LC Resonant Tank Research Articles

Noncirculating current series resonant converter with pulse frequency modulation

SummaryIn this paper, an asymmetric pulse frequency modulation (APFM) is applied to the full‐bridge series resonant converter with a secondary LC resonant tank. Different from the traditional PFM, the upper and lower switches have complementary gate drivers and the lower switches have constant on time of half‐resonant period in this paper. Thanks to the resonant tank moved to the secondary side with the adopted APFM, the maximum magnetic flux density Bm of a high‐frequency transformer (HFT) is only concerned with the fixed resonant frequency rather than the variable switching frequency. Hence, the switching frequency can be widely regulated, as well as the voltage gain. Furthermore, the circulating current flowing back to the input voltage source in the traditional LC series resonant converter can be eliminated by the APFM, leading to a low resonant current peak value. The operation principles and characteristics of the adopted method are analyzed in detail. Finally, a 500 W/70–120 V to 300 V/21–180 kHz prototype is built, and the experimental results verified the theoretical analysis well.

Investigation of Paralleled Inverters With Various-Order LC Resonant Tanks for Possible Surface Treatment Applications

Investigation of Paralleled Inverters With Various-Order LC Resonant Tanks for Possible Surface Treatment Applications

A 0.45‐V low‐power low‐noise amplifier using a wideband image‐rejection technology

AbstractA 0.45‐V low‐power wideband image‐rejection low‐noise amplifier (LNA) using Taiwan Semiconductor Manufacturing Company (TSMC) 0.18‐μm CMOS process has been proposed. The supply voltage, power consumption and chip area of the proposed LNA can be reduced using forward body biasing, folded cascode topology and a feedback capacitor. Moreover, a wideband gain‐enhancement‐and‐image‐rejection (WGEIR) circuit including a variable resonant LC tank and a common‐gate amplifier has been developed. The inductance of the variable resonant LC tank can enlarge the gain of the proposed LNA. The capacitance of the variable resonant LC tank can achieve the image rejection. Using the WGEIR circuit, gain enhancement and wideband image rejection can be achieved simultaneously. The variable inductors and capacitors are developed for suppressing wideband image signals and good image rejection ratio (IRR). The combination of the variable inductors and capacitors can achieve eight image‐reject frequencies under three control voltages. The proposed LNA shows the measured results including a 10‐dB power gain, a 3‐dB noise figure (NF) and a −11‐dBm input third‐order intercept point (IIP3) at 2.4 GHz, respectively. The measured IRR ranges from 18 to 23 dBc around 3.6–4.5 GHz, which is 900‐MHz image‐reject bandwidth. The measured proposed LNA using the mentioned techniques consumes 0.8‐mW power.

3-D Printed Microfluidic Coils With Liquid Metal for Wireless Motion Sensing

Wearable and compliant metallic coils are gaining importance in applications such as healthcare, internet of things etc. for sensing and wireless power and data transfer. This paper presents a resource-efficient and low-cost additive manufacturing (AM) based microfluidic coils filled with flexible and stretchable liquid metals. The fabrication process involves two main steps: (i) printing of the microfluidic capillaries using a stereolithographic 3D printer, and (ii) filling the channels with eutectic Gallium-Indium-Tin. We printed the transmitter and receiver coils (resistances 3-5 Ω) and demonstrated wireless power transfer between them with a resonant LC tank circuit. Furthermore, wireless motion sensing is shown with the movement of receiver coil in both horizontal and vertical direction. For vertical motion detection, the peak of the FFT signal varies linearly when the coils are separated with steps of 1 mm giving a sensitivity of 1dBV/mm. The presented approach could extend to develop flexible and squishy metal coils for applications in various fields such as wearable and implantable electronics, soft robotics, and medical instruments.

