Power Transfer Model Research Articles

Precise Modeling of Inductive Wireless Power Transfer With Lossy Magnetic Sheets

Precise Modeling of Inductive Wireless Power Transfer With Lossy Magnetic Sheets

Co-optimization energy management strategy for a novel dual-motor drive system of electric tractor considering efficiency and stability

The challenge in developing an electric tractor control strategy lies in operating efficiently and smoothly in most conditions. This paper put forward a co-optimization energy management strategy (EMS) for dual-motor electric tractors to achieve working efficiency and smoothness simultaneously in typical conditions including ploughing, rotary tillage and transportation. Firstly, the mathematical models for components of the drive system are established, such as the power transfer model and gear shifting model. Secondly, the novel EMS combining demand torque calculation method (DTCM) and driving torque distribution strategy (DTDS) is proposed, which is based on nonlinear PID control and modified snake optimizer (SO) algorithm respectively. Then, the hardware in the loop (HIL) platform is manufactured, and load data for the HIL test collecting by a tractor operating in the field. Finally, the performances of the electric tractor with the novel EMS in three typical conditions are validated. It shows that EMS can identify the demand torque accurately. Compared to the rule-based algorithm with reasonable parameters, the novel EMS improves efficiency and stability significantly, especially in ploughing increasing efficiency by 14.44% and decreasing jerk fluctuates by 73.33%. The research results can provide theoretical references for developing the EMS of the electric tractor.

A Unified Design Approach of Optimal Transient Single-Phase-Shift Modulation for Nonresonant Dual-Active-Bridge Converter With Complete Transient DC-Offset Elimination

The dynamics of nonresonant dual-active-bridge converter (DABC) are simultaneously affected by the transient modulation strategy and controller design. In general, inappropriate transient modulation strategies can lead to nonzero transient dc offsets in the inductor current and transformer’s magnetizing current, thus introducing excessive trajectory tracking error and time delays between the pulsewidth modulation generator and controller. Consequently, truly optimal transient responses cannot be achieved solely through a high-performance controller, unless the modulation-induced transient dc offsets can be completely eliminated. This article presents a comprehensive review of the optimized transient phase-shift modulation (OTPSM) strategies for single-phase-shift modulated DABC, and derives a novel optimal modulation method referred to as symmetric single-sided OTPSM (SS-OTPSM), which is based on a unified theoretical framework of OTPSM and an additional condition enabling a full elimination of all undesired transient dc offsets. The proposed SS-OTPSM can be easily and cost-effectively implemented in a cycle-by-cycle manner, and inherently compatible with fast controllers. Additionally, in order to more accurately match DABC’s power transfer model under SS-OTPSM, an enhanced model predictive controller (EMPC) is proposed. By a combined use of SS-OTPSM and EMPC, ultrafast and completely dc-offset-free dynamics can be achieved without measuring the inductor current. The effectiveness of the proposed schemes is verified by closed-loop simulation and experimental results.

Wireless power transfer system with dual‐frequency operation in transmitter side for motor control application

AbstractIn this paper, a transmitter‐side control method is proposed in inductive wireless power transfer (I‐WPT) model for the speed and power control of a single‐phase induction motor (SPIM). Resonant tanks with an electronic driving mechanism are used in the proposed configuration. The receiver side employs two resonant circuits with two full wave rectifiers, comparator, and two gate drivers for the management of the motor speed and power. The resonant circuits and electronic motor drive are presented through detailing the mathematical model and system design. In addition, a comparative section of the proposed model with the previous art is introduced to address the contributions of the paper. Moreover, a prototype model of the proposed topology has been created in simulation environment and tested in a variety of scenarios. The proposed I‐WPT model has a power rating of 140 W, whereas the SPIM has a power rating of 120 W. At full power operation, a 130 W power is supplied from the source during 118 W power consumption of SPIM, indicating that the system's efficiency is over 90%. The motor speed control has been tested by lowering the operation frequency of the motor terminal voltage from 60 to 40 Hz and from 40 to 20 Hz. The dynamic motor power has been also analyzed by reducing the load power from 100% to 70%. The findings reveal that the proposed transmitter‐side controlled I‐WPT system operates in a wide range of circumstances.

