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Model of magnetic coupling WPT (a) mutual model based on reflective impedance, (b) model of transformer with complex transformation ratio
Source publication
Many applications of wireless power transmission (WPT) require high misalignment tolerance. However, the transmission power of WPT is highly susceptible to the misalignment. To solve this problem, the magnetic resonant WPT control method with high misalignment tolerance is proposed here. First, based on the general mutual model, the complex ratio t...
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When the coils of wireless power transmission system based on a traditional topology is physically offset, the coupling coefficient between the coils will change significantly, which further leads to drastic changes in the output power of the system. This problem limits the application and promotion of wireless power transmission. In order to solve...
In order to solve the problem that the magnetic coupling resonant WPT system with SS compensation structure causes a decrease in transmission efficiency when it is detuned, the resonant state of the system is tracked by detecting the output voltage of the transmitting coil inverter and the coil current of the receiving coil. Phase difference is con...
Citations
... With highways electrified to provide wireless charging, it will lay the groundwork for mass-market adoption of electric vehicles, regardless of battery technology [19,20]. Researchers have conducted more research on topology [21], control [22][23][24], inverter design [25][26][27], and human safety [28][29][30][31]. ...
Wireless charging modules for electric vehicles are being increasingly studied. Previous
research has focused on developing more effective wireless-charging modules for electric vehicles in
order to pave the way for a more sustainable urban transportation. The objectives of the study were
to identify the social structure of the field by mapping of research collaborations among authors and
countries, measure the influence of authors and sources, identify the interactions between different
researchers and the most influential authors, sources, documents and organizations. To achieve
these objectives, a bibliometric search in the SCOPUS database was conducted using a combination
of keywords and Boolean operators. The initial keyword search returned 2163 documents. The
documents retrieved were manually filtered for further analysis. A scientometric analysis was
carried out on the remaining 1367 documents using co-authorship, co-citation, and citation analyses
for a number of measurement units. The results showed that “object detection” and “shielding
effectiveness” were the most current research topics. Authors who were widely cited did not generally
produce a large number of papers or collaborate with other authors. Authors from China, the United
States, and the United Kingdom have all co-authored published works on the topic, indicating that
they have all contributed considerably to the field’s achievements. This strongly highlighted the
amount of funding localized in developed countries towards such technologies. The number of
international co-authored studies conducted was low. This is most significant with no research
conducted in this field in the less developed world. The most cited and influential scholars were G. A.
Covic, J. T. Boys, and C. C. Mi. The most influential sources were IEEE Trans. on Power Electronics and
IEEE Trans. on Induction Electronics, while the most productive sources were Energies and IEEE Access.
The most influential documents were those by Covic G.A. (2013a) and Covic G.A. (2013b). Finally,
emerging trends in charging and energy storage in electric vehicles were also discussed.
... And many efforts have been contributed to it. The authors in [4][5][6] proposed the frequency control method, which is to regulate the power transferred via adjusting the resonant operating frequency. The structure of the multi-transmitter can also regulate the power transferred [7][8][9][10][11][12]. ...
... Taking the derivative of D in (4) with making it equal to zero, (5)is derived. However, as the range of duty cycle is 0 < D < 1, hence the root of (5) is unique and equals to (6), which indicates the duty cycle at this point is only concerned with R o and R s . As shown in Fig. 7, it is kept constant with the variation of V s (the same to V o ). ...
Voltage stabilisation is indispensable for every energy converter, including a wireless power transfer system. With the increase of frequency, the resistance of the receiving coil would turn out to be elevated obviously, which would lead traditional voltage regulators composed by a buck–boost converter to existing an unsteady operation region. A logical control scheme is proposed to overcome this obstacle, which could self‐adaptively stabilise the output voltage without the course of feedback. The proposed method could realise the function of voltage stabilising at a larger range of distance comparing to the traditional scheme of buck–boost converter with the same conditions. Two improved structures are built based on the proposed scheme to prevent buck–boost converter stepping into the unsteady region, and experiments are finally implemented to verify the effectiveness and correctness of the proposed method.
This paper presents a novel closed-loop frequency control algorithm that captures the resonant frequency of a Wireless Power Transfer (WPT) system to obtain high-efficiency at maximum power transfer in moving electric vehicles. The control algorithm of the WPT system is designed regarding the WPT has magnetically coupled series-series resonant circuit topology. The study mainly focuses on catching the resonant frequency depending on the changes in air gap, load, and inductance. The proposed algorithm is able to detect the resonant frequencies, allowing the maximum power transfer under inductive, ohmic, or capacitive behaviour of the system. Simple, fast and cheap structure of the algorithm renders obtaining the resonant frequency in a wide frequency range. Moreover, once the resonant frequency of the inverter is obtained, switching loss is minimized by leveraging Zero Current Switching (ZCS). The numerical simulations of the control algorithm are performed in MATLAB/Simulink. Furthermore, a Finite Element Method (FEM) analysis is conducted by utilizing co-simulation of Ansys Maxwell 3D -Simplorer -MATLAB/Simulink. Finally, the developed system is experimentally tested for several air gap values and it is verified that the system is able to operate with high efficiency for the distances less than the critical air gap.
In this paper, we propose a method to optimize the output power, efficiency, and cost of the dynamic wireless charging (DWC) system of electric vehicles by using the transmitting coil spacing as the decision variable. In a set of transmitting equipment, we adopt a structure with two transmitting networks in parallel and derive loss models. The expressions of the output power and efficiency of the DWC system are obtained by data fitting. In addition, combined with the proposed cost function, we construct a multi-objective optimization problem on output power, efficiency, and cost. Due to the complexity of the objective function, it is difficult to solve the problem by the analytic method, and thus we propose a constrained adaptive particle swarm optimization (CAPSO) algorithm with high accuracy to solve the problem. Finally, the simulation results verify the feasibility of the proposed model. The advantages of the proposed CAPSO algorithm and the optimization results under different weight combinations are presented.
The interaction between the resonant wireless power transfer (WPT) component and the dc/dc converter may weaken the system stability, causing overshoot and oscillation in the dynamic process of such WPT system. Nevertheless, both the mechanism and the solutions of the above problems are not fully researched for the WPT systems. This paper first analyzes the small-signal impedance characteristics of such systems and points out the cause of the instability phenomenon. Then, a novel control strategy is proposed to regulate the system impedance characteristics, which can suppress the interaction and improve the system dynamic performance. Small-signal analysis and experiment results demonstrate that the proposed strategy has the advantages of fast response and less overshoot compared with traditional PI control, and is suitable for different operating conditions.