Design and analysis of isolated high step-up Y-source DC/DC resonant converter for photovoltaic applications

ABSTRACT This paper presents the design and analysis of an isolated high step-up Y-source DC/DC converter for photovoltaic systems. At high switching frequencies, the conventional impedance source converter (ISC) experiences higher switching losses. To mitigate this, a high gain soft-switched frequency-modulated Y-source DC/DC converter is proposed. Here, soft switching is implemented on the Y-source impedance converter by creating quasi-resonance during a shoot-through instant. Thus, quasi-resonance occurs by an LC resonant tank, and it is formed using a resonant capacitor and leakage inductance of a transformer. It ensures that all the active switches are turned off with zero current switching (ZCS) and the voltage stress on each switch is much lower than the output voltage with lower turn-off voltage spikes. Thus, it eliminates the need for a snubber circuit. The output voltage is regulated by frequency modulation with the ON period of all four active switches kept constant. The converter can also deliver a continuous input current (CIC) and high voltage gain with a small shoot-through duty ratio . The galvanic isolation of the converter helps to eliminate the leakage current issues and safety hazards faced by the non-isolated counterparts. The proposed topology has all the inherent characteristics of a typical impedance source DC/DC converter with higher conversion efficiency over a wide range of output loads. The proposed converter achieves 96.46% of full load efficiency. Finally, a 200W prototype is built and tested in the laboratory to verify the converter design and performance.

Battery Internal Temperature Measurement Using LC Resonant Tank for Battery Management Systems

This paper suggests an embedded battery impedance measurement based on an Inductor Capacitor (LC) resonant tank to measure the battery’s internal temperature for battery management systems (BMS). The purpose of the BMS is to provide state-of-charge (SoC) balancing and the preheating mechanism at sub-zero temperatures. Battery Impedance Spectroscopy (BIS) for battery internal temperature measurement is achieved by an LC resonant tank connected to the batteries in parallel to induce created resonant current and voltage into the battery. The peaks of the voltage and current waveforms are measured and recorded. Then, the resistance of the battery can be calculated by comparing the peak voltage and current waveforms. Since the resistance of the battery is affected by the battery’s internal temperature, the internal temperature of the battery can be estimated. The benefit of using the LC tank for the battery’s internal temperature is to reduce data processing since no window and Fast Fourier Transform (FFT) is needed for this method. In addition, the proposed method measures the battery’s internal temperature without any internal or external temperature sensor. Power Simulation (PSIM) simulation software is used in this proposed method. Panasonic batteries 18650 and a dSPACE DS1104 are used for the experiment to verify the proposed method. The proposed method shows that the LC resonant tank can measure three batteries B1, B2, and B3 internal resistance with 17.87%, 18.14%, and 17.73% errors compared to the Frequency Response Analyzer (FRA). In addition, the total time needed for balancing is 400 s, and the total energy consumed by the preheating mechanism is 0.214%/°C to preheat the lithium-ion batteries (LIBs) from −5 °C to 10 °C.

Advanced Modulation Scheme of a Dual-Active-Bridge Series Resonant Converter (DABSRC) for Enhanced Performance

This paper proposes a two-degree-of-freedom (2-DoF) modulation technique for the efficient optimization of an open-loop three-phase dual-active-bridge series resonant converter (3P-DABSRC). The efficiency and performance of an conventional dual-active-bridge (DAB) converter decrease when it is operated over a wide range of voltage gain. The efficiency and performance of a DAB converter depend upon the switching and conduction losses. Circulating current is the main cause of conduction loss, and hard switching of active switches adds a switching loss. To increase the performance of DAB converters, the first objective is to minimize the conduction loss, and the second objective is to reduce the switching loss. Still, unfortunately, it is not easy to achieve these two objectives simultaneously. Circulating current helps us to reduce the switching loss, but the unbridled amount of circulating current will increase the root-mean-square inductor tank current, and as a result, the conduction loss will be increased. This paper presents an advanced modulation scheme for a 3P-DABSRC that can be used not only in low-power applications, but also in high-power applications. The DABSRC consists of a series LC resonant tank, isolated high-frequency transformer, and dual active bridge connected with the primary and secondary sides of the transformer. The proposed 2-DoF modulation technique not only minimizes the circulating current, but also eliminates the switching loss. Keeping the minimum phase shift between the primary and secondary bridges reduces the circulating current, and thus, all switches can be operated with zero-voltage switching (ZVS) for the entire power range. The power is controlled by changing the switching frequency from 45 to 63 kHz. To confirm the proposed topology and modulation scheme, a 1500 W DABSRC, which interfaces a 300 V DC bus with a 75 V DC bus, is simulated. A loss model of the proposed topology is also made to verify the results. The simulation results are used to confirm the proper operation of the 3P-DABSRC.

