Efficiency Optimization of Wireless Power Transfer System for Electric Vehicle Based on Improved Marine Predators Algorithm

<sec>Magnetic resonance wireless power transfer (WPT) has gradually become a popular research topic of near-field regulation in recent years, with wide applications in the fields of mobile phones, implantable medical devices, electric vehicles, and many other fields. However, several challenges remain to be addressed: near-field coupling, which induces multiple frequency splits and prevents the system from maintaining a fixed operating frequency; coupled arrays, which are susceptible to structural errors and parameter perturbations; current research, which primarily focuses on single-load transmission and has resulted in undeveloped multi-load transmission systems; the direction of transmission, which is difficult to control flexibly. In recent years, photonic artificial microstructures have provided a flexible platform for studying topological physics, arousing significant research interest in their fundamental topological characteristics. The most prominent features of topological structures are their nonzero topological invariant and the robust edge states determined by the bulk-edge correspondence: these features can overcome disturbances caused by defects and disorders. Moreover, by modulating the wave function distribution of topological states, energy can be precisely localized, enabling directional WPT. Therefore, implementing topological modes in WPT systems are of significant scientific importance.</sec><sec>This review summarizes recent researches on topological models for robust WPT, which are divided into three main parts. The first part introduces one-dimensional periodic topological structures, focusing primarily on the significant improvements in transmission efficiency and robustness achieved by utilizing topological edge states in the Su-Schrieffer-Heeger (SSH) model for WPT. Moreover, a composite chain formed by two SSH chains is constructed to realize a higher-order parity-time (PT) symmetric topological model. This approach solves the frequency splitting caused by coupled edge states and exhibits lower power losses in standby mode. The second part discusses several types of aperiodic one-dimensional topological chains. By introducing topological defect states at the interface between two different dimer chains, robust multi-load WPT is achieved. Furthermore, based on the integration of artificial intelligence algorithms, the SSH-like topological model enables more efficient and robust WPT than traditional SSH model. The asymmetric edge states in quasi-periodic Harper chain provide a solution for directional transmission in WPT applications. By introducing nonlinear circuits, this model enables active control of the transfer direction. The third part presents the application of high-order topological corner states in multi-load robust WPT, demonstrating the selective excitation of both symmetric and asymmetric corner modes.</sec><sec>Finally, the application prospects of topological modes in WPT systems are discussed. With the development of new physics, the integration of non-Hermitian physics and topological physics holds great promise for achieving simultaneous energy-information transfer, and is expected to achieve compatible WPT, wireless communication, and wireless sensing within a single system. Such a fusion technology will provide breakthroughs in efficiency, robustness, and multifunctionality for next-generation wireless systems.</sec>

In multi‐input and multi‐output (MIMO) wireless power transfer (WPT) systems, the destructive interference between multiple transmitters and receivers brings a serious impact on power transmission efficiency. This paper proposes a voltage control strategy to maximize the transmission efficiency of a MIMO WPT system by controlling the amplitude and phase of the transmitter voltages. However, the complexity of the realistic WPT circuit topology and the uncertainty in the related parameters obstruct the establishment of an accurate closed‐form description of the WPT model to optimize the transmission efficiency of the system. In this paper, a simple multi‐port network model is introduced to simulate a MIMO system to avoid the complex circuit topology and a large number of circuit elements. To determine the parameters of the proposed model, a simple yet efficient methodology, by sequentially changing the excitations of the input ports and sampling the responses at the out ports, is proposed. A voltage control methodology to optimize the transmission efficiency of a MIMO wireless power transfer system is finally developed. To validate the proposed model and voltage control methodology, a three‐input and three‐output WPT prototype is designed and fabricated and used as the experimental platform. The performances of the proposed voltage control methodology are compared to both the experimental ones and those without the proposed voltage control methodology.

