Resonant Power Research Articles

Analytical Framework of S-Parameter-Based Efficiency for Secondary-Parallel Compensation WPT System to Authenticate Data Using VNA

Resonant wireless power transfer (R-WPT) is the most efficient system in near-field applications. Predominantly, four distinct resonant topologies exist for R-WPT to enhance the power transfer efficiency (PTE) under different load conditions. Here, the PTE is considered crucial for gauging the R-WPT system performance. In a typical experimental scenario, measurement of the PTE is performed by exciting the transmitter (Tx) coil with a sinusoidal signal using a high-frequency inverter source. Therefore, the input and output power measurements are conducted using an oscilloscope. Here, the measurement using an oscilloscope is highly susceptible to external noise. As an alternative, the vector network analyzer (VNA) is the most accurate instrument to measure <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula> -parameters with high precision, even at very high frequencies. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula> -parameter-based analytical expressions for evaluating PTE are available only for series–series compensation topology. Therefore, VNA usage is severely limited for experimental validation of the other compensation topologies. This article proposes an analytical evaluation of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula> -parameter-based PTE for secondary-parallel compensation topology as a contribution. Moreover, the mathematical proof is deduced to determine the active operating load condition for the secondary-parallel capacitor. Error analysis of experimental data is performed where the signal-to-noise ratio (SNR) of the measurement system is greater than 35 dB and the percentage error rate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> is less than 1.3%, which implies high precision and accuracy of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula> -parameter-based VNA measurement system.

Мостовой резонансный источник питания электродугового двигателя малого космического аппарата

In this paper, the applied problems of designing a bridge resonant converter with a high-voltage arc ignition system in the channel of an electric arc motor is solved. The development of a bridge resonant power supply is presented, a review and analysis of power sources of arcjet thruster of various capacities is carried out. The theoretical aspects of calculating the main parameters of the source are considered. The transfer function describing the gain of the resonant circuit of the power supply is given. With the help of the transfer function, gain diagrams are constructed for various values of the Q-factor of the contour. A prototype of a power supply, a starting system and an arcjet thruster is presented. A series of experiments aimed at identifying the operability of the source is carried out. According to the experimental results, the maximum output power of the source wiz 182,4 watts, and the maximum efficiency is 87,5 %. Frequency spectra of the output current of the power supply are obtained. The current-voltage characteristics for the Ar and N2 are constructed. In the course of the study, phenomena related to the chaotic dynamics of the arc in the engine channel are discovered. Chaotic fluctuations are observed at the moment of starting the engine and disappeared after steady-state operation.

Frequency multiplication in a high-current relativistic gyrotron for obtaining high-power THz-band radiation

Using averaged equations and 3D particle-in-cell simulations, we investigate the frequency multiplication regime in a high-current relativistic gyrotron operating in 0.1 THz frequency band. We demonstrate that the ratio of the 3rd harmonic power and the fundamental cyclotron resonance power can reach 0.4–0.8%, which aloows for obtaining the 0.3 THz radiation with sub-MW output power level.

An Intrabody Power Transfer System With Continuous Maximum Resonant Power Tracking

In this letter, we present an intra-body-power-transfer (IBPT) system that delivers power greater than 100 μW even across a 150-cm on-body distance. The proposed IBPT TX employs an FLL-based maximum-resonant-power-tracking (MRPT), which runs in the background to maximize the power delivered to the load (PDL). The proposed technique does not require any RX-to-TX back telemetry or searching phase, thus enabling uninterrupted power delivery. The PDL and power transfer efficiency are further improved by inducing parallel resonance at RX. Fabricated in a 180-nm BCD process, the proposed IBPT system achieves 136-μW PDL at 1.8-V DC output with 8.83% end-to-end power efficiency.

