Resonant Bridge Research Articles

A Hybrid Modular DC Solid-State Transformer Combining High Efficiency and Control Flexibility

This article presents a hybrid modular dc solid-state transformer (HMDCSST) composed of a series resonant dual active bridge (SR-DAB) and a phase-shift dual active bridge (PS-DAB), aiming at improving the transfer efficiency as well as maintaining the control flexibility key problems in terms of modeling and control strategy are discussed in this article. The generalized average and small-signal models of the HMDCSST are derived and confirmed by simulation, in which two LC filters are also considered to reduce the ripple components of the input and output currents. Based on the models, the control strategies to achieve the flexible control of the output voltage and power are designed. Moreover, as a key problem for HMDCSST, the design principle of the number for each type of DAB is discussed to meet the demands of the grid. Finally, a three-module prototype of HMDCSST consisting of one PS-DAB and two SR-DAB modules was built-up and tested, and the results proved that HMDCSST has higher efficiency than the traditional DCSST based on PS-DABs purely, without sacrificing the output voltage and power regulating capability in the meanwhile.

A Triaxial Accelerometer Based on Differential Resonant Beams and Force-Balanced Capacitive Plates

This paper presents the design, simulation, fabrication, and experiment of a triaxial accelerometer based on differential resonant beams and force-balanced capacitive plates. The triaxial accelerometer is composed of a proof mass, four bridge resonators with both end clamped and operating in flexure vibration mode, four L-type supporting beams, and a top plate and a bottom plate. The in-plane acceleration is measured by bridge resonators. The gravity center of the proof mass and the neutral layer of L-type supporting beams are located within the same plane to minimize the rotation of the proof mass subjected to in-plane acceleration. The cross-axis sensitivities of X-axis and Y-axis resonant beams under lateral in-plane acceleration are 1.97% and 1.71%, respectively. A force-balanced differential plate capacitor composed of a proof mass, a top plate, and a bottom plate is used to detect acceleration along Z-axis. The small displacement of the proof mass in the normal direction of the chip reduces the cross-axis sensitivity of the bridge resonators subjected to acceleration along Z-axis. The complementation of the resonance detection mechanism and the force balance capacitance mode makes the triaxial accelerometer exhibit low cross-axis sensitivity. The simulated and experimental results prove this conclusion.

Analysis, modelling and implementation of multi-phase single-leg DC/DC converter for fuel cell hybrid electric vehicles

ABSTRACT Multi-phase converter topologies for use in high-power density applications such as fuel cell hybrid electric vehicles (FCHEVs) have received huge interest in recent years. In this paper, a multi-phase interleaved structure and its control has been proposed for use with a PEMFCHEV to decrease the current ripples of the interleaved inductors, the output voltage ripples of the bus capacitor, and the size and weight of their passive components with higher efficiency compared with the conventional boost converter (CBC) and two-phase interleaved boost converter (TPIBC). Furthermore, the fuel cell stack and the lithium-ion (Li-ion) battery are connected to the same DC voltage bus through a multi-phase single-leg (MPSL) converter and a resonant dual active bridge isolated bidirectional DC/DC converter (RDAB-IBDC), respectively. The proposed DC/DC converter topology and its controller is designed and investigated by using PSCAD (4.6.0) simulator. The proposed DC/DC converter is experimentally validated with results obtained from a prototype set-up that has been built and tested in the laboratory based on dSPACE (RTI1104). Finally, the simulation and experimental results have shown that the proposed converter is more effective than other DC/DC converter topologies and achieves higher performance and reliability for high-power density DC/DC converters.

LLC Resonant Converter for LEV (Light Electric Vehicle) Fast Chargers

This paper presents a Light Electric Vehicle (LEV) fast charger with a Lithium-Ion Battery (LIB) and Super-Capacitor (SC). The LEV fast charger consists of an AC/DC rectifier and LLC (Inductor-Inductor-Capacitor) resonant Full bridge converter. The LLC resonant converter has high-efficiency and low switching loss because of Zero Voltage Switching (ZVS). So, it is used widely in the industry. In general, the fast charger algorithm uses the Constant Current (CC) mode and Constant Voltage (CV). The CC mode starts at first and then the CV mode finishes. However, there is a big control value gap between the CC mode and CV mode. Therefore, when changing from CC to CV, the transient state occurs. To compensate for the transient state, we propose a new control algorithm. By means of this algorithm, we can achieve a higher level of safety and stability. The fast charger with LIB of 800 Wh and SC of 50 Wh is analyzed and verified, and we obtain a maximum efficiency of 96.4%. The discussions are validated using the LLC resonant full bridge converter prototype at the laboratory level.