This paper presents a two-coil reconfigurable wireless power transfer (WPT) system topology in order to optimize transmission efficiency under different transmission distance (DIS) and lateral misalignment (MIS) conditions. The reconfigurable WPT system includes one transmitter (Tx) side and one receiver (Rx) side but it could switch between different circuit configurations (which are made up of different values of series and shunt capacitors) at Tx side and/or Rx side. Design guidelines of the two-coil reconfigurable WPT system are devised based on an equivalent circuit model. A proof of concept prototype with three different adaptive configurations at Tx side and one configuration at Rx side is built and experimentally compared with conventional two-coil WPT system. Results show that when the system is perfectly aligned, the reconfigurable system improves the transmission efficiency by up to 20%. When system is laterally misaligned, the transmission efficiency is improved by up to 19%.

The magnetic fields (MF) generated in close proximity to high power wireless power transfer (WPT) systems generally exceed exposure limits and might also violate basic restrictions (BR). However, there are as yet no available standards describing methods to measure the MF generated by WPT systems. In this study, a new method for demonstration of compliance with the BR in the close proximity to sources at frequencies from 3 kHz to 10 MHz is proposed. This approach mitigates overestimation by incident field assessment in strong field gradients close to WPT systems. The spatial peak MF amplitude and gradient generated by WPT systems are measured with a field gradient probe at the closest location to the source. The induced fields and absorbed power are then calculated on the basis of specific transformation functions for testing of compliance with the BR of all international safety guidelines.

The article consists of three parts. The analysis of existing technologies of wireless power transfer (WPT) is carried out in the first part. It is noted that one of the factors that determines the choice of one or another WPT technology is the distance over which the power is transmitted and the type of electromagnetic (EM) energy used. The essence of WPT technologies in the near zone, Fresnel zone and Fraunhofer zone is explained. A generalized block diagram of the WPT system is presented. Areas of application and trends in the further development of the WPT technologies over short distances using induction and resonance methods, the WPT technologies over long distances, the technology of EM energy harvesting from the surrounding space and its conversion into direct current for powering low-power devices are considered. The achievements of the team of the antenna laboratory of the Kharkiv National University of Radio Electronics (KhNURE) in the area of WPT are presented in the second part of the article. Namely, the electrodynamics’ approach is considered which is based on a single idea about the functioning of WPT systems and which include antennas and their circuits and ways of excitation with nonlinear elements. The stages of building a nonlinear mathematical model (MM) of the electrodynamics’ level of the WPT system are presented, according to which the entire WPT system, which generally includes the transmitting subsystem and the receiving subsystem, is considered as a single multi-input antenna system with nonlinear characteristics. The proposed MM provides a complete representation of the WPT systems operation of a wide class and purpose, in which fundamentally different WPT technologies are used. The third part of the article presents new results related to continued research. The analysis of the adequacy of the developed MM of WPT system is carried out. The results of simulation of WPT systems with the induction method of energy transfer (near zone) and their comparison with theoretical and experimental data of other authors showed the reliability and universality of the proposed approach and the MM of WPT system developed on its basis.

The wireless power transfer (WPT) system based on parity-time (PT) symmetry has the advantages of robustness, stable, and efficient power transmission. However, the region of PT symmetry is limited, which cannot satisfy some practical requirements. Multiple transmitting coils have been shown to improve the misalignment tolerance of WPT systems. Towards this end, a parity-time-symmetric-based WPT (PT-based WPT) system with double-transmitting coil is presented in this article. First, an approximate equivalent circuit model of this PT-based WPT system was developed. Second, compared with the conventional single transmitting coil PT-based WPT system, the proposed system expands the PT symmetry region and provides higher output power and transmission efficiency. Furthermore, the mutual inductance between two transmitting coils can be designed to meet the requirements of different scenarios, which improves the freedom of system design. Finally, a 30 W prototype is designed to evaluate the proposed WPT system. Experimental results show that the critical coupling coefficient is reduced by about 12.5% at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> = 0.51, which implies a longer transmission distance. Moreover, the maximum output voltage fluctuation in the strongly coupled region is only 3.5%, while the transfer efficiency is approximately constant, which implies stable and efficient power transfer.