Resonant power transmission through a ridged circular aperture with variable aperture dimensions and its arrays

Resonant power transmission through a ridged circular aperture with variable aperture dimensions and its arrays

Deterministic N-photon state generation using lithium niobate on insulator device

The large-photon-number quantum state is a fundamental but nonresolved request for practical quantum information applications. We propose an N-photon state generation scheme that is feasible and scalable, using lithium niobate on insulator circuits. Such a scheme is based on the integration of a common building block called photon-number doubling unit (PDU) for deterministic single-photon parametric downconversion and upconversion. The PDU relies on a 107-optical-quality-factor resonator and mW-level on-chip power, which is within the current fabrication and experimental limits. N-photon state generation schemes, with cluster and Greenberger–Horne–Zeilinger state as examples, are shown for different quantum tasks.

Frequency offset suppression method for wireless power transfer based on nonlinear resonant network

SummaryIn magnetically resonant wireless power transfer (MR‐WPT) systems, transmitter, and receiver usually operate at the same resonant frequency. However, parameters of inductor, capacitor, or other components are susceptible to changes due to environmental factors and cause resonant frequency deviation. This would lead to decrease of transmission performance. To solve the problem, a wireless power transfer system based on a nonlinear compensation network is proposed to suppress frequency offset. The modeling of the nonlinear MR‐WPT system is first established. On this basis, the mathematical equation of the equivalent nonlinear circuit is deduced and the amplitude‐frequency response characteristics are analyzed. The influence of inductance parameter on the nonlinear characteristic is studied. Furthermore, the effects of excitation amplitude, compensation capacitance, load, and magnetic ring turns on the operating characteristics of the nonlinear resonant circuit are analyzed. The proposed nonlinear resonant wireless power transfer system is constructed and is experimentally studied. Compared with the traditional linear MR‐WPT system, the results show that frequency offset can be effectively suppressed, which ensures efficient transmission performance with the proposed method.

Series RLC Resonant Circuit Used as Frequency Multiplier

Currently, the design of resonant power converters has only been developed while operating in the steady state, while the design operating in the transient stage has not been considered nor reported. This paper is interested in testing the performance of the resonant circuits operating in the transient stage and finding applications where benefits can be obtained from this form of operation. One application in which it is possible to obtain benefits from designing resonant circuits in the transient state is in the area of frequency multiplication. Usually, to achieve frequency multiplication, it is necessary to resort to complex methods and special devices that increase the complexity of the design and the total cost of the circuit. This paper evaluates the performance of a series RLC resonant circuit operating in the transient stage and with an underdamped response acting as a frequency multiplier, where the oscillation frequency of the current in the resonant tank is “n” number of times the switching frequency of the square voltage source at the input with a duty cycle of D = 50%. To validate the analysis, a circuit was designed to deliver an output power of 30 watts to a resistive load, where the switching frequency of the square voltage source at the input was 500 kHz. Since a multiplier value “n” equal to fifteen was chosen, the current in the resonant tank reached an oscillation frequency of 7.5 MHz. The design methodology was validated by simulations in SPICE, complying with the established design parameters.

Cylindrical Magnetically Coupled Resonant Wireless Power Transfer System Based on Flexible PCB Coils

In this letter, we design a magnetically coupled resonant wireless power transfer (MCR-WPT) system on the conformal cylindrical surface based on the flexible printed circuit (FPC) coils. The coil has the advantages of small size, lightweight, and high bendability. We combine mathematics and simulations to explore the relationship between the self-inductance/mutual inductance of the flexible coil and the bending radius of the conformal cylindrical surface. Both theoretical and simulation results show that as the bending radius decreases linearly, the self-inductance and mutual inductance of the coil also decrease nonlinearly. In addition, as the bending radius decreases, the transmission efficiency (TE) decreases, and the resonant frequency shifts to a higher range. Finally, measured and simulated results agree well, which further validates the conclusions.

