Resonant Voltage Research Articles

ФЕРРОРЕЗОНАНСНЫЕ ПЕРЕНАПРЯЖЕНИЯ В ЭЛЕКТРОУСТАНОВКАХ 6–220 кВ: ТЕОРИЯ И РЕЗУЛЬТАТЫ ЭКСПЕРИМЕНТАЛЬНЫХ ИССЛЕДОВАНИЙ

Relevance The article is devoted to the systematization and generalization of theoretical and experimental studies of ferroresonance overvoltages in electrical installations 6–220 kV. The need to study this issue is associated with the active introduction of distributed generation facilities into distribution networks, as well as medium and low voltage networks. In power districts with distributed generation facilities, the settings and operation algorithm of relay protection and automation devices differ from the traditional ones used in centralized power supply. The generation parameters and the nature of electromechanical transients also differ, which is caused by the low dynamic stability of generating plants based on synchronous generation and the use of network inverters with energy storage in electronic generation. Thus, due to significant differences in the parameters of the network operation mode with and without distributed generation objects, it is necessary to revise many well-known technical problems, including the issue of ferroresonant processes. Electrical installations of 6–220 kV were chosen as the object of research, since the concept of distributed generation does not imply backbone networks, and the maximum installed power of an individual facility is limited by 25 MW. Aim of Research Aim of research is to systematize and summarize the theoretical and experimental studies of ferroresonance overvoltages in electrical installations 6–220 kV. Research methods To study the circuit-mode conditions for the occurrence of ferroresonant processes in electrical installations of 6–220 kV, an analysis of foreign and domestic publications, standards was carried out, and the theoretical foundations of electrical engineering and the theory of nonlinear electrical circuits were used. Results The physical essence of the phenomenon of ferroresonance, the conditions for the occurrence of ferroresonant processes and measures to prevent them in medium and high voltage networks, experimental studies of ferroresonant processes are considered. The ferroresonant process consists in compensating the inductive and capacitive resistances in the oscillatory circuit with a saturated inductance core. There are various modes of ferroresonance, which are determined by the initial conditions: fundamental, subharmonic, aperiodic and chaotic. A prerequisite for the occurrence of a ferroresonant process is the power of the power source sufficient to saturate the inductance core. Non-linear inductance that can participate in the formation of an oscillatory circuit are voltage transformers, power transformers, shunt reactors. The capacity of the circuit can be a power line, a busbar system, a capacitor bank, shunt capacitors of switches. Hardware and operational measures to protect against ferroresonant processes in electrical installations are aimed at changing the capacitance or inductance of network elements that may participate in the formation of a ferroresonant oscillatory circuit, preventing the formation of such a circuit or reducing its quality factor. The results of experimental studies of ferroresonant processes do not contradict the guidelines for protection against resonant voltage increases in electrical installations. Keywords: ferroresonance overvoltages, distributed generation, ferroresonant process, electrical installation, busbar system, high-voltage switch, non-linear inductance

Проектирование системы фазовой автоподстройки частоты

The article is devoted to the development of a phase locked loop (PLL) system using the CD4046 integrated circuit. To achieve this goal, the principles of operation of two types of phase detectors were investigated. In the second half of the article, the main transfer functions of the PLL system are derived, an example of calculating the feedback controller is considered. The reliability of the calculation results is confirmed by modeling a computer model of a resonant voltage inverter.

Design and Control of Modified Resonant Voltage Multiplier Rectifier for Photovoltaic Applications Using Electrolytic Capacitive Material

In this paper, a modified resonant voltage multiplier rectifier (RVMR) has been developed to improve the voltage gain and efficiency of the proposed converter on PV interconnected renewable energy systems. To acquire the most energy from the PV source, the improved RVMR scheme uses an altered Perturb and Observe (P&O)‐based MPPT approach. This paper develops a modified variable step size P&O MPPT algorithm that can increase the PV system’s dynamic and steady‐state performance at the same time. The recommended variable step size technique addresses the constraints of traditional P&O MPPT. The suggested study uses the MATLAB/Simulink environment to analyze and evaluate voltage gain and efficiency.

