scholarly journals Resonant frequency stabilization technique in series-series contactless energy transfer systems

2017 ◽  
Vol 66 (3) ◽  
pp. 547-558 ◽  
Author(s):  
M. Marcinek ◽  
M. Hołub ◽  
S. Kalisiak ◽  
R. Pałka
Keyword(s):  
Energy Transfer ◽  
Phase Shift ◽  
Resonant Frequency ◽  
Resonance Frequency ◽  
Frequency Stabilization ◽  
Resonant Circuit ◽  
Power Circuit ◽  
In Series ◽  
Stabilization Technique ◽  
Zero Phase

AbstractA technique for stabilization of resonant frequency is proposed in this paper. An additional power circuit, a compensator that allows keeping constant resonance frequency was introduced by the authors. In the presented solution the resonant circuit frequency stabilization is achieved by forcing a zero phase shift between the current and the voltage of the main switching module.

scholarly journals Study on the Main Factors of Frequency Variation of LC Resonant Prestress Detection Method

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Benniu Zhang ◽  
Yuanyuan Zhao ◽  
Xingxing Li ◽  
Yanpeng Su ◽  
Qiang Yin ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Resonance Frequency ◽  
Relative Permeability ◽  
Stress Measurement ◽  
Length Change ◽  
Resonant Circuit ◽  
Frequency Variation ◽  
Stress Detection ◽  
Electric Circuits ◽  
Stress Changes

Stress loss of prestressed steel strands of existing bridges influences their bearing capacity, so it is of great significance to realize the stress detection. A steel strand that has an inductive property is designed into the resonant circuit, which can realize the stress measurement of the steel strands by testing the resonant frequency. This method is a promising approach for the stress detection of the steel strands. Previous research found that structural stress made the permeability of steel strands change due to the influence of magnetoelastic effect. In the process, the length of steel strands is also changed. Therefore, further research needs to be done to verify the main influence parameter affecting the resonant frequency of the circuit. Furthermore, it is very important to know how the stress affects the resonant frequency to realize the detection of the prestressed force of the steel strands. Therefore, in this paper, the relationship between stress and relative permeability and length is analyzed theoretically, and the theory of stress frequency of steel strands is modified and verified by experiments. The stress-frequency experiments of steel strands and aluminum strands with great difference in relative permeability are carried out. Experiments on stress frequencies of 7-Ф15.20 mm steel strands with different lengths are carried out. The influence of length and permeability parameters on resonance frequency is analyzed. The experimental results show that under the same conditions, the resonant frequencies of steel strands and aluminum strands are almost the same on LC electric circuits, and the resonant frequency decreases linearly with the increase of the natural length of the component and increases linearly with the increase of stress. Consequently, compared with the influence of length change on LC electromagnetic resonance frequency, the relative permeability of the stress change component can be ignored. The stress changes the resonant frequency mainly by changing the length of the strands.

scholarly journals Capacitor Commutation Method for MVDC Hybrid Circuit Breakers

Designs ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 28
Author(s):  
Hyosung Kim
Keyword(s):  
Short Circuit ◽  
Circuit Breaker ◽  
Reverse Current ◽  
Resonant Circuit ◽  
Power Circuit ◽  
Power Sources ◽  
Semiconductor Switch ◽  
Current Commutation ◽  
Dc Circuit Breaker ◽  
Hybrid Circuit

The medium voltage DC (MVDC) type system can connect multiple terminals to a common MVDC bus, so it is possible to connect several renewable DC power sources to the common MVDC bus, but a DC circuit breaker is needed to isolate short circuit accidents that may occur in the MVDC bus. For this purpose, the concept of a hybrid DC circuit breaker that takes advantage of a low conduction loss contact type switch and an arcless-breaking semiconductor switch has been proposed. During break the hybrid switch, a dedicated current commutation device is required to temporarily bypass the load current flowing through the main switch into a semiconductor switch branch. Existing current commutation methods include a proactive method and a reverse current injection method by a LC (Inductor-capacitor) resonant circuit. This paper proposes a power circuit of a new MVDC hybrid circuit breaker using a low withstanding voltage capacitor branch for commutation and a sequence controller according to it, and verifies its operation through an experiment.

scholarly journals Design and Analysis of a Novel Piezoceramic Stack-based Smart Aggregate

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6438
Author(s):  
Guangtao Lu ◽  
Xin Zhu ◽  
Tao Wang ◽  
Zhiqiang Hao ◽  
Bohai Tan
Keyword(s):  
Resonance Frequency ◽  
Electromechanical Coupling ◽  
Structural Parameters ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Stress Waves ◽  
Parallel Connection ◽  
Smart Aggregate ◽  
In Series ◽  
Piezoelectric Wafers

