State Feedback Control Based Seamless Switch Control for Microgrid Inverter

With the wide application of distributed generations (DGs) and microgrids (MGs), the inverter control becomes a hot research topic. For the inverter control in MG applications, first, a complex variable state-feedback-based switch control frame is proposed. In the proposed control frame, the state feedback leads to a generalized control objective (GCO), and then the instantaneous voltage and current controls are designed based on the GCO. Finally, a complex variable frequency-locked loop (FLL) is adopted to realize the voltage and current reference computation. The control system is integrated by complex variables to alleviate the seamless switch. The effectiveness of the proposed control method is validated by experimental results.

The sleep EEG envelope: a novel, neuronal firing-based human biomarker

Sleep EEG reflects instantaneous voltage differences relative to a reference, while its spectrum reflects the degree to which it is comprised of oscillations at various frequencies. In contrast, the envelope of the sleep EEG reflects the instantaneous amplitude of oscillations at specific frequencies, and its spectrum reflects the rhythmicity of the occurrence of these oscillations. The ordinary sleep EEG and its spectrum have been extensively studied and its individual stability and relationship to various demographic characteristics, psychological traits and pathologies is well known. In contrast, the envelope spectrum has not been extensively studied before. In two studies, we explored the generating mechanisms and utility of studying the envelope of the sleep EEG. First, we used human invasive data from cortex-penetrating microelectrodes and subdural grids to demonstrate that the sleep EEG envelope spectrum reflects local neuronal firing. Second, we used a large database of healthy volunteers to demonstrate that the scalp EEG envelope spectrum is highly stable within individuals, especially in NREM sleep, and that it is affected by age and sex. Multivariate models based on a learning algorithm could predict both age (r=0.6) and sex (r=0.5) with considerable accuracy from the EEG envelope spectrum. With age, oscillations characteristically shifted from a 4-5 second rhythm to higher rhythms. The envelope spectrum was not associated with general cognitive ability (IQ). Our results demonstrate that the sleep envelope spectrum is a promising, neuronal firing-based biomarker of various demographic and disease-related phenotypes.

Higher harmonics of zero sequence current and voltage as a source of information for single-phase earth fault protection.

Single-phase earth faults in networks with ungrounded neutral are common and belong to a wider class of high-impedance damage. The problem of protection against such damage is quite complex and has been actively studied around the world in recent decades. In this article, it is proposed to use the information contained in the high-frequency components of the current and voltage of the zero-sequence during the transient process of insulation damage for targeted protection. The method of selection of high-frequency components is considered. The possibility of using a Petersen coil in the network is considered, as well as the probable deviation from the resonant tuning of the Petersen coil. The peculiarities of the transient process depending on the instantaneous voltage at the moment of a short circuit are investigated. Simulation of single-phase short circuits with different active resistance in the short circuit place is carried out. The spectral composition of zero-sequence currents and voltages during the transient process is analyzed. The dependence of the power of high-frequency components on the quality of Petersen coil tuning, instantaneous voltage at the time of short circuit, and active resistance at the time of short circuit is investigated. The principle of protection is based on determining the direction of the total reactive power of the higher harmonics of currents and voltages of zero sequence and the numerically found derivatives. The results of mathematical modeling showed that at the moment when the phase is closed to the ground, due to the recharging of the capacitance of the phase conductors in currents and voltages of zero sequence, higher harmonics occur. The power of the harmonics from the second to the tenth can be compared with the power of the first harmonic and they should be used for protection. Positive results of work of the offered way of protection at mathematical modeling and at tests on a laboratory stand are received.

Process of Multiple Channel Gliding Arc Assisted Combustion Near Lean Blow-out Limit

Multichannel gliding arcs actuators were designed to enhance the non-premixed combustion of the kerosene (RP-3) and air mixture in a swirl combustor near lean blow-out limit. The instantaneous voltage and current of the multichannel gliding arcs and the 1kHz high-speed CH* chemiluminescence imaging of the combustion process were simultaneously measured to show the characteristics of the process assisted by the plasma. When reaching near lean blow-out limit in a flow rate of 225 SLPM, at the combustor inlet, the emission intensity and projected flame assisted by the multichannel gliding arcs remain the same with decreased fuel flow rates from 3 to 1 ml/min, which assisted by the single gliding arc decreases nevertheless. The flame structure under the influence of plasma actuators with various channel numbers evolves differently owing to the differences in plasma distributions.

A vertical wind turbine monitoring system using commercial online digital dashboard

The output of a green energy generator is required to be monitor continuously. The monitoring process is important because the performance of the energy gen- erator needs to be known and evaluate. However, monitoring the generator manu- ally and efficiently is troublesome. Moreover, when most of the energy generator located at uneasy to reach or at a very remote place. Added to the cost, human intervention for the monitoring process contributes to the unnecessary bill. All the highlighted limitations can be overcome using an internet cloud base system and application. Most of the existing data logging instruments use a memory card or personal computer in their operation. The stored data is accessible only at a dedicated computer alone. This work presented a complete energy generator interface with a commercial online digital dashboard. The digital dashboard, parameters of the wind turbine, such as the amount of power generates and the magnitude of instantaneous voltage can be monitored, and the recorded data can be accessed quickly, at any time and anyplace.

Application of Sliding Mode Control Technique to Regulate DC/DC Boost Converters in Systems Exploiting Photovoltaic Power Generation

<p class="Abstract">This paper introduces a new method, called IB-SMC method, to control DC/DC boost converters in systems exploiting photovoltaic power generation. This method combines the sliding mode control technique and iterative-bisectional technique in the maximum power point tracker to change operations modes of photovoltaic power generation. The IB-SMC controller uses voltage sliding surface to evaluate the relation of instantaneous voltage at the input converter and instantaneous voltage at the maximum power point. Using information about the power of electromagnetic radiation from a pyranometer and temperature from a temperature sensor, the sliding surface and hyteresis band are changed by practically operational conditions that help improving energy efficiency of the process exploiting PVg. Simulations are carried out by Matlab/Simulink that show the ability to ensure dynamic stability by tracking instaneous maximum power point at any time whenever having any change of the operational condition, static stability by maintaining the operation point at maximum power point whenever not have any change of the operational condition and help to bring out approximately absolute energy efficiency.</p>