Showing papers on "RLC circuit published in 2018"

Maximum Energy Efficiency Operation of Series-Series Resonant Wireless Power Transfer Systems Using On-Off Keying Modulation

Abstract: Maximum energy efficiency in wireless power transfer (WPT) systems can be achieved through the use of magnetic resonance technique at a certain load resistance value However, practical load resistance is not constant Previously, a switched mode dc–dc converter was used in the receiver circuit to emulate an equivalent load resistance for maximum energy efficiency In this paper, a new approach based on the On–Off Keying is proposed to achieve the high energy efficiency operation over a wide range of load power without using an impedance-matching dc–dc power converter This simple and effective method has reduced average switching frequency and switching losses It can be applied to any series-series resonant WPT system designed to operate at a constant output voltage Practical measurements have confirmed the validity of the proposal

Integrated Half-Bridge CLLC Bidirectional Converter for Energy Storage Systems

Abstract: This paper proposes an integrated half-bridge CLLC (IHBCLLC) resonant bidirectional dc–dc converter suitable as an interface between two dc voltage buses in various applications including energy storage systems. This converter is an integration of a half-bridge CLLC resonant circuit and a buck/boost circuit. Compared with the traditional pulse frequency modulation and phase-shift controlled CLLC resonant converter, for the proposed convertor, the high voltage gain can be obtained from pulse width modulation. Synchronous pulse width modulation is adopted for the converter, and the switching frequency is equal to the resonant frequency. The CLLC resonant circuit can help MOSFETs to achieve soft switching and high voltage gain. The simulation analysis of the modulation schedule and operating principle of the proposed converter prove that the converter is able to achieve zero-voltage switching or zero-current switching. Experimental results obtained from a 1-kW converter prototype confirm the theoretical analysis and the simulation results.

High-Frequency EMI Attenuation at Source With the Auxiliary Commutated Pole Inverter

Abstract: Fast-switching power converters are a key enabling technology for the more electric aircraft (MEA), but the generated electromagnetic interference (EMI) poses significant challenges to the electrification effort. To meet the stringent aerospace EMI standards, passive filters are commonly employed, despite the weight and size constraints imposed by the MEA. Alternatively, the EMI source, i.e., the high $dv\text{/} dt$ and $di\text{/} dt$ slew rates, can be addressed through waveform-shaping techniques. For example, while most soft-switching converters can reduce switching loss, they do so by switching the semiconductor devices in a slower and smoother manner, resulting in the attenuation of high-frequency harmonics. This paper examines the auxiliary commutated pole inverter (ACPI) topology, and its first contribution is the attenuation of the high-frequency content of its EMI source, that is, the output voltage, in a predictable manner, through the active control of the resonant circuit. This is achieved by first, discussing the time-domain characteristics of trapezoidal and S-shaped pulse-trains that lead to attenuated high-frequency harmonic content, and second, by analyzing the equivalent LC circuit of the ACPI. The design of the inverter is then focused on the active control of the resonant parameters, for a predetermined and enhanced output voltage high-frequency response. The second contribution of this paper is the comparison of the EMI performance of hard switching and of three soft-switching modes, fixed-timing control, variable-timing control, and capacitive turn- off s, and how this informs important metrics such as power efficiency, current stress, and implementation complexity. Finally, the third contribution is on the trade-offs that arise when the primary design goal is enhanced EMI performance as opposed to switching loss reduction. A 5-kW, 3-phase ACPI prototype is used for validating the high-frequency content attenuation at source. It is shown that the ACPI can achieve a 37 dB harmonic attenuation of its output voltage at 4 MHz, compared to a hard-switched inverter.

Analysis and Design of Zero-Current Switching Switched-Capacitor Cell Balancing Circuit for Series-Connected Battery/Supercapacitor

Abstract: To overcome the problem that the balancing performance of existing switched-capacitor (SC) cell balancing systems drops along with the increase in the number of series-connected battery cells, a novel SC cell balancing circuit is presented in this paper. The same as other SC balancing systems, only a pair of complementary square-wave signals is required to control the proposed circuit. With resonant SC design, all switches employed in the proposed balancing circuit operate under zero-current switching. The equivalent model is derived to reveal the balancing performance of the proposed balancing circuit. The system feasibility and theoretical analysis are verified by both of simulation and experimental results.