철도 차량용 배터리 충전을 위한 LLC 공진형 컨버터의 SiC FET와 Si FET의 병렬 연결에 관한 연구

Wide-Band-Gap (WBG) switching semiconductor has been improved for higher efficiency and higher power density. Especially, SiC FET is the most attractive switching semiconductor for mid-voltage and high power applications, such as, railway transportation. Its desired features for high power converter are low on-state resistance, thermal stability, no reverse recovery, high switching speed, and so on. However, faster switching speed derives higher dv/dt of drain-source voltage, then this result in larger voltage ringing and worse switching noise. In this paper, parallel configuration of SiC FET and Si FET is proposed to suppress voltage ringing and minimize switching noise. Based on the characteristics of output capacitances of both SiC and Si FETs, the switching performances of single SiC FET and parallel connection of SiC/Si FETs are compared of voltage ringing and switching noise in LLC resonant converter for 10kW battery charging module of railway transportation.

A Smart Gate Driver IC for GaN Power HEMTs With Dynamic Ringing Suppression

Conventional di/dt and dv/dt control and gate protection techniques for gallium nitride (GaN) power transistors usually employ external controllers, isolation circuits, discrete pull-up, and pull-down resistors. With large number of components, power modules become more complex and may introduce additional parasitic. Gate driver ICs with segmented output stages and dynamic gate driving have been reported previously to be effective in simultaneously suppressing gate ringing and overshoot voltage while maintaining fast switching speed. However, the programming for dynamic gate driving is rather complicated, requiring the user to load a sequence of driving patterns obtained from trial and error ahead of time. This article presents a gate driver IC for E-mode GaN power transistors with seven segmented output stages. More importantly, it offers a simplified programming method for the dynamic gate driving pattern. The optimal gate drive pattern can be defined by simply adjusting one external bias resistor. The proposed method eliminates the complex trial and error digital control, and can potentially promoting the wider acceptance of dynamic gate driving by the industry. The timing resolution for the gate drive pattern can be varied in steps from 0.5 to 5 ns. It can also be used to drive many commercially available GaN power transistors.

Experimental evaluation of some current injection-voltage reading patterns in electrical impedance tomography (EIT) and comparison to simulation results - Case study: Large scales

Each electrical impedance tomography system to be prosper, usually would had its own current injection and voltage reading patterns within domains under test. So in different domains, each of sensing patterns have different performances. In industrial application for conductive carrier-phases and in large domains, impedance imaging of real phantoms would be advisable candidate for better performance. Therefore in this study, performance of five sensing patterns in a large scale (outer diameter of 700 mm) were evaluated. Based on the sensing patterns, parameters such as; applicability in the domain and online mode, voltage signal-to-noise ratio (SNR), boundary voltage changes (BVC), sensitivity distributions, size error (SE) and ringing, in different object locations were studied by simulation and experimentally. The results illustrated that there is a significant difference between the reconstruction images of simulation and experimental data in the patterns with low SNR. Also, in a pattern with high SNR, due to the low BVC, the desired performance was not achieved. The highest correlation in the image reconstruction of the simulation and experimental data was obtained in the Opposite-Adjacent pattern with high SNR and BVC. The results show that the selection of this sensing pattern can improve the object's SE up to 0.68%.

An Autonomous Vibration-Sensing System for Power Transmission Lines Monitoring

An autonomous vibration-sensing system including of ring magnetoelectric energy scavenger, an energy management module, a plurality of wireless acceleration sensor nodes and APP mobile terminal for power transmission lines monitoring was presented. The ring-type ferrite/piezoelectric composite with strong magnetoelectric couplings and a coil wound around it is used to scavenge the electromagnetic energy around the conductor, and the energy management module successively fulfill the functions of inductive/capacitive resonance matching, rectification and voltage stabilization and storage/release of the scavenged electric energy, and then provides driving power for signal acquisition and data transmission of 4G wireless acceleration sensor nodes. Testing results show that the collected energy can fulfill the power-supplying requirements of ADXL345, and the real-time as well as historical data curves within a specified time can be acquired through 4G and narrowband internet of things technologies.