Safety Enhancement by Optimizing Frequency of Implantable Cardiac Pacemaker Wireless Charging System.

Wireless charging devices for implantable cardiac pacemakers have not been clinically applied. For actual applications, safety assessments of a wireless charging system must be conducted. For systems with a certain power, frequency is one of the important factors that directly affect safety. This paper aims to study the safety evaluation method and optimal operation frequency of a cardiac pacemaker wireless charging system. The wireless power transfer (WPT) model considering the coils' AC resistance is established, which is more in line with the actual situation. The analytical solution to the current in coupling coils is derived, which reveals the effect of the frequency. The currents used in electromagnetic and thermal simulations are calculated or measured for different charging prototypes. A safety evaluation method that comprehensively considers specific absorption rate (SAR), electric field, efficiency, temperature rise and electromagnetic interference (EMI) is proposed. In particular, the temperature rise is an innovative perspective as it has rarely been studied in previous literatures. The optimal frequency of a 3 W wireless charging system for cardiac pacemaker is determined based on the results of safety evaluation. The theoretical temperature rise reaches the minimum at 203 kHz, and the theoretical energy loss reaches the minimum at 260 kHz. The comfort and safe frequency band is approximately from 150 kHz to 370 kHz based on theoretical and experimental results, and the optimal frequency band from 200 kHz to 300 kHz is recommended.

Analysis and modeling of wireless power transfer supported by quadratic boost converter interfaced fuel cell power source

AbstractThis study presents a novel wireless power transfer (WPT) system structure that transmits electrical energy from a fuel cell (FC) stack integrated with a quadratic boost converter (QBC). The main objective of the proposed study is to provide a high voltage conversion QBC based WPT system to transfer power from a low voltage FC energy unit. To adjust the power flow from the FC unit with nonlinear production behavior, a pre‐regulating WPT system is developed with QBC located on the transmitting side. Besides, the design procedure of the system with analytical equations is expressed in detail. To validate the viability and effectiveness of the proposed WPT system, a 100 W proof‐of‐concept model is developed with Horizon H‐100, and analyzed for different case studies, including dynamic operating and loading conditions. The constructed WPT system is performed for 80%, 90%, and 100% loading situations. At full loading, the performance results show that the load‐side consumes power in the rating of 77.8 W while the FC power source generates approximately 93.1 W. In this case, the efficiency of the system corresponds to 83.6%. Besides, the efficiency of the complete system is analyzed under various operating conditions.

An efficient design of LC-compensated hybrid wireless power transfer system for electric vehicle charging applications

Wireless power transfer (WPT) is the technology of transferring the electric power through a time-varying electric or magnetic field acting as a transmission medium. A combination between the inductive power transfer (IPT) and the capacitive power transfer (CPT) has been recently developed to benefit from the merits of both systems in order to realize high power transfer with high efficiency through large air gaps and misalignment distances. The output power capability of the existing designs is still limited and needs further enhancement. In this paper, a new hybrid inductive and capacitive wireless power transfer model is proposed, analyzed and simulated. The inductive part composes of a circular spiral coil integrated with a helical coil and supported with cross shape ferrite bars in order to enhance the magnetic coupling ability. The capacitive part consists of four cylindrically evacuated square plates compatible with the inductive part size to facilitate the combination process. Firstly, the system structure is designed using Maxwell-3D simulation tool, then an equivalent circuit model is derived in detail to explicate the working principle. Secondly, a 10.1 kW hybrid system is designed and simulated using MATLAB/Simulink and ANSYS/Simplorer. Excluding the inverter and the rectifier internal losses and considering only the AC losses of the coils represented in their parasitic resistance, a high resultant efficiency equal to 99.37% at a resonant frequency of 1 MHz is achieved. Generally, the results show that the hybrid system could perform better under different air gaps and misalignments than the inductive and the capacitive systems separately.