A Novel Soft-Switching Interleaved Coupled-Inductor Boost Converter With Only Single Auxiliary Circuit

Abstract: A novel soft-switching interleaved coupled-inductor boost converter is proposed in this paper. Only a single active soft-switching module is needed to simultaneously achieve the soft-switching property of the two switches in the interleaved coupled-inductor boost converter. The better efficiency is achieved with the less components and cost. The two main switches can achieve the ZVT turn-on and smaller-current turn-off simultaneously when the single active soft-switching module is active. Due to the coupling characteristic of the inductors, the voltages across the two inductors are changed at the same time; therefore, the equivalent circuit is equal to the parasitic capacitors of the two main switches in parallel to resonate with the auxiliary inductor. By coupling two input inductors, the volume and cost of the circuit can be reduced. The interleaved coupled-inductor topology can also reduce the input and output current ripples and share the input and output currents. The operating modes, analysis, and design of the proposed circuit have been discussed in this paper. Simulation and experiments are finally conducted to verify the validity of the proposed circuit.

Magnetic-free radio frequency circulator based on spatiotemporal commutation of MEMS resonators

Abstract: This paper reports on the first demonstration of a magnetic-free radio-frequency (RF) Microelectromechanical Resonant Circulator (MIRC). For the first time, magnetic-free non-reciprocity is achieved by imparting an effective angular momentum bias to a MEMS resonant circuit. The angular momentum is efficiently realized through spatiotemporal modulation of three strongly coupled high-Q (>1000) Aluminum Nitride (AlN) Contour Mode MEMS Resonators (CMRs) with signals of the same magnitude and phase difference of 1200. Differently from previous demonstrations based on varactor-based frequency modulation of low-Q LC networks, in this work the spatiotemporal modulation of the high-Q MEMS resonators is implemented by means of switched capacitors which minimizes the complexity of the modulation network, increases the modulation efficiency and mitigates the fundamental linearity limitations associated with solid-state varactors. Furthermore, due to the high Q of the MEMS resonators employed, strong non-reciprocity is achieved with an ultra-low modulation frequency of ∼120 kHz (∼0.08% of the RF frequency, orders of magnitude lower than previous demonstrations) which directly enables a total power consumption of only ∼38 μW which, to the best of our knowledge, is the lowest ever reported for magnetic-free RF circulators based on temporally modulated circuits.

Second-Order Equivalent Circuits for the Design of Doubly-Tuned Transformer Matching Networks

Abstract: The doubly-tuned magnetic transformer, comprising coupled inductors shunted by capacitors, is today widely in use as interstage network and for impedance matching in silicon millimeter waves amplifiers. It provides several advantages, compared with simple LC resonators, but the design is made complex by the high order of the network, featuring multiple resonances, and by the large number of components to be selected. In this paper, a novel approach for the analysis and design of such a network is proposed. It is shown that the response can be very well approximated, in the neighborhood of each resonance frequency, by a second-order parallel or series RLC equivalent circuit. This yields simple equations for the impedance, the bandwidth, and the power loss, giving intuition into the network behavior, and greatly simplifying the design. Based on the results of the analysis, guidelines for the network optimization are proposed, targeting minimum power loss and a flat broadband response. Design examples of practical interest are presented: the component values estimated by hand calculation are in very good agreement with those provided by a numerical circuit optimizer.

Evaluation of High-Frequency Circuit Models for Horizontal and Vertical Grounding Electrodes

Abstract: Circuit models of horizontal and vertical grounding electrodes are traditionally used in high-frequency (HF) analysis, although underlying approximations limit their accuracy in some low-frequency ranges. Recently, a number of new circuit models have been introduced, but the improvement of the accuracy at HF has not been systematically evaluated. In this paper, we show that new circuit models can be directly derived from method of moments solutions of the integral forms of Maxwell equations by introducing different assumptions. This approach helps to categorize different models into only a few categories based on underlying approximations. To determine the applicable range, we analyze the error for impedance to ground computed by different circuit models in comparison to that calculated by a rigorous full-wave model over wide ranges of parameters, such as electrode length, soil resistivity, and frequency. This paper: 1) provides a parametric analysis that enables the estimation of the applicability of the particular circuit model for application to a practical case based on its accuracy; 2) presents a unified systematic approach to derive circuit models with different capabilities; and 3) reveals that the modeling of the mutual coupling between different parts of the grounding electrode is the key factor for radically improving the accuracy of circuit models at HF.