A novel low frequency current ripple suppression method for energy storage system in DC microgrid

• A novel control method is proposed for NF, QPR and LPF based on dual-loop control. • This method improves the suppression effect of secondary harmonic current (SHC). • This method also improves anti-load mutation ability. • SHC suppression effect and dynamic response of four control methods are analyzed. The instantaneous output power of the energy storage system pulsates at twice the output voltage frequency, generating a large amount of secondary harmonic current (SHC) in the switching tubes and batteries. The SHC is harmful to the system performance and battery life. Firstly, through the analysis of traditional dual-loop (DL) control method, it is concluded that SHC is not suppressed obviously and the dynamic characteristics of the system is inferior when load hopping. To address these two questions, a novel control method is proposed for introducing notch filter (NF), quasi-proportional resonator (QPR) and load power feedforward (LPF) based on DL control (it can be abbreviated as NQLDL). This method increases the amplitude of the inductor branch equivalent impedance (IBEI) at twice the output frequency without changing the frequency adaptability, improves the suppression effect of SHC, reduces the amplitude of the IBEI outside of twice the output frequency and also improves anti-load mutation ability. Furthermore, the SHC suppression effect and dynamic response are also discussed under four control methods. Finally, the validity of proposed control methods are demonstrated by experimental results.

A Tilted-Orthogonal Receiver Coil Antenna to Improve Misalignment Tolerance in WPT Systems

This article proposes a novel receiver (Rx) coil antenna to mitigate the lateral misalignment problem in resonant wireless power transfer (R-WPT) systems. The proposed design comprising two Rx coils is analytically optimized by parametric sweeping the tilt angle <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(\theta)$ </tex-math></inline-formula> . Consequently, the resultant structure is designated as a tilted-orthogonal Rx coil antenna with stable mutual inductance in the Rx active region. Therefore, regardless of the Rx misalignment, power transfer efficiency (PTE), realized using the circuit parameters, maintains its consistency. The analytical results of the proposed Rx coil antenna are experimentally verified. The misalignment tolerance of the proposed tilted-orthogonal Rx coil antenna is improved by 120.18% in terms of PTE compared with the conventional planar Rx coil antenna.

Optimization of MHz Wireless Power Transmission Distance Based on GaN Device

Aiming at the problems of low natural frequency and small transmission distance of traditional magnetically coupled resonant wireless power transfer systems, the GaN device is used as an inverter bridge to widen the natural frequency domain of the system, and the influence of the natural frequency and working frequency of the system on the transmission distance is studied in the high-frequency range. The natural frequency of the system is taken as a variable parameter from the perspective of the equivalent circuit, and together with the working frequency and transmission distance, it is used as the influencing factor affecting the output power of the wireless power transmission system. The expression of the system-normalized transmission power is obtained, and the relationship between the transmission distance and other parameters is analyzed. Finally, a complete set of a series-series wireless power transfer system based on GaN devices is designed. The results are promising and in agreement with theoretical analysis, verifying that under the system detuning coefficient of 0, the transmission distance corresponding to the maximum transmission power of the system will increase with the increase in the natural frequency of the system.

Electrical Schemes of Resonant Conversion of Reactive Power to Active

Problem. Today, it is extremely important to solve the problems of efficient conversion of various types of energy (solar, wind, thermal, etc.) into electricity, which is a non-alternative factor in the comfort of the existence and development of all mankind. In this regard, the undoubted interest in practically accessible technical developments aimed at solving the above problems of the modern electric power industry should be highlighted. So, for example, the transformation of reactive power into active power, which can be used to perform work for various purposes, is of interest. Goal. The purpose of this work is to propose and theoretically substantiate the effectiveness of possible schemes for a resonant reactive power to active power converter, combined by the presence of two inductively coupled active-reactive circuits and different ways of creating resonant conditions in each of them. Methodology. The calculated ratios for the theoretical substantiation of the effectiveness of the considered converter circuits are based on physically clear phenomenological provisions and a rigorous mathematical approach using the apparatus of the theory of electrical circuits. Results. For a circuit where resonance excitation is carried out by an appropriate choice of its parameters, the conditions are determined, the fulfillment of which minimizes the influence of the proposed circuit on the processes in the reactive power source at the maximum current in the converter load. The real parameters of the circuit are calculated, where, with the proper choice of its parameters, it is possible to carry out a real conversion of the input power (conversion coefficient ~ 1.0) with a minimal effect on the current in the reactive power source (decrease to ~ 8,5%). For a circuit with an additional source of harmonic voltage, it is shown that with an appropriate setting of a third-party source, it is possible to completely eliminate the negative effect of electromagnetic processes in the converter circuit on the output voltage and current of the reactive power source. Originality. The scientific novelty of this work lies in the proposal and analysis of possible schemes of the resonant converter of reactive power into active power, combined by the presence of two inductively coupled active-reactive circuits and different ways of creating resonant conditions in each of them. Practical value. The theory and numerical assessments of the characteristics of the processes occurring in the proposed circuits of the resonant reactive power converter are important for further experimental studies, as well as for formulating recommendations for the manufacture of various options for operating devices for the appropriate purpose.