Analysis and Design of an Output Adjustable Resonant Switched Capacitor Converter

This article proposes an output adjustable resonant switched capacitor converter (OARSCC) based on resonant voltage doubler. The proposed OARSCC works in regulated mode with on time fixed frequency modulation. The output is regulated through controlling the power stored in resonant capacitor. With proper converter configuration, the conversion ratio is approximate to a straight line. When OARSCC works in nonregulated mode, the efficiency is higher, but the ratio is fixed. The loads of different stage are derived with load equivalent method to build an accurate model of the topology. The load equivalent method is also applicable to other types of multistage switched capacitor converter (SCC), such as Fibonacci SCC. A 100-W converter with a maximum boost ratio of eight times is made to verify the proposed topology and load equivalent method.

Resonance enhanced magnetoelastic method with high sensitivity for steel stress measurement

To increase the test sensitivity, the resonance theory was introduced to the magnetoelastic method. After analyzing the correlation between the stress and the induced voltage, the resonance enhanced magnetoelastic (REME) method was proposed. A REME sensor with a low resonant frequency was made to carry out the experiment. The results showed that the resonant frequency, the resonant voltage, and the induced voltage could be used to measure stress, the test errors were 12.5%, 11.9%, and 9.5%, respectively. To measure stress, the excitation frequency should be close and lower than the resonant frequency. Enhanced by the resonance theory, the sensitivity of the REME method was 132.47% and 286.50% higher than that corresponding to the resonant voltage and the resonant frequency. The REME method has the advantages of low power supply and good dynamic response. Besides, using the resonance theory to enhance the measurement is applied to other coil-based sensors and methods.

A Comparative Performance Analysis of Zero Voltage Switching Class E and Selected Enhanced Class E Inverters

This paper presents a comparative analysis of the class E and selected enhanced class E inverters, namely, the second and third harmonic group of class EFn, E/Fn and the class E Flat Top inverter. The inverters are designed under identical specifications and evaluated against the variation of switching frequency (f), duty ratio (D), capacitance ratio (k), and the load resistance (RL). To offer a comparative understanding, the performance parameters, namely, the power output capability, efficiency, peak switch voltage and current, peak resonant capacitor voltages, and the peak current in the lumped network, are determined quantitatively. It is found that the class EF2 and E/F3 inverters, in general, have higher efficiency and comparable power output capability with respect to the class E inverter. More specifically, the class EF2 (parallel LC and in series to the load network) and E/F3 (parallel LC and in series to the load network) maintain 90% efficiency compared to 80% for class E inverter at the optimum operating condition. Furthermore, the peak switch voltage and current in these inverters are on average 20–30% lower than the class E and other versions for k > 1. The analysis also shows that the class EF2 and E/F3 inverters should be operated in the stretch of 1 < k < 5 and D = 0.3–0.6 at the optimum load to sustain the high-performance standard.

Decreasing the Power-Clock Resonant Signal Central Voltage as a Mean for Power Reduction in Integrated Power and Clock Distribution Networks