Backward Step-Up Control Strategy for Bidirectional LLC Resonant Converter

An LLC resonant converter has the advantages of simple structure and soft switching. It can enable bidirectional power transmission, but it is difficult to realize a normalized gain greater than one under backward mode (backward step-up mode). Cascaded dc/dc converters or topological changes can solve this problem, but additional switches and components are required and losses are added. Without changing the LLC resonant converter’s basic topology, this paper proposes a variable duty-cycle control strategy of primary side switches for backward step-up mode. Using variable duty-cycle control, the LC resonant tank can be charged, and then the backward step-up mode can be realized. Soft switching characteristics of some primary side switches and all secondary side switches are guaranteed. In this study, the working principle of an LLC resonant converter under bidirectional control strategy was analyzed, and the backward step-up control was analyzed in detail. The voltage gain and the boundary of continuous conduction mode (CCM) and discontinuous conduction mode (DCM) were derived. A synchronous rectification method related to the backward step-up control is proposed. The control strategy was verified by experiments.

Discussion and Analysis of Dumbbell Defect-Ground-Structure (DB-DGS) Resonators for Sensing Applications from a Circuit Theory Perspective.

Microstrip transmission lines loaded with dumbbell defect-ground-structure (DB-DGS) resonators transversally oriented have been exhaustively used in microwave circuits and sensors. Typically, these structures have been modelled by means of a parallel LC resonant tank series connected to the host line. However, the inductance and capacitance of such model do not have a physical meaning, since this model is inferred by transformation of a more realistic model, where the DB-DGS resonator, described by means of a resonant tank with inductance and capacitance related to the geometry of the DB-DGS, is magnetically coupled to the host line. From parameter extraction, the circuit parameters of both models are obtained by considering the DB-DGS covered with semi-infinite materials with different dielectric constant. The extracted parameters are coherent and reveal that the general assumption of considering the simple LC resonant tank series-connected to the line to describe the DB-DGS-loaded line is reasonable with some caution. The implications on the sensitivity, when the structure is devoted to operating as a permittivity sensor, are discussed.

Rotational Speed Measurement Based on LC Wireless Sensors.

This article presents a method for detecting rotational speed by LC (inductor-capacitor) wireless sensors. The sensing system consists of two identical LC resonant tanks. One is mounted on the rotating part and the other, as a readout circuit, is placed right above the rotating part. When the inductor on the rotating part is coaxially aligned with the readout inductor during rotation, the mutual coupling between them reaches the maximum, resulting in a peak amplitude induced at the readout LC tank. The period of the readout signal corresponds to the rotation speed. ADS (Advanced Design System) software was used to simulate and optimize the sensing system. A synchronous detection circuit was designed. The rotational speed of an electric was measured to validate this method experimentally, and the results indicated that the maximum error of the rotation speed from 16 rps to 41 rps was 0.279 rps.

Design of Low Phase Noise VCO Considering C/L Ratio of LC Resonator in 0.18-μm CMOS Technology

A voltage-controlled oscillator (VCO) is usually designed by maximizing the quality (Q-) factor of the LC-tank resonator to realize a low phase noise. For the same frequency, the ratio of C/L affects the loaded Q-factor (QL) and then phase noise of the VCO. This affect has not been considered so far in the design of VCO because the conventional on-chip spiral inductor cannot be optimized for C/L ratio. This brief first investigates the effects of C/L ratio on the phase noise, and a design methodology for optimized C/L ratio using defected ground structure (DGS) resonator is presented. Then, the resonators were further evaluated based on LgL-product simulation for a fixed Ibias. Employing the proposed resonator, a very low phase noise KUband VCO is designed and implemented in 0.18-lm CMOS technology. The measurement result shows that the proposed VCO has a phase noise of -110.77 dBc/Hz at 1 MHz offset of 17.5 GHz carrier frequency and a frequency tuning range of 8.7%. The VCO consumes 2.3 mW power, which results in a figure of merit (FoM) of -191.95 dB.