A Wireless Power Transfer (WPT) system, known for its contactless power delivery, is extensively used for power supply in spacecraft applications. Achieving efficient and stable power transfer necessitates the integration of DC/DC converters on both the primary and secondary sides of WPT systems for power conversion and control. Traditional efficiency optimization methods primarily focus on impedance matching within the wireless power resonance network, often neglecting the overall efficiency optimization of multi-stage DC-DC and WPT systems. This oversight results in suboptimal overall system efficiency despite optimal efficiency in the wireless transmission segment. Additionally, the time-varying nature of mutual inductance and load parameters during power transmission in WPT systems presents challenges for maximum efficiency tracking and power control. This paper introduces a multi-level coordinated control efficiency optimization method for WPT systems utilizing the particle swarm optimization (PSO) algorithm. This method takes into account the transmission losses across all power conversion units within the WPT system, establishing a mathematical model for the joint optimization of overall system transmission efficiency and power. The PSO algorithm is then employed to solve this optimization model using estimated mutual inductance and load values. By adjusting the DC/DC converters on both sides, the method ensures optimal overall system efficiency and consistent power transmission. Experimental results indicate that under varying load and mutual inductance conditions, a Series–Series (SS) compensated WPT system using this method achieves a 200 W power output with maximum efficiency tracking, a power output error of 0.63%, and an average transmission efficiency of 86.2%. This demonstrates superior power transmission stability and higher efficiency compared to traditional impedance matching methods.

A wireless power transfer (WPT) system via magnetic resonance coupling method is attracting attention to high convenience. A WPT system has problems such as power transmitting loss and output voltage fluctuation due to the change in the coupling coefficient and the load state. In previous method, sliding mode control system as a tracking controller considering nonlinearity and uncertainty has been proposed, but the output of this control system had bias and chattering. This paper proposes operator-based nonlinear sliding mode control system to reduce chattering and bias simultaneously for a WPT system using buck converter. First, the model of the WPT system using rectifier and buck converter is explained and dynamics formulas are derived. Next, the proposed operator-based nonlinear sliding mode control system design for the WPT system is described and tracking performance is confirmed. Finally, the result of simulation of constant voltage control and comparison with the previous method is shown.

Exploring Dielectric Resonator Antennas (DRAs) in Electric Vehicles (EVs) Wireless Power Transfer (WPT) systems is the focus of this study. DRA technology has gained prominence for its unique advantages, offering high efficiency and compact form factors in comparison to conventional antennas. In the context of EVs, the integration of DRAs in WPT systems has shown promising results in addressing challenges related to charging efficiency and spatial constraints. The resonant properties of DRAs enhance power transfer efficiency by mitigating impedance mismatches and reducing energy losses during transmission. Furthermore, the dielectric material properties of DRAs contribute to minimizing electromagnetic interference and enhancing the reliability of WPT in EV applications. This highlights the potential benefits of employing DRAs in achieving robust and efficient wireless charging solutions for electric vehicles. The study encompasses theoretical analysis, simulation studies, and practical implementations to validate the performance of DRAs in WPT systems. The findings suggest that DRA-based WPT systems present a compelling avenue for advancing the state-of-the-art in EV charging technology with efficiency of 84%, providing a more streamlined and effective approach to meet the growing demands of electric mobility in scooters.

Many researches have been carried out by previous researchers to get better performance of a wireless power transfer (WPT) system. This research uses a partitioned shielding made of metallic material to protect WPT system from electromagnetic interference (EMI). Also, a shielding material is connected to ground, so that it can reduce occurrence of stray/parasitic capacitance between electrodes of electronic components. Both the electromagnetic interference and the stray/parasitic capacitance can deteriorate performance of WPT system. In this research, the WPT system works at voltage 14.7V, frequency 56,298 Hz, distance coil to coil is 0 till 5 cm. The efficiency of WPT system is achieved until 14.9 % (without shielding) and until 17.9% (with partitioned shielding).