Background/Objectives: Density, performance, and design complexity of integrated circuits are rapidly increasing specifically in 3-D integration where multi-plane synchronization is required. The power and clock distribution networks consume a large portion of the limited on-chip metal resources. In order to reduce the metal overhead associated with the power, global clock, and local clock distribution networks, the concept of an integrated power and clock distribution network (IPCDN) was investigated and correct functionality of combinational and sequential elements verified. This study discusses potential power savings in IPCDNs achieved by reducing the central voltage at which the signal oscillates. Methods/Statistical analysis: In this paper, an IPCDN with differential power-clock signals centered at half the supply voltage is proposed to further reduce the power consumption. The elements of the proposed scheme including the LC differential power-clock driver, clamping circuit, clock buffer, and voltage doubler have been simulated using Tanner 0.25 um CMOS technology at a frequency of 50 MHz and a supply voltage of 2.5 V. Findings: Simulation results indicate that the proposed scheme achieves 75.32% and 76.47% power reduction in the LC differential powerclock driver and clock buffer, respectively. The effects of process, voltage supply, and temperature (PVT) variations on the proposed scheme were also investigated. Discussion: The IPCDN has a large capacitance and is heavily loaded, thus reducing the central voltage of the resonant sinusoidal signal flowing in this network enables significant reduction in power consumption. Novelty/Applications: The proposed scheme enables power reductions in the LC differential power clock driver and clock buffer. The effects of process, voltage supply, and temperature (PVT) variations on all circuit elements of the proposed scheme was investigated. Keywords: resonant clocking; power reduction; routing complexity; LC clock driver; clock buffer; clamping circuit; voltage doubler Density, performance, and design complexity of integrated circuits are rapidly increasing specifically in 3-D integration where multi-plane synchronization is required. The power and clock distribution networks consume a large portion of the limited on-chip metal resources. In order to reduce the metal overhead associated with the power, global clock, and local clock distribution networks, the concept of an integrated power and clock distribution network (IPCDN) was investigated and correct functionality of combinational and sequential elements verified. This study discusses potential power savings in IPCDNs achieved by reducing the central voltage at which the signal oscillates. Methods/Statistical analysis: In this paper, an IPCDN with differential power-clock signals centered at half the supply voltage is proposed to further reduce the power consumption. The elements of the proposed scheme including the LC differential power-clock driver, clamping circuit, clock buffer, and voltage doubler have been simulated using Tanner 0.25 um CMOS technology at a frequency of 50 MHz and a supply voltage of 2.5 V. Findings: Simulation results indicate that the proposed scheme achieves 75.32% and 76.47% power reduction in the LC differential powerclock driver and clock buffer, respectively. The effects of process, voltage supply, and temperature (PVT) variations on the proposed scheme were also investigated. Discussion: The IPCDN has a large capacitance and is heavily loaded, thus reducing the central voltage of the resonant sinusoidal signal flowing in this network enables significant reduction in power consumption. Novelty/Applications: The proposed scheme enables power reductions in the LC differential power clock driver and clock buffer. The effects of process, voltage supply, and temperature (PVT) variations on all circuit elements of the proposed scheme was investigated. Keywords: resonant clocking; power reduction; routing complexity; LC clock driver; clock buffer; clamping circuit; voltage doubler

Analysis and design of four-plate capacitive wireless power transfer system for undersea applications

This paper presents a four-plate undersea capacitive wireless power transfer (CPT) system for underwater applications such as autonomous underwater vehicles (AUVs). Generally, a CPT system transfers the power based on electric fields. The complex resonant compensation networks are used to make the CPT system work in the resonant condition. The resonant voltage is always very high. It will be a big challenge to the human safety. In this paper, a virtual electrons periodic reciprocating flow theory is proposed for the CPT system. In one switching cycle, the electrons firstly flow in the forward direction through the forward path and then flow in the inverse direction through the inverse path. The CPT system has been deeply studied with the vacuum dielectric or the air dielectric. However, for the CPT system, there are few papers to show the underwater application. In this paper, an undersea four-plate CPT system is designed and studied in the underwater condition. The two coupling capacitors and other elements of the CPT system could build a closed-loop path. A small value inductor is adapted as a resonant compensation network for the four-plate CPT system. The DC voltage is inverted to the AC voltage in the primary side with the single-phase full-bridge inverter. The resonant voltage is rectified to the DC voltage in the secondary side with the single-phase full-bridge diode rectifier. A 100 W power level CPT system is constructed to verify the theory analysis and the calculation. The theory analysis is verified by the simulated and experimental results. The stable output voltage and load power are achieved in this paper.