Modified first harmonic approximation-based modeling of SN-compensated inductive power transfer links operating at load-independent-voltage-output frequency

Some popular applications of wireless power transfer (such as electric vehicle charging) include a transmitter residing on a static platform (charging station) and a dynamic receiver (vehicle). In such applications, compensation may be excluded from the receiver in order to minimize, simplify and lower the cost. If transmitter compensation is also maximally simplified series to none (SN) compensation topology is created. It was recently shown that classical first harmonic approximation (FHA) based analysis fails to accurately predict RMS values of system currents, thus overestimating the achievable coil-to-coil efficiency. Consequently, this paper establishes modified FHA (MFHA) equivalent circuit of SN-compensated inductive power transfer link (IPTL), utilizing analytical expressions of primary and secondary currents based on time-domain differential equations (DE) based solution. It is shown that the outcomes of proposed MFHA and DE methods are very close, justifying the proposed methodology. Simulations and experiments demonstrate excellent matching, validating the presented analysis.

Modeling Single-Wire Capacitive Power Transfer System With Strong Coupling to Ground

This article presents the modeling of a single-wire capacitive power transfer (CPT) system to reveal its power transfer mechanism with strong coupling to ground. An equivalent circuit is proposed by treating the ground as a quasi-conductive medium. The parameters of the equivalent circuit model are determined, including the capacitance between the coupling plates of the CPT system, the single-wire inductance and capacitance between the wire and the ground, and the ground equivalent impedance. The maximum power transfer capacity corresponding to the system's resonant frequency is analyzed by using the proposed model to guide the system tuning design. A prototype single-wire CPT system is built, and a computer simulation technology (CST) model is undertaken to show the electric and magnetic field distributions, and the Poynting vector indicating the direction and magnitude of the power flow in the system. It is shown that the output voltage and the power predicted by the theoretical model are in good agreement with the simulation and practical results under the frequency and load variations. Different lengths of the dangling single wire at the secondary side of the CPT system are also investigated to validate the model with different levels of ground effects.

Optimization of Multi-energy Transfer Considering Internal Interaction and External Collaboration in Micro-Energy Network Group

Micro-energy network realizes the complementary of distributed energy production according to the characteristics of users’ energy demand and local resource conditions. In order to realize the efficient operation of micro-energy network group, this paper proposed an optimal power transfer model based on Mutual Energy Supporting Pattern in micro-energy network group. The concept of micro-energy network is given and the basic structure of micro-energy network group based on the interconnection of external energy hubs is first established. Then, the micro-energy network model of internal energy hub and optimal power transfer model is established. The optimal power transfer model of micro-energy network group is subdivided into two kinds of operation modes, the internal cooperation mode and the synergy cooperation mode. The internal cooperation mode is to address the problem of energy shortage at the micro-energy network, while the synergy cooperation mode is to solve the problem through the coordination of multiple energy hubs in the micro-energy network group. Finally, the model is validated by a system including electricity, gas, heat/cooling load and external energy hub.

Energy Shaping Control for Wireless Power Transfer System in Automatic Guided Vehicles

This paper proposes an energy shaping controller of a DC/DC converter for automatic guided vehicles (AGVs) wireless power transfer (WPT). A transformer is inserted after the LCC topology to improve the transfer power, and the DC/DC boost converter is added before this topology to obtain desired systematic power dynamically. The system power transfer model is derived based on the idea of voltage transformation and the desired power can be implemented indirectly through regulating desired output voltage of DC/DC converter. With the proposed controller, this WPT system will have a much better dynamic performance and the effective working time can be increased significantly. Furthermore, this paper proposes dynamical regulation strategy for output power to get real time target power according to the charging curve of the battery. Simulation and experimental results verified the control performance of the proposed control scheme. A WPT prototype with power up to 1.65 kW was built, and 92.12% efficiency from DC power source to battery load is achieved, which is 4% higher than that obtained by the conventional PID method.