A comprehensive review of control techniques for compensating the fault current in resonant grounded distribution networks: From the perspective of mitigating powerline bushfires

Powerline faults are responsible for major bushfires around the world where arcs provoked from ground faults are common causes for igniting such fires. The grounding techniques (mainly resonant grounding) used in distribution substations and arc suppression devices play a crucial role for compensating fault currents in order to extinguish arcs so that the likelihoods of powerline bushfires are significantly reduced. Though passive arc suppression devices (e.g. Petersen coils) are extensively used for compensating the reactive component of the fault current, the active component of this current is still large enough to ignite the fire in bushfire prone areas for which active arc suppression devices are recently used. These active arc suppression devices incorporate residual current compensation inverters and the full compensation of the fault current rely on the control scheme of these inverters. This paper comprehensively reviews different control schemes that are used for compensating the fault current in resonant grounded power distribution systems. The existing control schemes are discussed in terms of the model used during the controller design process, loop structures, control block diagrams, and performance analysis frameworks (i.e. the type of fault impedances). It is worth mentioning that faults on resonant grounded power distribution networks exhibit the characteristics of high impedance faults and it important to consider this aspect for performance analysis of the control scheme. This paper also covers a brief overview of different grounding techniques used for mitigating fault currents and finally, the challenges with the existing controllers are identified in terms of extinguishing powerline bushfires. The comprehensive review motivates and guides future research activities on developing more efficient fault compensation techniques.

Research on correlation model between transducer temperature and acoustic performance parameters of ultrasonic machining system

In the process of ultrasonic vibration cutting (UVC), the acoustic performance parameters of ultrasonic machining system change because of systems heating up and cutting loads. The changes of acoustic performance parameters will affect resonant frequency, impedance, and power match of the ultrasonic machining system, and stability of the amplitude of UVC system. It is hard to monitor the acoustic performance parameters online. Based on the analysis of the correlation mechanism between transducer temperature and acoustic performance parameters, the correlation models between transducer temperature and resonance frequency, static capacitance, and dynamic resistance of ultrasonic vibration machining system are established by curve regression analysis modeling method. The acoustic performance parameters of an ultrasonic vibration machining system are determined by transducer temperature using the correlation models. The effectiveness of the model is verified by experiments. It gives the information for the stability evaluation of the ultrasonic vibration machining process, the dynamic impedance matching of the ultrasonic machining system, and the power matching adjustment of the ultrasonic power supply.

Design of Electric Vehicle Battery Charger With Reduced Switching Frequency Variation

This article presents the design of an electric vehicle (EV) battery charger isolation stage for minimizing switching frequency variation with the proposed duplex control. Traditionally, the realization of an EV charger with a resonant power conversion stage involves extreme frequency variation in the constant voltage (CV) mode resulting in switching losses, imposes severe constraints on the optimal design of magnetics, and presents control complexities due to secondary resonance and degraded pulsewidth modulation resolution. In this context, reported hybrid control strategies are complex and entail the simultaneous variation of control variables. In order to simplify control complexity and design constraints, the EV charger isolation stage with the quadruple rectifier and employing the proposed duplex control is presented with notable frequency reduction. Furthermore, the effect of high-frequency transformer nonidealities on the soft-switching range is delineated. The proposed duplex control contributes to the efficiency enhancement of the EV charger over a comprehensive range during CV charging, ensures soft switching, and prevents secondary resonance. It also offers continuous resonant current to overcome the underutilization of the transformer arising from high-frequency distortions. To validate the presented analysis, a 1.25-kW hardware prototype is designed and tested in the laboratory, and experimental results are presented.

