventional full bridge converter are overcome by connecting the output voltage of resonant converter to the output rectified terminal of full bridge converter. Hence, a 5:1 (600–120 V) hybrid converter is realized to have less circulating current loss, wide input-voltage operation and wide soft switching characteristics. An 800 W prototype is set up and tested to validate the converter effectiveness.

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