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LLC Resonant Voltage Multiplier-Based Differential Power Processing Converter Using Voltage Divider with Reduced Voltage Stress for Series-Connected Photovoltaic Panels under Partial Shading
摘要： Partial shading on photovoltaic (PV) strings consisting of multiple panels connected in series is known to trigger severe issues, such as reduced energy yield and the occurrence of multiple power point maxima. Various kinds of differential power processing (DPP) converters have been proposed and developed to prevent partial shading issues. Voltage stresses of switches and capacitors in conventional DPP converters, however, are prone to soar with the number of panels connected in series, likely resulting in impaired converter performance and increased circuit volume. This paper proposes a DPP converter using an LLC resonant voltage multiplier (VM) with a voltage divider (VD) to reduce voltage stresses of switches and capacitors. The VD can be arbitrarily extended by adding switches and capacitors, and the voltage stresses can be further reduced by extending the VD. Experimental verification tests for four PV panels connected in series were performed emulating partial shading conditions in a laboratory and outdoor. The results demonstrated the proposed DPP converter successfully precluded the negative impacts of partial shading with mitigating the voltage stress issues.
关键词： LLC converter,differential power processing converter,voltage multiplier,voltage divider,photovoltaic system,partial shading
更新于2025-09-16 10:30:52
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A Compact Wireless Power Transfer System at 915 MHz with Supercapacitor for Optogenetics Applications
摘要： To facilitate sophisticated optogenetics research with minimal disruption to animal’s behavior, a fully wireless optical stimulator module is desirable. This paper presents a compact wireless power transfer (WPT) system for optogenetics applications that is adapted to work in implanted condition with unstable and insufficient ambient RF energy field. The scope of this work is to design and implement a power transfer system architecture that is able to: 1) work over long distance, 2) achieve high power conversion efficiency and 3) provide stable output power for sufficient time duration. The designed WPT circuit operates at 915 MHz and achieves maximum power conversion efficiency of 50% at -15 dBm input power. With a compact circuitry design (12.20 × 13.22 mm), the obtained full power transmission efficiency was 0.329 % at 20 dBm (100 mW) transmission power. Ex-vivo experiments indicated that when the WPT system was located 10 cm from the source, it retrieved a maximum of 0.324 mW in free space, and 0.112 mW if inserted inside porcine cadaver meat with 4 cm of thickness. At a distance of 1 m from the source, the system retrieved 17 μW in free space, and 1 μW in porcine meat. Furthermore, to sufficiently drive the LED, an advanced supercapacitor was utilized as an energy storage element. When fully charged, the system can supply the LED over 75 seconds with a total power of 2.45 W. The developed WPT system can be a viable solution to be applied in optogenetic experiments on laboratory animals for preclinical studies.
关键词： Optogenetics,Bioimplantable,Wireless power transfer,Voltage multiplier,Supercapacitor
更新于2025-09-10 09:29:36
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Enhanced Dickson voltage multiplier rectenna by developing analytical model for radio frequency harvesting applications
摘要： Radio frequency (RF) energy harvesting has experienced a rapid development recently because of the increasing number of RF transmitter sources. This article illustrates a novel analytical model for the voltage multiplier rectifier at 900 MHz. The model proposes a method of deriving the output characteristics of the rectifying circuits in terms of two main parameters; voltage and current. The design consists of seven stages of Dickson voltage multiplier rectifier. A Schottky diode HSMS 285C was used in the design. Equations for the model were developed. These equations were used to extract the values of output voltage and current. A simulation was optimized using advanced design systems. The system was correspondingly fabricated and tested for input power range of 1 × 10?5-1 × 10?1 W. Experimental results show that an output voltage of 5.45 V and current of 1.26 × 10?5 A are achieved at 10 dBm using a 10 kΩ load, achieving an efficiency of 37.82%.
关键词： analytical model,Dickson voltage multiplier rectifier,RF harvesting,rectenna
更新于2025-09-04 15:30:14