Full Bridge Resonant Inverter for Blade Induction Heating Application

This paper presents blade induction heating application using full bridge resonant inverter including six parts: step-down transformer, full wave bridge rectifier, Pulse Width Modulation PWM signal, full-bridge Inverter by using power MOSFETs, high frequency transformer, and workpiece. The workpiece is 2.5-cm width and 15-cm length with 6-turns coil. The result shows that the blade is heated for 60 seconds with the temperature not less than 657.2 ºC. The output power of heating is generated appropriately 1.10 kW, at full load.

Wheel-rail impact interaction on the high-speed railroad bridges

The paper describes interaction of high-speed rolling stock and railroad bridge deck and proves the importance of adequate model of wheel (mechanism) and rail (structure) interaction. The model must consist of a rail and slabs of the ballastless deck. The paper characterizes the results of computer simulation of perspective rolling stock passing through high speed railroad bridge, that contains the uniform bridge superstructure for Moscow – Kazan line. The paper shows that in case of resonant bridge superstructure vibration the risk of derailment is high because of the decline of the wheel-rail contact force down to zero, which means wheel uplift. Moreover, the impact of the wheel is the result of uplift and the impact value is similar to the impact from impossible damages of wheels or rail on high speed railroad in consequence of which rail breaking occur. This rail breaking is the most frequent reason of derailment. The impact forces are equivalent to the impact of the fresh flat of the wheel and may be more than 300 kN while static force is equal to 85 kN. The vertical contact force is rising from zero to maximum value for 0.002 to 0.004 s after uplift. The computer simulation results show that it is the bridge superstructure resonance, which leads to impact interaction. The rail fasteners rigidity decline causes vertical interaction force decrease during the impact but the derailment risk still exists during vibration of “bridge – track – train” system.

The Regulation Characteristics of Bridge Modular Switched-Capacitor Ac-Ac Converter

The switched-capacitor (SC) converter has become a hot candidate to replace power electronics transformer (PET) in commercial and residential applications, especially in micro-grids. However, its poor regulation blocks it wide application. This paper presents an improved phase-shift control strategy for a resonant bridge modular switched-capacitor (RBMSC) ac-ac converter. On the basis of maintaining existing merits of the reported BMSC-based ac-ac converter, its output voltage can be adjusted continuously with a relatively wide margin, breaking through inherent difficulty in step-less regulation. Meanwhile, the bidirectional operation, including step-down and step-up modes, could be realized conveniently by changing the of range phase-shift angle. In addition, the partial switches are turned on under zero voltage switching (ZVS) and all switches realize ZVS turn-off, resulting in reduction of switching loss. Due to one switch in each bidirectional switch always works under synchronous rectification state instead of diode conduction, conduction loss will be reduced compared with other SC ac-ac converters. Most importantly, the safe-commutation issue in the introduced resonant branch is well solved and the voltage spike across switches is alleviated significantly. Finally, the experimental results are provided to demonstrate the validity of the theoretical principle of the converter.

Design and analysis of a full bridge LLC DC-DC converter for auxiliary power supplies in traction

This paper focuses on an 8 kW LLC resonant full bridge DC-DC converter topology using a high frequency transformer for auxiliary power supply systems in traction. The full bridge DC-DC converter with the LLC resonant network has been tested under hard switching and zero current switching conditions with 100 kHz switching frequency. In addition to this, an observation made for the effect of dead time variation of the power switches to improve the overall system efficiency. This paper describes the efficiency of the ZCS full bridge converter by considering different input power levels and also compared with hard switched topology. This paper presents the operating principles, simulation analysis, and experimental verification for 3 kW to 8 kW LLC resonant full bridge converter with 1200 V/40 A IGBTs, and its efficiency comparison.

Effect of soil properties on the dynamic response of simply-supported bridges under railway traffic through coupled boundary element-finite element analyses

Railway induced vibrations on short-to-medium span simply-supported (SS) bridges is addressed in this contribution. Such structures may experience high levels of vertical acceleration at the platform, leading to adverse consequences such as a premature degradation of the ballast layer and passenger discomfort. In the present study, the evolution of the bridge dynamic response when soil-structure interaction (SSI) is taken into account is investigated. To this end a coupled three-dimensional (3D) Boundary Element-Finite Element model (BEM-FEM) formulated in the time domain is implemented to reproduce the soil and structural behaviour, respectively. First, a set of soil-bridge systems of interest is defined, covering a wide range of lengths and natural frequencies for the structures, and an interval of expectable elastic properties and damping levels for the soil. Then, different types of analyses are performed on the soil-bridge systems extracting conclusions regarding the effect of including SSI in numerical models for predicting the bridge behaviour under railway traffic. In particular natural frequencies and modal damping levels are identified, and the structure amplification after the passage of a moving load in free vibration is investigated. Conclusions regarding how resonance and cancellation conditions may be affected by soil properties are extracted. Finally, the dynamic response of a real bridge, belonging to the Spanish railway network, is evaluated under the circulation of trains that induce second and third resonances of the bridge fundamental mode. The effect of the soil flexibility, soil material damping and the bridge resonance order are evaluated. Conclusions regarding the appropriateness of the results provided by common models which do not include SSI effects are extracted.