Analisa Desain, Konsep, dan Karakteristik Sistem Transfer Daya Nirkabel

<p>In the current era of the industrial revolution 4.0, the need for time, labor, and cost efficiency is a basic requirement for human life, especially regarding electrical energy sources. The supply of commercial electricity is still using electricity cables to deliver electricity to the load. Therefore, one of the ways of sending or transferring electrical power that continues to be developed today is wireless electricity transfer. The wireless transfer of electric power has several advantages compared to the use of cables, which can increase the convenience in the use of electrical equipment and can reduce the amount of electronic waste. This research will study the techniques or methods of near-field wireless energy transfer systems, namely the inductive coupling method, the magnetic resonance coupling method and the capacitive coupling method. The results of this study propose an optimal modeling of wireless power transfer so that results and quality are better, taking into account the distance between the sender and receiver because the work efficiency of wireless power transfer decreases with respect to distance. And the signal transmission frequency is low for inductive coupling, while the resulting frequency will be high on magnetic resonance coupling and capacitive coupling.</p>

Optimization & validation of Intelligent Energy Management System for pseudo dynamic predictive regulation of plug-in hybrid electric vehicle as donor clients

In developing countries, policies for discarding the existing Internal Combustion (IC) Engine vehicles for faster adoption of Electric Vehicles’ not only creates burden on the existing power grid but also is impractical. The conversion of Conventional IC Engine based Online Taxis or public transport vehicles into Plug-in Hybrid Electric Vehicles donor clients, to participate in Vehicle to Grid & Vehicle to Vehicle power transfer model, is the solution. These vehicles would not only have emissions within compliance standards but would also reduces the load on the power grid meanwhile making an income through power transfer. The Intelligent Energy Management System (IEMS) developed makes use of a Non Dominated Sorting Genetic Algorithm (NSGA-II) based Pseudo dynamic predictive regulation approach on the powertrain to optimize the emissions, fuel cost and traction battery SoC. If the vehicle intends to participate in power transfer, the IEMS would predetermine the amount of SoC that would be used for an upcoming journey using Global Positioning System(GPS) data interconnected with a server unit which enables the IEMS to optimize the operating conditions of the vehicle. The modelled IEMS performance is tested for a given driving cycle with varying traffic levels on a virtual simulation environment using the IPG CarMaker software. A prototype with a 150 cc, 7.5 kW IC engine integrated to a 3 kW BLDC traction motor is developed and the response to the predictive model is evaluated and found to provide 27.66%, 13.73% and 7.72% equivalent energy to micro grid for low, medium and high criticality conditions for the user.

Investigation and Modeling of Multi-Node Body Channel Wireless Power Transfer.

Insufficient power supply is a huge challenge for wireless body area network (WBAN). Body channel wireless power transfer (BC-WPT) is promising to realize multi-node high-efficiency power transmission for miniaturized WBAN nodes. However, the behavior of BC-WPT, especially in the multi-node scenario, is still lacking in research. In this paper, the inter-degeneration mechanism of a multi-node BC-WPT is investigated based on the intuitive analysis of the existing circuit model. Co-simulation in the Computer Simulation Technology (CST) and Cadence platform and experiments in a general indoor environment verify this mechanism. Three key factors, including the distance between the source and the harvester, frequency of the source, and area of the ground electrodes, are taken into consideration, resulting in 15 representative cases for simulation and experiments studies. Based on the simulation parameters, an empirical circuit model to accurately predict the received power of multiple harvesters is established, which fits well with the measurement results, and can further provide guidelines for designs and research on multi-node BC-WPT systems.

Analytical modeling of power transfer via metallic nanoparticles in a solar cell absorber

Metallic nanoparticles scatter sun light efficiently at resonance wavelength where the scattering and absorption in the nanoparticles are highly influenced by shape, size, material composition, host medium, and volume fraction of the nanoparticles in the host medium. We present transfer matrix method and Mie theory based a modified analytical model to optimize the scattering property of nanoparticles and to simulate power transfer from the metallic nanoparticles (Ag, Au, Cu, and Al) layer into an absorber layer (n-GaAs). We compare the performance of nanoparticles with bare n-GaAs layer. We found that Al-nanoparticles based structures show higher power transfer in the absorber layer than Ag, Au, and Cu nanoparticles.

Small-Signal Modeling and Analysis for a Wirelessly Distributed and Enabled Battery Energy Storage System of Electric Vehicles

This paper presents small-signal modeling, analysis, and control design for wireless distributed and enabled battery energy storage system (WEDES) for electric vehicles (EVs), which can realize the active state-of-charge (SOC) balancing between each WEDES battery module and maintain operation with a regulated bus voltage. The derived small-signal models of the WEDES system consist of several sub-models, such as the DC-DC boost converter model, wireless power transfer model, and the models of control compensators. The small-signal models are able to provide deep insight analysis of the steady-state and dynamics of the WEDES battery system and provide design guidelines or criteria of the WEDES controller. The derived small-signal models and controller design are evaluated and validated by both MATLAB®/SIMULINK simulation and hardware experimental prototype.