A novel piezoceramic stack-based smart aggregate (PiSSA) with piezoceramic wafers in series or parallel connection is developed to increase the efficiency and output performance over the conventional smart aggregate with only one piezoelectric patch. Due to the improvement, PiSSA is suitable for situations where the stress waves easily attenuate. In PiSSA, the piezoelectric wafers are electrically connected in series or parallel, and three types of piezoelectric wafers with different electrode patterns are designed for easy connection. Based on the theory of piezo-elasticity, a simplified one-dimensional model is derived to study the electromechanical, transmitting and sensing performance of PiSSAs with the wafers in series and parallel connection, and the model was verified by experiments. The theoretical results reveal that the first resonance frequency of PiSSAs in series and parallel decreases as the number or thickness of the PZT wafers increases, and the first electromechanical coupling factor increases firstly and then decrease gradually as the number or thickness increases. The results also show that both the first resonance frequency and the first electromechanical coupling factor of PiSSA in series and parallel change no more than 0.87% as the Young’s modulus of the epoxy increases from 0.5 to 1.5 times 3.2 GPa, which is helpful for the fabrication of PiSSAs. In addition, the displacement output of PiSSAs in parallel is about 2.18–22.49 times that in series at 1–50 kHz, while the voltage output of PiSSAs in parallel is much less than that in parallel, which indicates that PiSSA in parallel is much more suitable for working as an actuator to excite stress waves and PiSSA in series is suitable for working as a sensor to detect the waves. All the results demonstrate that the connecting type, number and thickness of the PZT wafers should be carefully selected to increase the efficiency and output of PiSSA actuators and sensors. This study contributes to providing a method to investigate the characteristics and optimize the structural parameters of the proposed PiSSAs.

Performance Analysis of Different Modulation Formats in Optical Communication

2016 ◽  
Vol 37 (2) ◽  
Author(s):  
Kulwinder Singh ◽  
Maninder Singh ◽  
Kamaljit Singh Bhatia ◽  
Hardeep Singh Ryait
Keyword(s):  
Performance Analysis ◽  
Phase Shift ◽  
Resonant Frequency ◽  
Optical Communication ◽  
Data Transmission ◽  
Modulation Formats ◽  
Differential Phase Shift ◽  
Eye Diagram ◽  
The Difference ◽  
Sequence Generator

AbstractIn this paper, we demonstrated the variation of different parameters with quadrature amplitude modulation (QAM) and differential phase shift key (DPSK) sequence generator, which generates modulated signals, in data transmission for communication and analysed that how the difference of these sequence generators effect its resonant frequency (RF) value, eye diagram and electrical constellation representation of the system.

scholarly journals Design Optimization of MEMS Based LLC Tunable Resonant Converter for Power Supplies on Chip

2013 ◽  
Vol 705 ◽  
pp. 258-263
Author(s):  
Fahimullah Khan ◽  
Yong Zhu ◽  
Jun Wei Lu ◽  
Dzung Dao
Keyword(s):  
Resonant Frequency ◽  
Resonance Frequency ◽  
Parallel Plate ◽  
Power Supplies ◽  
Resonant Converter ◽  
Load Variations ◽  
Leakage Inductance ◽  
Variable Capacitor ◽  
Numerical Software ◽  
On Chip

In this paper, a novel MEMS based LLC converter is proposed for on chip power supplies. The design is optimized based on commercially available Metal MUMPs process for fabrication. The resonant frequency is optimized at 20MHz and MEMS based variable capacitor is fabricated on the chip to tune the peak resonance frequency of circuit which varies due to the load variations. The Design is simulated in FEM based numerical software COMSOL and Intellisuite. According to analysis the magnetizing inductance of 42nH and leakage inductance of 40nH has been achieved from 16 mm2 rectangular coil transformer. The total capacitance of 1500pF has been achieved from parallel plate capacitors and variation of 3pF has been achieved from variable capacitor.

Micromachined Snap-In Resonators

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 001920-001935 ◽  
Author(s):  
Colin Stevens ◽  
Robert Dean ◽  
Chris Wilson
Keyword(s):  
Resonant Frequency ◽  
Proof Mass ◽  
Pressure Sensors ◽  
Mass System ◽  
Dc Voltage ◽  
Movable Electrode ◽  
Mems Resonators ◽  
Spring Force ◽  
In Series ◽  
Fixed Electrode

MEMS resonators have many applications, including micromachined gyroscopes, resonating pressure sensors and RF devices. Typically, MEMS resonators consist of a proof mass and suspension system that allows the proof mass motion in one or two directions. Micromachined actuators provide kinetic energy to the proof mass, usually at its resonant frequency. In the simplest resonators, the actuators are driven with an AC signal at or near the resonant frequency. In more complex resonators, the actuator-proof mass system is placed in an amplifier feedback circuit so that the electromechanical system self-resonates. MEMS parallel plate actuators (PPAs) are simple to realize, yet complex nonlinear variable capacitors. If a DC voltage is applied in attempt to move the proof mass greater than 1/3 of the electrode rest gap distance, the device becomes unstable and the electrodes snap into contact. A current limiting resistor is often placed in series with the PPA to limit short circuit current due to a snap-in event. Consider the effect of placing a large resistor, on the order on 10 meg-Ohms, in series with the PPA. Then apply a DC voltage across the resistor-PPA pair of sufficient voltage to cause snap-in. Once the electrostatic force (ES) exceeds the spring force (SF), the electrodes will accelerate toward each other. The capacitance between the electrodes swells as the separation distance shrinks. Since the large resistor limits the charging rate of the capacitor, the voltage across it drops. Once the SF exceeds the EF, the momentum of the movable electrode brings it into contact with the fixed electrode, discharging the capacitor. The movable electrode then accelerates away from the fixed electrode while the resistor slowly allows recharging. After recharging, the cycle repeats resulting in stable oscillation. This resonator requires only a DC power supply, a resistor and a MEMS PPA.

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