A wirelessly-controlled piezoelectric microvalve for regulated drug delivery

Abstract: This paper reports a novel wireless control of a normally-closed piezoelectric microvalve activated by a wireless inductor-capacitor (LC) resonant circuit, and enabled by an external magnetic field. The LC circuit is formed by connecting a multilayer coil to a piezoelectric actuator (PEA) that behaves as a capacitor and a resistor in parallel. The LC circuit is activated by modulating the field frequency to its resonant frequency ( fr ) of 10 kHz, which matches the optimal operating frequency of the device, while considering the resonant frequency of the PEA. The working fluid is stored in an 88.9 μL polydimethylsiloxane balloon reservoir that pumps the liquid due to the difference in pressure, which eliminates the need for a pump. The design of the device was optimized using several analytical and experimental approaches. This device was fabricated using a time and cost-effective out-of-clean-room fabrication process. The valving performance was initially characterized in air, then in phosphate buffered saline (PBS) solution to mimic the drug release kinetics into human interstitial body fluids. Maximum flow rate values of 8.91 and 7.42 μL/min are achieved in air and PBS solution respectively, at a maximum input pressure value of ∼13 kPa. A programmed short-term delivery of desired liquid volumes in separate batches shows that the volumes are delivered into air and PBS solution with maximum percentage errors of 7.49% and 7.91%, respectively. Additionally, a programmed 3-day long-term reliability test shows that the device was able to achieve desired flow rate values between 160 and 320 μL/day in air and PBS solution with a maximum percentage error of 3.11% and 4.39%, respectively. The results show that the developed device has high potential to be used in drug delivery applications.

Optimized Power Modules for Silicon Carbide mosfet

Abstract: A new 3-D power module dedicated to SiC mosfet is presented. It is based on printed circuit board embedded die technology and is compared with a standard power module. After considering the characteristics that contribute to optimal switching performances from the packaging point of view, both modules are characterized in terms of switching behavior and electromagnetic interference emissions. The results show better performances of the 3-D embedded die module with stray inductances below 2 nH and two times less common mode noise.

A Passive Design Scheme to Increase the Rectified Power of Piezoelectric Energy Harvesters

Abstract: Piezoelectric vibration energy harvesting is becoming a promising solution to power wireless sensors and portable electronics. While miniaturizing energy harvesting systems, rectified power efficiencies from miniaturized piezoelectric transducers (PTs) are usually decreased due to insufficient voltage levels generated by the PTs. In this paper, a monolithic PT is split into several regions connected in series. The raw electrical output power is kept constant for different connection configurations, as theoretically predicted. However, the rectified power following a full-bridge rectifier (FBR), or a synchronized switch harvesting on an inductor (SSHI) rectifier, is significantly increased due to the higher voltage/current ratio of series connections. This is an entirely passive design scheme without introducing any additional quiescent power consumption, and it is compatible with most of the state-of-the-art interface circuits. Detailed theoretical derivations are provided to support the theory, and the results are experimentally evaluated using a custom microelectromechanical system PT and a complementary metal–oxide–semiconductor rectification circuit. The results show that, while a PT is split into eight regions connected in series, the performance while using an FBR and an SSHI circuit is increased by 2.3 $\times$ and 5.8 $\times$ , respectively, providing an entirely passive approach to improving energy conversion efficiency.

A Damping Scheme for Switching Ringing of Full SiC MOSFET by Air Core PCB Circuit

Abstract: In this paper, a resonant damping circuit to suppress the switching ringing of full SiC mosfet is proposed. It reveals that the ringing phenomenon caused by parasitic impedances of switching circuit can be damped out using air core PCB transformer which has a properly designed secondary side circuit. The design method for PCB transformer and the secondary circuit are developed considering the physical dimension applied to the PCB transformer inserted between full SiC mosfet module and snubber capacitor. Experimental results using 1200 V–180 A full SiC mosfet module validate the design method and the performance of the proposed air core PCB circuit. Thanks to the damping circuit, the resonant component due to the switching ringing has been reduced to a half compared to that of system without damping circuit.