Performance Analysis of Novel Bidirectional DC-DC Converter With L-D Based Modified GaN-FET Driver

Gallium nitride (GaN)-FET devices are capable to provide high efficiency operation of dc-dc converter at higher frequency. The major problem of using GaN-FET in dc-dc converter lies in driver stage, which creates switch voltage ringing and high dv/dt during switching event. This creates false triggering of GaN-FET due its inherent low turn on threshold voltage. In this article, a novel nonisolated coupled inductor based bidirectional dc-dc (CIBDC) converter is proposed and tested with a modified inductor diode (L-D) based GaN-FET driver to verify higher efficiency operation as well as low switch voltage ringing and low dv/dt. The proposed converter is capable to provide higher voltage conversion ratios in both buck and boost mode. Due to parallel path structure the input current ripple is also less in the proposed CIBDC. The steady state performance like switch voltage ringing, dv/dt immunity, voltage stress, current stress, efficiency, etc. of this topology is tested on a 250 W prototype using L-D based driver.

B-PO04-079 HEAD-TO-HEAD COMPARISON OF ATRIAL CMR AND VOLTAGE MAPPING FOR PREDICTION CLINICAL OUTCOMES AFTER ATRIAL FIBRILLATION ABLATION

Atrial magnetic resonance imaging and endocardial voltage mapping are clinical tools for assessing atrial fibrosis. Both techniques have been reported to predict arrhythmia recurrence after catheter ablation of atrial fibrillation. However, it is not known how the predictive value of these techniques compare. To compare the predictive value of atrial MRI and atrial voltage mapping for predicting arrhythmia recurrence after catheter ablation of atrial fibrillation. Consecutive patients undergoing first-time atrial fibrillation ablation with prior atrial magnetic resonance imaging and high-density voltage mapping were included. Atrial magnetic resonance imaging and voltage maps were quantified using open source software (Cemrgapp, (www.cemrg.com) and OpenEP (www.openep.io), respectively). Clinical follow-up occurred over a median of 574 days using ECG and Holter monitoring. Paired magnetic resonance imaging and voltage mapping was performed in 122 patients. Linear regression demonstrated increasing low voltage area (<0.5mV) was associated with age, CHADS2VASc score and left atrial volume. However, cox proportional hazards assessment showed that atrial LGE (>3.3SD above the blood pool mean) was a significant predictor of arrhythmia recurrence (HR 1.04, i.e. risk of recurrence increased by 4% for each 1% increase in fibrosis, p = 0.01), where-as low voltage area was not (<0.5mV). Atrial LGE, but not low voltage area was significantly associated with recurrence of atrial fibrillation after ablation. However, low voltage area was closely related to common clinical comorbidities associated with atrial fibrillation.

Comparative study of 0.1Hz very-low frequency withstand voltage test method and traditional method

The o.1Hz very-low frequency withstand voltage test method has the advantages of small equipment size and low power demand, and is used more and more in the power grid, especially in withstand voltage test. However, the effect of this voltage waveform and the traditional test waveform on the insulation assessment is still unclear. This paper compares the difference between 0.1Hz very-low frequency and DC voltage, resonance voltage and oscillating wave voltage in the withstand voltage test. Research indicates that the 0.1Hz very-low frequency withstand voltage test has good equivalence in cables with mechanical "faults", water tree defects in cables and power frequency, and relatively poor equivalence in terms of needle plate electrode insulation defects.

The Partial Discharge Field Test of 1000kV Shunt Reactors

Aiming at the insulation performance field diagnosis of 1000kV shunt reactors, the series resonant withstand voltage test equipment is developed. The test equipment mainly consists of the frequency conversion power supply, the excitation transformer, the series resonant capacitor, the wave blocking resistor and the voltage divider. The resonant frequency is between 30 and 300 Hz, the rated voltage is 1200kV, and the capacity is 1000 kW. During the test, the discharge is monitored at the high voltage bushing terminal and the 1000kV reactor insulation is analyzed. By using the developed test equipment, the 1000kV reactor in 1000kV Xuyi Station is tested, which verifies the validity of the on-site partial discharge measurement test.

