Leakage Magnetic Field Suppression Using Dual-Transmitter Topology in EV Wireless Charging

Zhu, Guodong,Gao, Dawei,Lin, Shulin The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3

This paper proposes an active leakage magnetic field (LMF) suppression scheme, which uses the dual-transmitter (DT) topology, for EV wireless charging systems (EVWCS). The two transmitter coils are coplanar, concentric and driven by separate inverters. The LMF components generated by the three coils cancel each other out to reduce the total field strength. This paper gives a detailed theoretical analysis on the operating principles of the proposed scheme. Finite element analysis is used to simulate the LMF distribution patterns. Experimental results show that when there is no coil misalignment, 97% of the LMF strength can be suppressed in a 1kW prototype. These results also show that the impact on efficiency is small. The trade-off between LMF suppression and efficiency is revealed, and a control strategy to balance these two objectives is presented.

Effects of high-temperature stress and heat shock on two root maggots, Bradysia odoriphaga and Bradysia difformis (Diptera: Sciaridae)

Guodong Zhu,Yin Luo,Ming Xue,Haipeng Zhao,NanNan Xia,Xinhui Wang 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.1

Bradysia odoriphaga and B. difformis (Diptera: Sciaridae) are devastating pests of vegetables, ornamentals andedible mushrooms. In Chinese chive fields, the two Bradysia species occur with similar regularities: outbreaks inspring and autumn, and population decreases in summer. Temperature may be an important factor restrictingtheir population abundance in summer. Here, we performed a life-table study under constant high temperaturesand assessed the tolerance of two Bradysia species to heat shock. Life parameters of the Bradysia species indicatedslow developmental rates, and low survival rates and fecundity, when the temperature was higher than 30 °C. At34 °C, individuals were unable to reach the adult stages from eggs. Moreover, temperatures above 36 °C showedlethal effects, decreasing their survival rates. The median lethal time (LT50) values of 4th instar B. odoriphagaand B. difformis larvae were 46.82 and 32.97 h, respectively, while the values at 38 °C were 2.12 and 1.51 h,respectively. The 4th instar larvae and pupae possessed higher thermotolerance levels than adults and eggs,indicating sensitivities to heat stress. Moreover, B. odoriphaga was more thermotolerant than B. difformis. Thus,weak thermotolerance levels may restrict their occurrences during the period of summer heat, and the differencein thermotolerance levels between the two species may be related to their regional distributions.

Effects of colored polyethylene film mulch on pest populations, plant growth and yield of peanut in Northern China

Zhu Guodong,Xia Nannan,Xue Ming,Li Zhaopeng,Zhao Haipeng,Qu Cheng 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.3

Polyethylene film mulching is commonly used in peanut (Arachis hypogaea L.) production, an important oil crop. Clear polyethylene film (CLEF) has previously been the only choice for all growing conditions. However, colored polyethylene film has been applied to the cultivation of crops in recent years, so testing the effects of colored film mulches on peanuts is necessary. In this study, we observed the effects of eight colored polyethylene films on devastating pest abundance, plant growth and yield, and soil conditions in peanut fields. The results showed that light-silver-gray film (LSGF), silver-black on both sides film (SGBF), and black film (BLAF) mulches were more effective in reducing the pest population (aphids, thrips, and mites) compared to plants mulched with other films. In addition, SGBF and LSGF mulching accelerated seeding emergence and benefited peanut growth, and the yield increased by about 20% compared to peanuts mulched with CLEF. The soil temperature and humidity under the LSGF and SGBF treatment were more suitable for peanut growth compared to the other film treatments. In conclusion, LSGF and SGBF mulches were appropriate choices for managing pests, maintaining optimum soil conditions, and increasing yield in peanut production.

Highly effective leakage magnetic field suppression by using a reactive coil in perfectly aligned EV wireless charging systems

Zhu, Guodong,Gao, Dawei The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.1

Using a reactive coil to suppress the leakage magnetic field (LMF) in wireless power transfer is practical, but the suppression capability reported in the literature is still limited. This paper proposes several methods for improving the suppression capability of this scheme. Three conditions are required to realize this goal, namely (1) a good LMF proportionality, (2) an equation regarding the LMF coefficients and mutual inductances, and (3) an equation regarding the impedance of the reactive coil loop. Coil geometry optimization is performed to meet condition (2), and coil reactance is compensated by a capacitor to meet condition (3). Given the trade-off between LMF suppression capability and efficiency, a control strategy based on a switching capacitor array is adopted. In the experiments, a 97.5% reduction in the LMF strength is achieved on the measurement point with slight effects on efficiency.

Leakage Magnetic Field Suppression Using Dual-Transmitter Topology in EV Wireless Charging

Guodong Zhu,Dawei Gao,Shulin Lin 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3

This paper proposes an active leakage magnetic field (LMF) suppression scheme, which uses the dual-transmitter (DT) topology, for EV wireless charging systems (EVWCS). The two transmitter coils are coplanar, concentric and driven by separate inverters. The LMF components generated by the three coils cancel each other out to reduce the total field strength. This paper gives a detailed theoretical analysis on the operating principles of the proposed scheme. Finite element analysis is used to simulate the LMF distribution patterns. Experimental results show that when there is no coil misalignment, 97% of the LMF strength can be suppressed in a 1kW prototype. These results also show that the impact on efficiency is small. The trade-off between LMF suppression and efficiency is revealed, and a control strategy to balance these two objectives is presented.