Theory of Double Ladder Lumped Circuits With Degenerate Band Edge

Abstract: A conventional periodic LC ladder circuit forms a transmission line that has a regular band edge between a passband and a stopband. Here for the first time, we develop the theory of simple yet unconventional double ladder circuit that exhibits a special degeneracy condition referred to as a degenerate band edge (DBE). The degeneracy occurs when four independent eigenstates coalesce into a single eigenstate at the DBE frequency. In addition to possible practical applications, this circuit may provide insight into DBE behavior that is not clear in more complex systems. We show that double ladder resonators exhibit unusual behavior of the loaded quality factor near the DBE, leading to a stable resonance frequency against load variations. These two properties in the proposed circuit are superior to the analogous properties in single ladder circuits. Our proposed analysis leads to analytic expressions for all circuit quantities thus providing insight into the very complex behavior near degeneracy points in periodic circuits. Interestingly, here we show for the first time That a DBE is obtained with unit cells that are symmetric along the propagation direction. The proposed theory of double ladders presented here has potential applications in filters, couplers, oscillators, and pulse shaping networks.

LED Driver Based on Boost Circuit and LLC Converter

Abstract: In order to reduce the size and cost of a medium-power light-emitting diode (LED) driver, a novel single-stage LED driver integrating a boost converter with a half-bridge LLC resonant converter has been proposed. This topology is composed of a boost power factor correction circuit operating in a discontinuous conduction mode and an isolated LLC circuit unit with soft-switching characteristics. The proposed LED driver only adopted two switch components, thus benefiting from control simple and without employing an extra switch driver and a control circuit. The operating principle and characteristics of the proposed LED driver are analyzed in detail. In addition, experimental results of a laboratory prototype for supplying a 100-W/70-V LED lighting systems from 220-V/50-Hz ac line voltage are presented to verify well the correctness of the theoretical analysis and parameters’ design.

Optimizing Wireless Power Transfer From Multiple Transmit Coils

Abstract: The widespread need for ubiquitous power delivery is driving the commercialization of inductive wireless power transfer (WPT). Wireless power transfer systems, however, are plagued by low efficiency. To combat this, we propose a new approach to maximize the efficiency of inductive WPT using multiple coil charging systems. The use of multiple coils can potentially allow the system to efficiently adapt to magnetic field propagation conditions, similar to the way multiple antennas are used to adapt to channel conditions in wireless communication systems. We consider a multiple-input single-output WPT system using near-field inductive coupling. While such systems have been extensively studied in previous work using lumped resistance, inductance, and capacitance (RLC) circuit models to analyze their behavior, the difficulty of constructing tractable and realistic circuit models has limited the ability to accurately predict and optimize the performance of these systems. The main innovation in this paper is to take a more abstract approach to modeling the WPT system as a linear circuit whose input-output relationship is expressed in terms of a small number of unknown parameters that can be thought of as transimpedances and gains. The crucial advantage of this approach is the economy of the representation, i.e., the number of unknown model parameters can be much smaller than the number of lumped circuit elements required for a complete and accurate RLC circuit representation. We present simple derivations for the optimal voltage excitations to be applied at the transmitters to maximize power transfer efficiency as well as suboptimal excitations which are less computationally intensive. A simple procedure, which we call circuit sounding, for estimating the unknown parameters using a small set of direct measurements is described. We outline a series of experiments with four transmit coils and two receive coils that verify the model and show that the optimal solution can achieve higher efficiencies than those of previously known methods.

A Power-Frequency Controller With Resonance Frequency Tracking Capability for Inductive Power Transfer Systems

Abstract: A self-tuning controller for power transfer regulation in inductive power transfer (IPT) systems is proposed in this paper. The controller enables power transfer regulation around a user-defined reference power level. The converter's efficiency is improved by constantly tuning the switching operations to the resonant current, thereby achieving the soft-switching operations reducing electromagnetic interference in the power converters. The self-tuning capability makes it ideal for dynamic IPT systems with uncertain loads and fluctuating resonance frequency. High operating frequencies can be achieved using the simplified digital circuit design for the controller, proposed in this paper, which delivers a low total propagation delay. Bidirectional power transfer can be enabled by using the proposed controller on both transmitter and receiver sides. In the reverse power flow mode, the primary converter operates as a rectifier and the power transfer is controlled through the secondary converter using the proposed controller. The performance of the proposed controller is analyzed using MATLAB/Simulink and the results are presented. Finally, the proposed controller is implemented experimentally and its performance is evaluated as a case study on an IPT system. The experimental and simulation results conform to each other, and show that the proposed converter can effectively regulate the power transfer with an improved efficiency.