Sensorless Control of Voltage Peaks in Class-E Single-Ended Resonant Inverter for Induction Heating Rice Cooker

Single-ended (SE) resonant inverters are widely used as power converters for high-pressure rice cooker induction, with 1200 V insulated-gate bipolar transistors (IGBTs) being used as switching devices for kW-class products. When voltage fluctuations occur at the input stage of an SE resonant inverter, the resonant voltage applied to the IGBT can be directly affected, potentially exceeding the breakdown voltage of the IGBT, resulting in its failure. Consequently, the resonant voltage should be limited to below a safety threshold—hardware resonant voltage limiting methods are generally used to do so. This paper proposes a sensorless resonant voltage control method that limits the increase in the resonant voltage caused by overvoltage or supply voltage fluctuations. By calculating and predicting the resonance voltage through the analysis of the resonance circuit, the resonance voltage is controlled not to exceed the breakdown voltage of the IGBT. The experimental results of a 1.35 kW SE resonant inverter for a high-pressure induction heating rice cooker were used to verify the validity of the proposed sensorless resonant voltage limiting method.

A resonant piezoelectric proportional valve for high-flowrate regulation operated by a bending sandwich actuator

A resonant piezoelectric proportional valve for large flowrate regulation was proposed in this work. The large flowrate of the valve and its proportional regulation under high differential pressure were achieved using a bending sandwich actuator (BSA). First, the configuration and operation principle of the valve were depicted, and its structural parameters were determined by simulated analyses. Then, the theoretical analysis method was accomplished to predict the flowrate, and the direct fluid structure interaction simulation was used to validate the theoretical model. Ultimately, a prototype was fabricated and experimentally measured for the output performances. The results denoted that the output displacement of the BSA under the loaded condition was 91.69 μm when the resonant frequency and voltage were 2.19 kHz and 100 Vp-p; and the corresponding flowrates for the deionized water (DIW) and silicone oil (SLO) were 1.256 L/min and 0.221 L/min at 344.75 kPa. Besides, the cut-off pressures for the DIW and SLO were 289.59 kPa and 310.275 kPa under −300 V0-p; and the leakages were 0.5 mL/min and 0.2 mL/min under 344.75 kPa. This valve is expected to be applied to the cooling systems, hydraulic actuators.

Study of the characteristic differences of positive and negative half-cycles from atmospheric pressure glow discharge driven by resonant AC voltage

There are many advantages in obtaining low-temperature plasmas that are rich in active particles by atmospheric pressure glow discharge, so there has been a lot of research on the acquisition method and application of it. However, there is a lack of knowledge about the mechanism of atmospheric pressure glow discharge driven by an AC resonant power supply. In this paper, we describe our study of the characteristic differences between half-cycle positive and negative atmospheric pressure glow discharges driven in open air by an AC resonant power supply, and we describe our analysis of the associated physical mechanism. The comparison and analysis of experimental results indicate that both positive-cycle and negative-cycle discharges led to typical glow discharge and no streamer discharge appeared in the discharge process. There were still charged particles in the discharge channel when the discharge current was zero. With increasing amplitude of the output voltage of the power supply, the glow area near the electrode surface and the plasma distribution area in the discharge channel increased. When the output voltage of the power supply was low, the negative polarity discharge was more likely to form in the gap of the pin-to-plate electrode. In the AC discharge process, the α-mode discharge was dominant, and the developing speed of the positive-cycle discharge was faster than that of the negative-cycle discharge. The polarity effect became less obvious with the increase in the output voltage amplitude of the power supply.

Development of virtual instrument model for parameter estimation of fractal antenna array

AbstractThis paper presents the parameter estimation of the fractal antenna array with the virtual instrument model designed in laboratory virtual instrument engineering workbench software. In this work resonant frequency, gain and voltage standing wave ratio have been used as an output parameter with the change in three input parameters such as radius of a circular patch, height of substrate, and dielectric constant of the material. Measured output parameters have been compared with neural network outputs and error has been represented in a graphical way for each output parameter of the antenna array. Along with output parameter estimation, a designing parameter such as radius of the circular patch has also been estimated with virtual instrument model and absolute error for radius has been shown in the display window of the designed model. The proposed antenna array has been fabricated and simulated results have been validated with measured results.