A novel single-layer winding array and receiver coil structure for contactless battery charging systems with free-positioning and localized charging features

The planar contactless battery charging system is an emerging technology that can be applied to a wide range of portable consumer electronic products. Beginning with a brief historical background, this paper presents a new single-layer winding array and receiver coil structure with cylindrical ferrite cores for planar contactless battery charging systems. Complying with the Qi standard, this design enables multiple devices to be placed and charged simultaneously on the wireless charging pad in a free-positioning manner. The charging flux is totally localized within the covered area between the selected primary winding and the secondary winding inside the load. The electromagnetic characteristics of such winding design are studied in finite-element analysis and confirmed by practical implementation. © 2010 IEEE.published_or_final_versionlink_to_subscribed_fulltex

Effects of magnetic coupling of nonadjacent resonators on wireless power domino-resonator systems

In this paper, the effects of the magnetic coupling of nonadjacent resonators on the optimal frequency of wireless power transfer are addressed. A power analysis has been carried out to identify the adjacent and nonadjacent power flow components. It is found that such cross-coupling effects of nonadjacent resonators would cause the maximum efficiency operation to slightly shift away from the resonance frequency of the resonators. Theoretical reasons for such phenomena are provided and experimentally confirmed with practical measurements in a wireless power transfer system comprising several magnetically coupled resonators arranged in a straight domino form. © 2011 IEEE.published_or_final_versio

Using self-driven AC-DC synchronous rectifier as a direct replacement for traditional power diode rectifier

Synchronous rectification has previously been adopted in switched-mode circuits for reducing the conduction losses particularly in high-frequency, low-voltage, and high-current applications. This paper presents a generalized self-driven ac-dc synchronous rectification technique that can be used even at mains frequency to develop an ac-dc synchronous rectifier that behaves like a diode bridge but with much reduced conduction losses and without control integrated circuits. This generalized concept can be extended from single-phase to multiphase systems. Experiments based on 1- and 2-kW single-phase systems have been successfully conducted for capacitive, inductive, and resistive loads. Very significant power loss reduction (over 50%) has been achieved in the rectification stage at both 110- and 220-V ac mains operations. This patent-pending circuit can be regarded as a direct replacement of a general-purpose diode rectifier. Due to the reduction of power loss, further reduction in the size and cost of the heat sink or thermal management for the power circuit becomes possible. © 2011 IEEE.published_or_final_versio

Novel self-configurable current-mirror techniques for reducing current imbalance in parallel Light-Emitting Diode (LED) strings

Traditional current-mirror methods require one fixed current reference for controlling other current source or sources. In this paper, a new self-configurable current-mirror method that can dynamically determine the best current branch as the current reference in order to ensure good balance of all parallel current sources is proposed. The operating principle involves a dynamic and self-configurable transistor-based current-balancing circuit that can be operated in saturation or linear mode. In either operating mode, good current balance or sharing among all parallel-connected current sources can be guaranteed. The novel current-balancing circuit does not require a separate power supply for powering their control circuits. The proposal is a modular one that can be expanded to any number of parallel current sources. Its principle has been successfully applied to current balancing of parallel LED strings. © 2011 IEEE.published_or_final_versio

Generalized self-driven AC-DC synchronous rectification techniques for single- and multiphase systems

This paper extends the single-phase self-driven synchronous rectification (SDSR) technique to multiphase ac-dc systems. Power MOSFETs with either voltage- or current-sensing self-driven gate drives are used to replace the diodes in the rectifier circuits. The generalized methodology allows multiphase SDSRs to be designed to replace the multiphase diode rectifiers. Unlike the traditional SR that is designed for high-frequency power converters, the SDSR proposed here can be a direct replacement of the power diode bridges for both low- and high-frequency operations. The SDSR utilizes its output dc voltage to supply power to its control circuit. No start-up control is needed because the body diodes of the power MOSFETs provide the diode rectifier for the initial start-up stage. The generalized method is demonstrated in 2-kW one-phase and three-phase SDSRs for inductive, capacitive, and resistive loads. Power loss reduction in the range of 50%-69% has been achieved for the resistive load. © 2009 IEEE.published_or_final_versio

Maximum energy efficiency tracking for wireless power transfer systems

A method for automatic “maximum energy efficiency tracking” operation for wireless power transfer (WPT) systems is presented in this paper. Using the switched-mode converter in the receiver module to emulate the optimal load value, the proposed method follows the maximum energy efficiency operating points of a WPT system by searching for the minimum input power operating point for a given output power. Because the searching process is carried out on the transmitter side, the proposal does not require any wireless communication feedback from the receiver side. The control scheme has been successfully demonstrated in a two-coil system under both weak and strong magnetic coupling conditions. Experimental results are included to confirm its feasibility