A Comprehensive Study on Composite Resonant Circuit-Based Wireless Power Transfer Systems

Abstract: In the magnetic resonant wireless power transfer (WPT) technology, system topology is the main factor that determines the WPT characteristics of the system, and recently, various system topologies based on various composite resonant circuits are being applied in WPT applications. This paper groups the composite resonant circuit-based WPT systems into one family and conducts a comprehensive investigation on their topologies and characteristics. First, characteristics of the composite resonant circuits, which are the fundamental circuits of transmitter and receiver of these systems, are investigated; in the process, a calculation method of resonant frequency, current ratio, and quality factor of these circuits are presented and the characteristics of these parameters are clarified. Second, based on that, the composite resonant circuit-based WPT systems are investigated. Possible topologies of these systems are explored and an equivalent system model of these systems is proposed. Based on that, characteristics evaluation expressions of these systems are derived and the optimal design guide of these systems is discussed. Finally, experimental prototypes are constructed and the proposed theory is verified by experiment results.

Frequency extension circuit for EER transmitters operating with electrically short antennas

Abstract: Modern high-efficiency EER transmitters to comply with the standards for electromagnetic compatibility require very precise matching with the load. The antennas used on board are often electrically short and therefore narrow-banded. Traditional LC-matching in some cases can not provide the required level of SWR. A method for matching electrically short narrow-band antennas with the help of RLC-circuits is proposed. It allows providing the required SWR value of the load not more than 1.05 in the band of the OFDM signal of 10 kHz and not more than 1.1 in the band of 20 kHz. A technique for designing a RLC frequency extension circuit is developed. The carried out analysis of the energy efficiency of the frequency extension circuit showed that if the antenna 3-dB bandwidth exceeds 10 kHz, the losses in the FEC do not exceed 1 dB. The developed method for calculating the frequency extension circuit was tested for Digital Radio Mondiale (DRM) LW broadcasting stations. The possibility matching of existing antennas with a height of 257 meters for the DRM mode with 9/10 kHz signal bandwidth over the entire range of LW is shown. Also, the potential for using Simulcast mode with a dual signal bandwidth is shown: for the upper half of the low-frequency range, with antennas 257 meters high and 378 meters for the lower one.

Double Pile-Up Resonance Energy Harvesting Circuit for Piezoelectric and Thermoelectric Materials

Abstract: This paper presents a double pile-up resonance energy harvesting circuit that efficiently and simultaneously extracts energy from a piezoelectric transducer (PZT) and a thermoelectric generator. The proposed harvester operates in a double pile-up mode (DPM) to efficiently extract energy from PZT with the enhanced damping force, resulting in a 1452% improvement in power extraction, which is the best performance among the state-of-the-art works. The harvester also operates in a boost converter mode (BCM) without an additional power switch, achieving 75% conversion efficiency at 450- $\mu \text{W}$ output power. With a single-shared inductor, a simple control scheme enables the harvester to operate in both DPM and BCM by time-multiplexing method, consuming a low quiescent current of 240 nA. The prototype chip fabricated in a 0.18- $\mu \text{m}$ BCD occupies an area of 1.5 mm $\times $ 1 mm, and it was tested with a 20-nF PZT product (PPA-1001) vibrated by a shaker (Type 4810).

Differentiation and Passivity for Control of Brayton-Moser Systems

Abstract: This paper deals with a class of Resistive-Inductive-Capacitive (RLC) circuits and switched RLC (s-RLC) circuits modeled in Brayton Moser framework. For this class of systems, new passivity properties using a Krasovskii's type Lyapunov function as storage function are presented. Consequently, the supply-rate is a function of the system states, inputs and their first time-derivatives. Moreover, after showing the integrability property of the port-variables, two simple control methodologies called output shaping and input shaping are proposed for regulating the voltage in RLC and s-RLC circuits. Global asymptotic convergence to the desired operating point is theoretically proved for both proposed control methodologies. Moreover, robustness with respect to load uncertainty is ensured by the input shaping methodology. The applicability of the proposed methodologies is illustrated by designing voltage controllers for DC-DC converters and DC networks.

Analytic solutions of fractional differential equation associated with RLC electrical circuit

Abstract: In the present article, we derived the solution of a fractional differential equation associated with a RLC electrical circuit with order 1 < a ≤ 2 and 1 < b ≤ 1. The Sumudu transform technique is ...