Wireless power transfer (WPT) is a promising technology for many applications such as electric vehicles, home appliances and various chargers. In some cases, there is also necessity of sending data along with power. In this paper, a new method for achieving this goal has been presented which combines the time division multiplexing (TDM) and frequency division multiplexing (FDM) in order to enable wireless power transfer link to send data via a same inductive link simultaneously. The proposed method ensures the full-duplex communication between primary and the secondary side of the wireless power transfer system. The uplink and downlink data carrier frequency have been set to 6.78 MHz and 13.56 MHz in ISM band respectively, although they could be set equally. In addition, the power carrier has been tuned at 22.4 KHz. The circuit analysis of the mentioned system has been provided and simulation results have been presented to show the effectiveness of the introduced scheme.

Current wireless power transfer (WPT) technology is widely used for various applications because of convenience and safety. One of the typical application of the WPT system is the near-field communication (NFC) system utilized mobile WPT system. However, WPT systems have problems with electromagnetic field (EMF) leakage which can cause electromagnetic interference (EMI) issues on the nearby electrical devices. In this paper, we propose the dual resonance NFC coil for EMF reduction. Proposed dual resonance coil generates resonance not only at the NFC operating frequency of 13.56 MHz but also at the wireless charging frequency 130 kHz. When comparing the proposed NFC coil with a typical NFC antenna, the total EMF level of the WPT system is reduced by 3.96 dB at 130 kHz without any effect at the NFC operating frequency of 13.56 MHz.

Wireless power transfer (WPT) systems’ efficiency is significantly impacted by non-monotonic variations in the coupling coefficient. For very short distances or strong-coupling cases, the WPT efficiency is minimal at the natural resonant frequency, with two peaks around this frequency, known as the frequency splitting phenomenon. On the other hand, WPT capability decreases for long distances or weak coupling cases. Therefore, adaptive matching is required for WPT systems with varying distances, like wireless charging systems for electric vehicles (EVs). This paper first presents a detailed analysis of the frequency splitting phenomenon by studying the root locations of the WPT system’s transfer function. Then, a real-time fixed-frequency adaptive impedance matching (IM) method is proposed, in which the amplitude and phase of the input impedance is estimated using the average active power, the average reactive power, and the amplitude of input voltage. Unlike traditional search-and-find techniques, the proposed method calculates the optimal IM network parameters only in a single iteration, which improves the convergent speed. A scaled-down 20-Watt prototype controlled by the TMSF2812 is fabricated and used to validate the effectiveness of the proposed method over a wide range of coil-to-coil distances.

In previous researches, an operator-based sliding mode control design to achieve high power transfer efficiency of a wireless power transfer (WPT) system via magnetic resonance coupling were shown. However, it is difficult to reduce the steady-state error by using SMC-based tracking controller. In this paper, an operator-based integral sliding mode control method is adopted to reduce the steady-state error in the WPT system. Moreover, high power efficiency should be achieved in the WPT system by using an impedance matching control. The effectiveness of the proposed method is verified by simulation results.

The expanding Electric vehicle (EV) market is fueled by the need for more efficient and dependable ways to recharge the battery. By eliminating the necessity for direct physical interaction between vehicles and charge equipment, the Wireless Power Transfer (WPT) methodology eliminates the drawbacks and risks associated with the conventional conductive system. The innovative WPT technique replaces the conductive charging system to keep a similar power rating and efficiency. Numerous strategies have been created to improve the effectiveness and dependability of the WPT model. As a result, this review article thoroughly analyses current major research articles that describe WPT technologies for EV charging. The papers are classified based on various coupling types along with magnetic couplers and shielding, compensation, misalignment tolerance and control methods in WPT systems. In addition, the possible research gaps and the challenges associated with the existing works of WPT systems are discussed. The reviewed results are analyzed based on performance metrics and implementation tools attained using above classifications and EMF exposure references employed in the WPT system. The comparative effectiveness is presented in the tables, diagrams, as well as interconnections for ease of presentation and conceptual understanding. The core asset of this article lies in the fact that the findings offer a good "one-stop" resource including both aspects of the system and with regard to the power stage. This review article also emphasizes the potential and obstacles of inductive wireless EV battery chargers. A developer can find this study will contribute substantially to selecting an optimum design for the enhancement of the WPT system.