A Fixed-Frequency ZVS Integrated Boost Dual Three-Phase Bridge DC–DC LCL-Type Series Resonant Converter

A new fixed-frequency controlled three-phase dc–dc LCL-type series resonant converter with integrated boost function is proposed for medium to large power applications with wide input voltage variation that is typical of alternate energy sources. The converter includes a dual three-phase LCL-type resonant bridge inverter modules connected in parallel, thus significantly reducing the component stresses when subjected to medium to large power applications. The fixed-frequency control of the output power is achieved by phase shifting the gating signals of one module with respect to the other, while the rectified voltage at the secondary windings of a three-phase high-frequency transformer connected between the two modules is added to the input voltage to boost the supply voltage to the modules. The zero-voltage-switching of all the switches is accomplished by designing the converter to operate in the lagging PF mode for wide variations in the input voltage and the load. Detailed modeling of the three-phase boost section is done and the steady-state analysis of the proposed converter for three-phase LCL-type dc–dc converter modules using complex ac circuit analysis method is presented. For illustration purpose, a dc–dc converter of 600 W is designed, and its performance is verified using PSIM simulations. An experimental model of the converter is built in the laboratory to verify its performance for wide variations in input voltage and load changes.

MEMS Magnetic Sensor with Bridge‐Type Resonator and Magnetostrictive Thin Film

SUMMARYThis paper reports on fabrication and characterization of resonant‐type mechanical MEMS magnetic sensors using magnetostrictive FePd sputtered film. The sensor has a thin Si resonator bridge with a PZT piezoelectric thin film element for excitation. The resonator is pulled by other bridges with the FePd film when magnetic flux is applied. The sensor was fabricated from an SOI wafer by sol‐gel PZT deposition, FePd sputtering, and Si etching processes. The completed sensor showed a resonant peak with a Q factor of 229 at 26.39 kHz. When magnetic flux was applied along the microbridges, resonant frequency drastically decreased due to relaxation of initial deflection of the resonant bridge. Magnetic flux can be detected by resonant frequency change with a sensing resolution of 0.2 G per 0.1 Hz. When excitation frequency was fixed at slightly below the resonant frequency, amplitude of the bridge vibration slightly decreased with increasing magnetic flux in low magnetic flux region. High sensitive sensing of magnetic flux was difficult by the amplitude change. It was found that the magnetic sensor showed large thermal drift.

A scalable pressure sensor based on an electrothermally and electrostatically operated resonator

We present a pressure sensor based on the convective cooling of the air surrounding an electrothermally heated resonant bridge. Unlike conventional pressure sensors that rely on diaphragm deformation in response to pressure, the sensor does not require diaphragms of the large surface area, and hence is scalable and can be realized even at the nanoscale. The concept is demonstrated using both straight and arch microbeam resonators driven and sensed electrostatically. The change in the surrounding pressure is shown to be accurately tracked by monitoring the change in the resonance frequency of the structure. The sensitivity of the sensor, which is controllable by the applied electrothermal load, is shown near 57 811 ppm/mbar for a pressure range from 1 to 10 Torr. We show that a straight beam operated near the buckling threshold leads to the maximum sensitivity of the device. The experimental data and simulation results, based on a multi-physics finite element model, demonstrate the feasibility and simplicity of the pressure sensor.

Study of the Phase Shift Plus PWM Control Strategy Based on a Resonant Bridge Modular Switched-Capacitor Converter

Bridge modular switched-capacitor converter (BMSCC) has been reported with symmetric and modular structure, and featured less output voltage ripple, less components cost, and convenient voltage extension but weak output voltage regulation. This paper presents a phase shift plus pulse width modulation (PWM) control strategy for the novel resonant BMSCC. With this control method, output voltage regulation and the limitation of the loop peak current to a proper range are implemented. Also, output voltage ripple could be effectively controlled as well through the voltage ripple characteristics analysis in different cases. Detailed analyses of the relationships between the switching phases of MOSFETs and the output voltage, the switching-phases of MOSFETs and the loop peak current are performed. Meanwhile, through optimal switching sequence, the proposed control method ensures that almost all switching devices maintain zero current switching or zero voltage switching operation, which results in high system efficiency. Using simulation software of the saber and hardware platform, the soft switching, output voltage, and peak current characteristics are verified.