A topology optimization formulation for transient design of multi‐entry laminated piezocomposite energy harvesting devices coupled with electrical circuit

Abstract: Summary Laminated piezocomposite energy harvesters (LAPEHs) are multilayer arrangements of piezoelectric and non-piezoelectric materials. Multiple materials and physics, and dynamic analysis need to be considered in their design. Usually these devices are designed for harmonic excitation, however, they are subjected to other types of excitations. Thus, a novel topology optimization formulation is developed for designing LAPEHs that considers a combination of harmonic and transient optimization problems with the aim of designing the so-called “multi-entry" devices in which the power generated is the same for different types of excitation. LAPEHs are modeled by the finite element method (FEM) and the material model used for the piezoelectric layer is based on penalization and polarization model (PEMAP-P) who controls material distribution and corresponding polarization. To optimize the RLC circuit, a novel linear interpolation model of coupled electrical impedance (LIMCEI) is also introduced to consider different magnitudes of the coupled impedance. The topology optimization problem seeks to maximize the active power generated by the LAPEH at its RLC circuit, to minimize its response time measured as the slope of the power versus time curve, and to maximize its stiffness. Numerical examples are shown in order to illustrate the potential of the method. This article is protected by copyright. All rights reserved.

A Self-Tuning Resonant-Inductive-Link Transmit Driver Using Quadrature Symmetric Delay Trimmable Phase-Switched Fractional Capacitance

Abstract: The efficiency of inductively coupled power transfer systems is increased when high- $Q$ inductor–capacitor circuits are used, maximizing the magnetic field strength at the transmitter for a given drive amplitude. Such circuits require precise tuning to compensate environmental effects and component tolerances, which modify the resonant frequency. A single zero-voltage-switched fractional capacitance may be used to accurately tune the circuit to resonance, reducing implementation costs compared with classical tuning techniques. However, integration into a chip presents challenges, which must be addressed, such as operating with large voltage excursions and compensating for high-voltage driver delays. We describe here the operation of a self-tuning $LC$ resonant circuit driver using a symmetrically switched fractional capacitance. An architecture for a fully integrated system for operation at 75 kHz–2.6 MHz is presented. Implemented in a 0.18- $\mu \text{m}$ 1.8–50 V CMOS/laterally diffused MOSFET(LDMOS) technology, the integrated circuit uses high-voltage interfaces for capacitance switching and sampling inputs and includes digital phase trimming to compensate propagation delays in large driver devices. Correct operation of the self-tuning functionality is verified across the available frequency range, with results presented for static and dynamic tuning responses.

A 15-mV Inductor-Less Start-up Converter Using a Piezoelectric Transformer for Energy Harvesting Applications

Abstract: This paper presents an inductor-less start-up converter for a sub-100-mV energy harvester based on an Armstrong oscillator topology using a piezoelectric transformer and a normally ON MOSFET. Two models of the converter have been detailed and validated experimentally for the start-up phase and steady-state operation to, respectively, determine the minimum start-up input voltage and the voltage gain. The models have been validated experimentally in a setup associating the converter and a thermoelectric generator. Based on a Rosen-type piezoelectric transformer and off-the-shelf components, the proposed start-up topology begins to oscillate at 15 mV and achieves a 1-V output voltage at only 43 mV. Compared to the literature, the topology needs no inductive component and achieves self-starting operation with a smaller input voltage.

Wideband, Non-Foster Impedance Matching of Electrically Small Transmitting Antennas

Abstract: Electrically small antennas (ESAs) can be passively matched only over very narrow bandwidths and the resulting antennas have low gains. These are the major limiting factors for ESAs used in transmit applications, especially at high-frequency (HF) and lower Very HF frequency bands. This paper discusses the challenges of transmit ESA matching circuit design and the design process of a new non-Foster transmit matching architecture for electrically small monopole antennas that achieves wide bandwidth, high transmission efficiency (transducer power gain), and stability at the same time. The proposed circuit is composed of a current buffer (for high isolation), a transformer (for real-part matching), and a negative impedance converter (for imaginary-part matching). The measured −6 dB (−10 dB) $|S_{11}|$ fractional bandwidth of the proposed non-Foster transmitting system is 110% (39%), while the maximum bandwidth that can be achieved is 0.076% (0.047%) when matched with the conventional passive matching. The transmission efficiency of the system is improved by as much as 34.4 dB compared to the same antenna without the proposed non-Foster matching circuit, and it retains an enhanced efficiency over the entire frequency band of operation (26–89 MHz). The system remains stable within this frequency band. The measurement results of the compact and broadband transmitting antenna prototype verify the design concept.