Parameter Optimization of the LC filters Based on Multiple Impact Factors for Cascaded H-bridge Dynamic Voltage Restorers

Guodong Chen,Miao Zhu,Xu Cai 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1

The cascaded H-Bridge Dynamic Voltage Restorer (DVR) is used for protecting high voltage and large capacity loads from voltage sags. The LC filter in the DVR is needed to eliminate switching ripples, which also provides an accurate tracking feature in a certain frequency range. Therefore, the parameter optimization of the LC filter is especially important. In this paper, the value range functions for the inductance and capacitance in LC filters are discussed. Then, parameter variations under different conditions of voltage sags and power factors are analyzed. In addition, an optimized design method is also proposed with the consideration of multiple impact factors. A detailed optimization procedure is presented, and its validity is demonstrated by simulation and experimental results. Both results show that the proposed method can improve the LC filter design for a cascaded H-Bridge DVR and enhance the performance of the whole system.

Parameter Optimization of the LC filters Based on Multiple Impact Factors for Cascaded H-bridge Dynamic Voltage Restorers

Chen, Guodong,Zhu, Miao,Cai, Xu The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1

The cascaded H-Bridge Dynamic Voltage Restorer (DVR) is used for protecting high voltage and large capacity loads from voltage sags. The LC filter in the DVR is needed to eliminate switching ripples, which also provides an accurate tracking feature in a certain frequency range. Therefore, the parameter optimization of the LC filter is especially important. In this paper, the value range functions for the inductance and capacitance in LC filters are discussed. Then, parameter variations under different conditions of voltage sags and power factors are analyzed. In addition, an optimized design method is also proposed with the consideration of multiple impact factors. A detailed optimization procedure is presented, and its validity is demonstrated by simulation and experimental results. Both results show that the proposed method can improve the LC filter design for a cascaded H-Bridge DVR and enhance the performance of the whole system.

Controllable synthesis of bowl-shaped porous carbon materials through didodecyldimethylammonium bromide for high performance supercapacitors

Guo Qiang Zhu,Li Bingyu,Shen Ming,Li Weizheng,Gao Qiang,Xu Guodong 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.6

A series of bowl-shaped porous carbon materials was successfully synthesized by the use of didodecyldimethylammonium bromide as the soft template agent. By controlling the dosage of the soft template agent and the water/ethanol ratio of the solvent, the size and structure of the carbon materials can be precisely controlled. The prepared carbon materials with stacked bowl structure have good specific surface area (1,380.20 m2 g−1), large pore volume (1.27 cm3 g−1) and high heteroatom N doping amount (6.68 at.%). Moreover, electrochemical tests in 6 M KOH demonstrated impressive electrochemical performance, where the specific capacity of the typical materials was measured to be 191.0 F g−1 (at the current density of 1 A g−1), and the capacity retention rate of typical materials was 80% (at the current density of 10 A g−1).

Effect of cohesive powders on pressure fluctuation characteristics of a binary gas-solid fluidized bed

Liping Wei,Youjun Lu,Jianbo Zhu,Guodong Jiang,Jun Hu,Haipeng Teng 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.10

The effect of cohesive particles on the pressure fluctuations was experimentally investigated in a binary gassolid fluidized bed. The pressure fluctuation signals were measured by differential pressure sensors under conditions of various weight percentages of cohesive particles. The cohesive particles increased the fixed bed pressure drop per unit height and decreased the minimum fluidization velocity. The Wen & Yu equation well predicts the minimum fluidization velocity of the binary system. The addition of cohesive particles slightly decreased the bubble size in bubbling flow regime when the cohesive particles and the coarse particles mixed well, while the bubble size greatly decreased when the cohesive particles agglomerated on the bed surface. The time series of pressure fluctuations was analyzed by using the methods of time domain, frequency domain and wavelet transformation. The normalized standard deviation of pressure fluctuations decreased with increasing weight percentages of cohesive particles. A wide bandwidth frequency of 0 to 1Hz got narrower with a single peak around 0.6Hz with an increase in proportion of the cohesive particles. The meso-energy and micro-energy of pressure fluctuations were decreasing with increasing cohesive particles proportions, which indicated that adding cohesive particles could reduce the energy dissipation of bubble and particle fluctuations.

Application of Optimized GM (1, 1) Prediction Model based on Ant Colony Algorithm in the Medium and Long Term Load Forecasting

JunSong Qin,Yan Lu,Dongxiao Niu,Guodong Zhu 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.8

The medium and long term load forecasting is the basis of power planning, investment, production, scheduling and trade, which plays an important role in electric power safety and economic operation. In China, it has the increasing uncertainty and the uncertainty of random variation to forecast the medium and long term load. Thus we can regard it as a typical grey system. However, the traditional grey prediction method cannot be adapt to the needs of the load forecasting gradually. It need to be rich and perfect with the continuous improvement of power system complexity and power marketization degree. This paper studied the modelling mechanism of grey prediction model. Then we analyzed the problems existing in the model, including the boundary value problem, the background value structure problem and the least squares parameter identification problem. This paper put forward an optimization method to directly identify the boundary value x(0)(1), the developing coefficient a and grey coefficient b using ant colony algorithm according to the time response expression of GM(1,1) model, so that it established an optimized GM(1,1) prediction model based on ant colony algorithm. This model can fix the impact of boundary value, and also avoid the errors brought by the background value construction and the least squares parameter estimation. It can verify the effectiveness of the proposed optimization model through the load data simulation. And it can improve the prediction accuracy effectively.