Niches and Interspecific Competitive Relationships of the Parasitoids, Microplitis prodeniae and Campoletis chlorldeae, of the Oriental Leafworm Moth, Spodoptera litura, in Tobacco

Both Microplitis prodeniae Rao and Chandry (Hymenoptera: Bracondidae) and Campoletis chlorideae Uchida (Hymenoptera: Ichnumonidae) are major parasitoids of Spodoptera litura (Fabricious) (Lepidoptera: Noctuidae) in tobacco, Nicotiana tabacum L. (Solanales: Solanaceae) at Nanxiong, Guangdong Province, South China. The niches and interspecific competition relationships of the two species were studied. The results show that the competition between the two species for spatial and food resources was very intense, and C. chlorideae was always dominant when the two species compete for spatial and food resources in different periods. Thus C. chlorideae may drive M. prodeniae away when they occupy the same spatial or food resource. The adaptability of C. chlorideae to the environment in the tobacco fields may be greater than that of M. prodeniae, so C. chlorideae can maintain a higher population compared to that of M. prodeniae

Acupoint Autohemotherapy Attenuates DNCB-Induced Atopic Dermatitis and Activates Regulatory T Cells in BALB/c Mice

Shi-Hua Yan,1,2 Yong Chen,3 Zhi-Qian Huang,1 Wen-Xi Zhong,1 Xiao-Tian Wang,1 Yang-Can Tang,1 Xu-Yi Zhao,1 Yu-Shan Wu,1 Chun Zhou,4 Wei Zhu,5 Wei Xiao,1,6 Xuan Li,2 Dong-Shu Zhang1,2 1School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, People’s Republic of China; 2Department of Traditional Chinese Medicine, The Tenth affiliated Hospital, Southern Medical University (Dongguan People’s Hospital), Dongguan, Guangdong, 523058, People’s Republic of China; 3Department of Rheumatology and Immunology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, 563000, People’s Republic of China; 4School of Pharmaceutical Sciences; Guangdong Provincial Key Laboratory of Shock and Microcirculation, Southern Medical University, Guangzhou, Guangdong, 510515, People’s Republic of China; 5Guangzhou Center for Disease Control and Prevention, Guangzhou, 510440, People’s Republic of China; 6Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education, Guangdong Pharmaceutical University, Guangzhou, Guangdong, 510006, People’s Republic of ChinaCorrespondence: Dong-Shu Zhang, School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, People’s Republic of China, Email [email protected] Wei Xiao, Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education, Guangdong Pharmaceutical University, Guangzhou, Guangdong, 510006, People’s Republic of China, Email [email protected]: Acupoint autohemotherapy (A-AHT) has been proposed as an alternative and complementary treatment for atopic dermatitis (AD), yet the exact role of its blood component in terms of therapeutic efficacy and mechanism of action is still largely unknown.Methods: This study aimed to evaluate the therapeutic efficacies and action mechanisms of intramuscular injections of autologous whole blood (AWB) and mouse immunoglobulin G (IgG) (autologous or heterologous) at acupoints on 2,4-dinitrochlorobenzene (DNCB)-induced AD mouse models. Serum levels of total immunoglobulin E (IgE), IgG, interleukin-10 (IL-10), and interferon-gamma (IFN-γ) were measured, as well as mRNA expression levels of Forkhead box P3 (FoxP3), IL-10 and IFN-γ in dorsal skin lesions, and IL-10+, IFN-γ+ and FoxP3+CD4+T cells in murine spleen.Results: It showed that repeated acupoint injection of AWB, autologous total IgG (purified from autologous blood in AD mice) or heterologous total IgG (purified from healthy blood in normal mice) effectively reduced the severity of AD symptoms and decreased epidermal and dermal thickness as well as mast cells in skin lesions. Additionally, AWB acupoint injection was found to upregulate FoxP3+, IL-10+ and IFN-γ+ CD4+T cells in murine spleen, suppressing the production of IgE antibodies and increasing that of IgG antibodies in the serum. Furthermore, both AWB and autologous total IgG administrations significantly elevated FoxP3 expression, mRNA levels of IL-10 and IFN-γ in dorsal skin lesions. However, acupoint injection of heterologous total IgG had no effect on regulatory T (Treg) and Th1 cells modulation.Conclusion: These findings suggest that the therapeutic effects of A-AHT on AD are mediated by IgG-induced activation of Treg cells.Keywords: autologous whole blood, acupoint injection, atopic dermatitis, anti-idiotypic immunomodulation, Treg