Design of High Efficiency Broadband Continuous Class-F Power Amplifier Using Real Frequency Technique With Finite Transmission Zero

Abstract: In this paper, a new methodology using a distributed ladder structure with finite transmission zero at finite frequencies is proposed for designing a broadband high-efficiency continuous Class-F (CCF) power amplifier (PA). The approach of realizing finite transmission zeros in Richard domain using Real Frequency Technique is first presented. By applying the proposed approach, the characteristics of the driving point impedance (DPI) of the proposed structure can be deduced and obtained in theory. Furthermore, the synthesis methods in Richard domain are extended to synthesize the DPI of the proposed structure. Four types of distributed elements are investigated to synthesize the DPI of the proposed structure. This proposed structure can improve the performance of the CCF PA when the bandwidth approaches an octave as the finite transmission zero can be used to control the second harmonic impedance of the lower frequency which is near the upper frequency of the operation band. To verify the validity of the proposed method, a broadband high-efficiency CCF PA working from 1.15 to 2.2 GHz is designed. Experimental results show that the fabricated PA achieves 11.3–13.7 dB power gain and 40.5–43.2 dBm output power in the operation band. And the PA has also achieved a high-efficiency characteristic of 70%–83% drain efficiency (DE) over the whole operation bandwidth.

Impact of Transformer Leakage Inductance on the Soft-Switching Solid-State Transformer

Abstract: Leakage inductance is inevitable in high frequency (HF) transformer design for solid-state transformer applications. Managing the energy trapped in leakage is very crucial for a safe and efficient operation of Solid-State Transformer (SST) converters. In the soft-switching solid-state transformer (S4T), leakage energy management is achieved in a passive way by having it absorbed in the two auxiliary resonant circuits, one on each side of the HF transformer. However, this could lead to an additional voltage/current stress on the resonant circuit and could impact various elements of the S4T design. This paper presents a detailed analysis of the resonant circuit operation and analytically derived relations between the leakage inductance and the peak voltage/current stress in the S4T converter. Simulation and experimental results verifying the analysis are presented. Using the derived relations, the design considerations for the S4T resonant circuit parameters are also discussed.

A Passive PEEC-Based Micromodeling Circuit for High-Speed Interconnection Problems

Abstract: A passive partial element equivalent circuit (PEEC)-based micromodeling circuit is proposed for time-domain simulation of a high-speed interconnection problem. This physics-based model order reduction method derives a concise and physically meaningful circuit model from the PEEC model by absorbing its insignificant nodes. To maintain high fidelity of the original electromagnetic PEEC model, the concept of pseudoinductor is introduced to the node-absorbing process. The derivation process does not involve any matrix inversion or decomposition and is highly suitable for GPU parallel computations. Passivity of the micromodeling circuit is ensured by a new passivity checking and enforcement method proposed for the first time. As the scale of the micromodeling circuit can be one order of magnitude smaller than that of the original PEEC model, the time-domain simulation can be three orders of magnitude faster. Two practical examples are given to demonstrate the high fidelity, scalability, and accuracy of the proposed micromodeling circuit, showing excellent applicability to high-speed interconnection problems.

Experimental and Modeling Comparison of Different Damping Techniques to Suppress Switching Oscillations of SiC MOSFETs

Abstract: The switching oscillations associated with the ultrafast switching characteristics of silicon carbide (SiC) MOSFETs seriously limit the potential of high frequency and high power density applications. To understand and mitigate this behavior, it is critical to analyze and compare different damping techniques for the oscillation suppression. This paper presents a simple RLC circuit model for SiC MOSFET turn-off switching oscillation, where the mitigation design guidelines are provided based on modeling analysis. The calculation, simulation and experimental results indicate that the switching oscillations can be properly controlled with the methods presented in this work. It is observed that the RC snubber and ferrite bead techniques offer more effective damping solution than the gate driver slowdown or extra gate resistor approaches.

A Resistor-Free Absorptive Common-Mode Filter Using Gap-Coupled Resonator

Abstract: This letter proposed a resistor-free absorptive common-mode filter (A-CMF). Also, a novel methodology of CM noise absorption is introduced. By making use of the dielectric loss of printed circuit board (PCB), CM noise is absorbed in the proposed A-CMF at 2.45 GHz without using surface-mount resistors. In this letter, an equivalent circuit model is built, analyzed, implemented, and fabricated on a four-layer PCB. Finally, the measured results are compared with the simulated ones, where a very good agreement can be found.