Novel Hybrid LLC Resonant and DAB Linear DC–DC Converter: Average Model and Experimental Verification

A novel hybrid LLC resonant and dual active bridge (DAB) linear dc–dc converter is proposed as bus converter, which can achieve soft switching and constant output voltage gain at both the open-loop light load and closed-loop heavy load conditions. This paper focuses on its continuous-time average modeling in detail based on the dc output voltage, the first order terms of two transformer currents and the resonant capacitor voltage, which results in a seven-order model. Additionally, the total control-to-output transfer function is derived for the proposed hybrid converter dynamic analysis. The experimental results have verified that the proposed model can correctly match the small-signal frequency response, and compare with DAB, the related analysis based on the proposed model shows the novel hybrid converter can have a better output voltage response.

Full Bridge Resonant Inverter Using Asymmetrical Control with Resonant-frequency Tracking for Ultrasonic Cleaning Applications

Full Bridge Resonant Inverter Using Asymmetrical Control with Resonant-frequency Tracking for Ultrasonic Cleaning Applications

Investigating the wetting behavior of a surface with periodic reentrant structures using integrated microresonators

The apparent contact angle is frequently used as an indicator of the wetting state of a surface in contact with a liquid. However, the apparent contact angle is subject to hysteresis that depends furthermore strongly on both the material properties and the roughness and structure of the sample surface. In this work, we show that integrated microresonators can be exploited to determine the wetting state by measuring both the frequency shift caused by the hydrodynamic mass of the liquid and the change in the quality factor as a result of damping. For this, we integrated electrically driven hybrid bridge resonators (HBRs) into a periodically structured surface intended for wetting experiments. We could clearly differentiate between the Wenzel state and the Cassie-Baxter state because the resonant frequency and quality factor of the HBR changed by over 35% and 40%, respectively. This offers the capability to unambiguously distinguish between the different wetting states.

Tuning Performance of Silicon Carbide Micro-Resonators

Silicon carbide microresonators have been designed, fabricated and tested. Three designs have been studied: cantilever, bridge and ring resonators. The devices have been actuated electrothermally and sensed piezoelectrically. The resonant frequency as well as the amount of frequency shift as a function of DC bias voltage for the three designs have been characterized electrically using two-port measurements. It has been found that the DC tuning sensitivities of the ring and bridge resonators (between 58,000 ppm/V and 62,000 ppm/V) are significantly higher than for the cantilever (240 ppm/V). Simulations have shown that a larger temperature change, hence a larger compressive stress induced in the SiC layer exists in the bridge design compared to the cantilever design as the DC bias voltage is increased. The higher DC tuning sensitivity for the bridge design could be a result of the combination of the location of the electrode thus causing higher thermally induced compressive stress as well as the clamped-clamped beam configuration.

A High Power Medium Voltage Resonant Dual Active Bridge for MVDC Ship Power Networks

This paper presents the design and control of a megawatt scale, medium voltage, medium frequency resonant dual active bridge dc-dc converter operating as a bus-tie converter in a dc distribution network. The high voltage (HV) side of the converter is designed using series connected low voltage (LV) devices to efficiently operate at higher switching frequencies. A combined variable frequency and phase-shift control method is proposed to achieve input-output power flow and voltage control, while maintaining soft switching operation for both the HV and LV bridges. Two 1 MW converter prototypes operated in a back-to-back arrangement are presented to validate the proposed topology and control.

Mass and position determination of an accreted particle from the vibration of a beam-based nanomechanical resonator

We present a generalized theoretical analysis of the vibration of a micro/nano bridge resonator with a particle at an arbitrary location by considering the combined effect of the beam stiffness and string tension in the resonator. By combining resonant frequencies of at most three consecutive symmetric vibration modes, the developed model can unambiguously resolve the particle mass and position. The methodology is verified using published results. The finding is further validated numerically by finite element modeling using a microbridge with and without an added particle, which proves that the method resolves the particle mass and position with high accuracy.

ブリッジ構造の共振子と磁歪膜をもつMEMS磁気センサ

This paper reports on fabrication and characterization of resonant-type mechanical MEMS magnetic sensors using magnetostrictive FePd sputtered film. The sensor has a thin Si resonator bridge with a PZT piezoelectric thin film element for excitation. The resonator is pulled by other bridges with the FePd film when magnetic flux is applied. The sensor was fabricated from an SOI wafer by sol-gel PZT deposition, FePd sputtering, and Si etching processes. The completed sensor showed a resonant peak with a Q factor of 229 at 26.39 kHz. When magnetic flux was applied along the micro-bridges, resonant frequency drastically decreased due to relaxation of initial deflection of the resonant bridge. Magnetic flux can be detected by resonant frequency change with a sensing resolution of 0.2 Gauss per 0.1 Hz. When excitation frequency was fixed at slightly below the resonant frequency, amplitude of the bridge vibration slightly decreased with increasing magnetic flux in low magnetic flux region. High sensitive sensing of magnetic flux was difficult by the amplitude change. It was found that the magnetic sensor showed large thermal drift.