Analysis and Design of an Air-Coupled DC Transformer with a Hybrid Modulation Control Method

DC micro-grid is gaining increasing attention recently due to its highly efficient energy utilization and flexible energy exchange capabilities. In this paper, an air-coupled DC–DC transformer is proposed for the interconnection between the active load and the DC microgrid. The generic problems in an air-coupled power transfer system without ferromagnetic structure are discussed. A bidirectional half-bridge topology is also proposed to suit the characteristics of the stationary load and to realize the bidirectional power transfer between the active DC load and the DC grid. A Hybrid Modulation Method (HMM) is proposed; the small signal model is derived and linear control techniques are applied to the forward power transfer control, and phase model control is applied to the reverse power transfer model. The open-loop system is simulated by PSIM to get the characteristics of the forward and reverse transfer model, and the closed system is built in the MATLAB/SIMULINK to verify the effect of the forward frequency control method and the reverse phase control method. The prototype is built with a dsPIC controller, tests are performed to evaluate the characteristics of the transformer and the power flow control of the bidirectional power transfer.

Modeling and Experimental Verification of Bidirectional Wireless Power Transfer

This paper systematically elaborates the mechanism and experimental verification of bidirectional wireless power transfer (WPT) technology. The mathematic model of bidirectional power flow is presented and a phase-angle control method is introduced to effectively regulate the direction and magnitude of power flow in one WPT device. Simulation and experiments are carried out to verify the effectiveness of bidirectional WPT and its control algorithm. The measured results match well with the bidirectional power flow mechanism, and thus lay some bases for implementing large-scale bidirectional WPT device developments.

Modeling and Experimental Validation of a Butterfly-Shaped Wireless Power Transfer in Biomedical Implants

Wireless power transfer (WPT) presents a safe and robust method for powering biomedical implants. The range and misalignment tolerance restrictions of the WPT system are the main factors, conducive to the transfer efficiency degradation. Especially, the implanted device is invisible and difficult to arrange in alignment with the transmitting coil. This paper proposes a butterfly-shaped transmitting (BS-Tx) coil of a magnetic resonance WPT system for biomedical implants. The BS-Tx coil prototypes with the changing driven current directions, parallel and anti-parallel current directions, are verified and analyzed. Besides, an equivalent circuit model of a coupling two-coil system with an optimal pair of capacitors method for the matching network is mathematically derived to obtain the maximized power transfer efficiency. The BS-Tx coil enhances the efficiency of the system in the distance, angle, and axial misalignment tolerances. A practical WPT system is fabricated and measured to verify the transfer efficiency through the real biological tissue and exhibits a significant efficiency improvement. Finally, a hypothetical context of retinal prosthesis application is demonstrated as a potential application to retinal implants. The proposed system shows a low specific absorption rate, that is satisfied the human safety regulations.

Bidirectional microphone array with adaptation controlled by voice activity detector based on multiple beamformers

Ambient noise suppression in a reverberant room is usually performed by the microphone array. The adaptive beamforming, whose typical representative is minimum variance distortionless (MVDR) beamformer, is an effective method for noise suppression. However, MVDR beamformer gives poor results in the real room because of its sensitivity to the steering error and the multipath wave propagation. In this paper we propose a noise suppression method based on assumption that the positions of the speakers in the reverberant room are roughly known. Noise reduction is realized by two MVDR beamformers directed toward each of the speakers. Adaptation of the MVDR beamformers are controlled by a speaker activity detector which decision is based on power transfer model of the multiple superdirective beamformers in combined diffuse and coherent noise field. The proposed voice activity detector also provides residual noise reduction. The proposed method and its robustness to steering error were tested on the model of simulated room as well as in real room environment. The improvement of the restored speech signal was evaluated by Signal to Noise Ratio Enhancement (SNRE) and by Perceptual evaluation of speech quality (PESQ) measure.