Development of a Resonant Auxiliary Power Supply Control Algorithm and Resonant Destruction Detecting for Railway Vehicles

In this paper, the method and a control algorithm for detecting resonant destruction of a resonant auxiliary power supply for railway vehicle are proposed. It is essential to reduce the weight of the electric equipment attached to the lower part of the railway vehicle because it greatly affects the life of the railway vehicle, such as wheel and bearing. In order to reduce the weight and volume of the auxiliary power supply, in the case of windings, high-speed switching should be performed by lowering the input voltage. Therefore, in this paper, the auxiliary power supply control algorithm using an LLC resonant converter to reduce the weight of auxiliary power supply for railway vehicle is proposed, and the method of detecting resonant destruction due to device failure of a resonant converter is proposed. The proposed algorithm steps down the wire voltage using an input buck converter for high-speed switching, and the inverter input voltage is controlled through the LLC resonant converter. In addition, ZVS (Zero Voltage Switching) is operated to minimize the loss of the resonant converter, and the optimal design of the resonant tank is also proposed. In order to detect resonant destruction, a detection method formulated by analyzing the resonant current peak value for the load capacity is proposed. The algorithm proposed in this paper is verified by simulation and experiment.

Polyvinylidene Fluoride‐Based Vibration Energy Harvester with Piezoelectric and Electromagnetic Effects

Vibration energy harvesting technology aims to convert mechanical energy into electrical energy through piezoelectric effect or electromagnetic induction to supply energy for wireless sensors. Herein, based on polyvinylidene fluoride, a vibration energy harvester who couples piezoelectric effect and electromagnetic induction is proposed, and its performance of energy harvesting is studied from the aspects of multiphysical field, microscale, and energy harvesting circuit. First, a mass‐spring‐damper model is established from the dynamic point of view, and the equivalent circuit models of piezoelectric unit and electromagnetic unit are established from the electrical point of view. Second, the effects of the nonlinear magnetic field, temperature, and microvolume on the resonant frequency and output power density of the energy collector are analyzed by simulation. Finally, a piezoelectric electromagnetic composite energy harvesting circuit is designed and the output voltage rectifying and stabilizing with high electromechanical conversion efficiency is realized. The results show that the harvester realizes the expected functions of inputting alternating current and outputting direct current, with open circuit output voltage up to 6.55 V and output power up to 2.21 mW. This study provides a valuable reference for the research in the field of vibration energy harvesting.

Modern Advances in Magnetic Materials of Wireless Power Transfer Systems: A Review and New Perspectives.

The magnetic coupling resonant wireless power transfer (MCR-WPT) system is considered to be the most promising wireless power transfer (WPT) method because of its considerable transmission power, high transmission efficiency, and acceptable transmission distance. For achieving magnetic concentration, magnetic cores made of magnetic materials are usually added to MCR-WPT systems to enhance the coupling performance. However, with the rapid progress of WPT technology, the traditional magnetic materials gradually become the bottleneck that restricts the system power density enhancement. In order to meet the electromagnetic characteristics requirements of WPT systems, high-performance Mn-Zn and Ni-Zn ferrites, amorphous, nanocrystalline, and metamaterials have been developed rapidly in recent years. This paper introduces an extensive review of the magnetic materials of WPT systems, concluding with the state-of-the-art WPT technology and the development and application of high-performance magnetic materials. In addition, this study offers an exclusive reference to researchers and engineers who are interested in learning about the technology and highlights critical issues to be addressed. Finally, the potential challenges and opportunities of WPT magnetic materials are presented, and the future development directions of the technology are foreseen and discussed.

Constant frequency resonant inductive wireless power transfer link with load-independent voltage output - a generalized approach

A closed-form analytical expression is derived in the paper, linking five parameters (coil inductances, compensating capacitor values and coupling coefficient) of a typical series-series compensated resonant inductive wireless power transfer link (WPTL) with given operating frequency so that the output voltage remains load independent. It is shown that for a given operating frequency, infinite amount of compensation capacitor pairs exists, yielding load independent voltage gain. Feasible solutions range is determined and it is demonstrated that two commonly used operation points are particular cases of the proposed generalized design expression. Intuitive explanation based on generalized loosely coupled transformer model is also provided.