A Sawtooth MEMS Capacitive Strain Sensor for Passive Telemetry in Bearings

The development of economical and high-sensitive strain sensor is crucial for precise measurement of strain in industrial applications, such as bearings. During operation, bearing itself is a harsh environment, which usually has large temperature variations and large centrifugal forces. This paper presents a sawtooth MEMS capacitive strain sensor for passive telemetry in bearings. The interdigital fingers are designed into sawtooth shape to decrease the influence of centrifugal acceleration. The strain sensor chip is 4mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times4$ </tex-math></inline-formula> mm in size, and is fabricated by a simple SOI process. Connecting the sensitive capacitor with an inductor, an LC resonant tank is formed, and the strain signal can be read out wirelessly and passively through a readout coil. Measurement results show that, in the range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0\sim 1000~\mu \varepsilon $ </tex-math></inline-formula> , the sensitivity of the LC strain sensor reaches 34kHz/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \varepsilon $ </tex-math></inline-formula> , and the gauge factor (GF) of the strain sensor reaches 430. The influence of thickness of adhesive layer on the strain sensitivity is investigated. When the thickness of the adhesive layer reaches <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$500~\mu \text{m}$ </tex-math></inline-formula> , the applied stress cannot be transferred at all. Finally, the LC strain sensor is tested on a rotating platform. The measured resonant frequency shows only 0.4% deviation under 1000m/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> centrifugal acceleration.

Input-series hybrid dual active bridge DC-DC converter combined with LC resonant tank

Input-series hybrid dual active bridge DC-DC converter combined with LC resonant tank

A Wireless Passive Vibration Sensor Based on High‐Temperature Ceramic for Harsh Environment

This paper proposes a wireless passive vibration sensor based on high‐temperature ceramics for vibration measurement in harsh environments such as automotive and advanced engines. The sensor can be equivalent to an acceleration‐sensitive RF LC resonance tank. The structural design of the LC tank and the signal wireless sensing mechanism are introduced in detail. The high‐temperature mechanical properties of the sensitive structure are analyzed using ANSYS at 25–400°C, which proves the usability of the vibration sensor in high‐temperature environment. The three‐dimensional integrated manufacturing of vibration sensors with a beam‐mass structure based on high‐temperature ceramics is completed by a bonding process. Finally, the performance of the sensor is tested on a built experimental platform, and the results show that the vibration sensitivity is approximately 1.303 mv/m·s-2, and the nonlinear error is approximately 4.3%. The vibration sensor can work normally within 250°C, and the sensitivity is 0.989 mv/m·s-2.

Resonant Energy Carrier Base Active Charge-Balancing Algorithm

This paper presents a single LC tank base cell-to-cell active voltage balancing algorithm for Li-ion batteries in electric vehicle (EV) applications. EV batteries face challenges in accomplishing fast balancing and high balancing efficiency with low circuit and control complexity. It addresses that LC resonant tank uses an energy carrier to transfer the voltage from an excessive voltage cell to the lowest voltage cell. The method requires 2N - 4 bidirectional MOSFET switches and a single LC resonant circuit, where N is the number of cells in the battery strings. The balancing speed is improved by allowing a short balancing path for voltage transfer and guarantees a fast balancing speed between any two cells in the battery string, and power consumption is reduced by operating all switches in zero-current switching conditions. The circuit was tested for 4400 mAh Li-ion battery cells under static, cyclic, and dynamic charging/discharging conditions. Two battery cells at the voltage 3.93 V and 3.65 V were balanced after 76 min, and the balancing efficiency is 94.8%. The result of dynamic and cyclic charging/discharging conditions shows that the balancing circuit is applicable for the energy storage devices and Li-ion battery cells for EV.

Bidirectional Resonant CLLC Charger for Wide Battery Voltage Range: Asymmetric Parameters Methodology

The CLLC bidirectional resonant converter has significant potential in battery chargers and dc microgrids, due to its bidirectional power transfer capability. To ensure uniform characteristics for bidirectional operation, secondary LC resonant tank components are usually designed to equal the primary LC components after reflection. This conventional design method is regarded as the symmetric design. It is used in applications where wide voltage regulation is not required, such as CLLC dc transformers. However, for bidirectional battery charger applications, the battery has a wide voltage range variation, and gain requirements during charging and discharging are different. These asymmetric characteristics could lead to undesirable large switching frequency range if a conventional symmetric CLLC design is employed. To address this issue, a detailed asymmetric parameters methodology (APM) is proposed in this article. It can design gain curves for charging and discharging modes separately. This enables overlapping of the switching frequency range for both modes, thereby reducing the bidirectional frequency range variation. It brings lower switching loss caused by excessive high frequency, and relieve the extra conduction loss and current stress of power switches as well. Finally, a detailed analysis of the proposed APM is provided and validated with simulations and experiments.

Low-Profile Omnidirectional WIFI Antennas With Pattern Reconfigurability Inspired by Meta-Resonators

A family of low-profile, omnidirectional antennas inspired by metamaterial resonators (meta-resonators) for WIFI applications is proposed. Two novel meta-resonators with an inductive feeding are presented. They can be considered as an LC resonant tank. Arbitrary size miniaturization could be obtained. Three rotated metamaterial unit cells constitute a ring-shaped structure, which generates a horizontally polarized, omnidirectional radiation. A direct microstrip power divider is used to excite them in-phase, achieving a small and low-profile magnetic dipole-like antenna. Their working principles are illustrated in detail by equivalent circuit and current distribution. Two omnidirectional antennas based on different meta-resonators and one pattern-reconfigurable antenna are fabricated and measured, respectively. Their measured −10 dB frequency bandwidth, peak gain, and radiation efficiency are greater than 2.4–2.48 GHz, 1.17 dBi, and 80%, respectively. They demonstrate superior advantages in terms of a miniaturized/low-profile size, simple structure, good bandwidth, and omnidirectional radiation performance, which are well positioned for 2.40 GHz WIFI router or indoor communications.

Analysis and Comparison of Rad-Hard Ring and LC-Tank Controlled Oscillators in 65 nm for SpaceFibre Applications.

This work presented a comparison between two Voltage Controlled Oscillators (VCOs) designed in 65 nm CMOS technology. The first architecture based on a Ring Oscillator (RO) was designed using three Current Mode Logic (CML) stages connected in a loop, while the second one was based on an LC-tank resonator. This analysis aimed to choose a VCO architecture able to be integrated into a rad-hard Phase Locked Loop. It had to meet the requirements of the SpaceFibre protocol, which supports frequencies up to 6.25 GHz, for space applications. The full custom schematic and layout designs are shown, and Single Event Effect simulations results, performed with a double exponential current pulses generator, are presented in detail for both VCOs. Although the RO-VCO performances in terms of technology scaling and high-integration density were attractive, the simulations on the process variations demonstrated its inability to generate the target frequency in harsh operating conditions. Instead, the LC-VCO highlighted a lower influence through Process-Voltage-Temperature simulations on the oscillation frequency. Both architectures were biased with a supply voltage of 1.2 V. The achieved results for the second architecture analyzed were attractive to address the requirements of the new SpaceFibre aerospace standard.

Single event transient study on PMOS-NMOS cross-coupled LC-VCO using PLL

ABSTRACT A theoretical analysis for single event transient phenomena in a cross-pair LC-VCO (Inductor Capacitor-VCO) is presented. The analytical model developed using unit step approximation for the dual double exponential SET current pulse closely captures the SET phenomenon in the LC resonant tank. Also, a model developed to capture the increase or decrease in the transconductance of the cross pair VCO in response to SET hit in the tail transistor and the transistor connected to the output of the VCO is presented. The developed model helps to capture the voltage and phase variation caused by the SET pulse more accurately in the oscillator. Further, the performance of LC-VCO under SET hit has been observed within PLL for different swing values. The simulation result shows that the recovery time and phase displacement produced by SET can be reduced by biasing the LC-VCO in the current limited regime and by having a large swing. The simulation results for cross-coupled LC-VCO are validated with 90 nm CMOS process technology.

An inline pseudoelliptic self‐packaging substrate integrated suspended line filter with mixed electric and magnetic coupling

A novel compact and self-packaging inline pseudoelliptic filter is proposed. The proposed filter exploits controllable mixed electric and magnetic coupling using substrate integrated suspended line (SISL) technology. Based on a synchronously tuned coupled resonator circuit with parallel LC resonant tank and admittance inverters, general formulas for extracting electric and magnetic coupling coefficients are derived. Meanwhile, a basic mixed coupled SISL resonator pair is investigated and a systematic design procedure of a second-order mixed coupled SISL filter is also given. Two prototypes of the second-order filter with one transmission zero (TZ) at either upper or lower stopband are designed, which is corresponding to either magnetic or electric coupling dominant case. Furthermore, for asynchronously tuned coupled resonator cases, an inline third-order pseudoelliptic SISL filter characterized by symmetric TZs is designed, fabricated, and measured for validation. The simulated and measured results show a good agreement with the synthesized ones.