scholarly journals Robust Digital Control for an LLC Current-Resonant DC-DC Converter

1970 ◽  
Vol 7 (1) ◽  
pp. 71-78
Author(s):  
Tomoya Nishimura ◽  
Yuto Adachi ◽  
Yoshihiro Ohta ◽  
Kohji Higuchi ◽  
Eiji Takegami ◽  
...  
Keyword(s):  
Output Voltage ◽  
Sudden Change ◽  
Experimental Studies ◽  
Load Resistance ◽  
Pulse Frequency ◽  
Step Response ◽  
Response Characteristics ◽  
Change Dynamics ◽  
Voltage Variation ◽  
Single Controller

If a pulse frequency and a load resistance of an LLC current-resonant DC-DC converter are changed, the dynamic characteristics are varied greatly, that is, the LLC current-resonant DC-DC converter has non-linear characteristics. In many applications of DC-DC converters, loads cannot be specified in advance, and they will be changed suddenly from no loads to full loads. A DC-DC converter system used a conventional single controller cannot be adapted to change dynamics and it occurs large output voltage variation. In this paper, a robust digital controllerfor suppress the change of step response characteristics and variation of output voltage in the load sudden change is proposed. Experimental studies using a micro-processor for the controller demonstrate that this type of digital controller is effective to suppress the variation.

scholarly journals Robust Digital Control for Interleaved PFC Boost Converter Using Approximate 2DOF

1970 ◽  
Vol 8 (2) ◽  
pp. 187-194
Author(s):  
Yuki Satake ◽  
Hiroyuki Furuya ◽  
Yohei Mochizuki ◽  
Yuji Fukaishi ◽  
Kohji Higuchi ◽  
...  
Keyword(s):  
Power Factor ◽  
Output Voltage ◽  
Sudden Change ◽  
Experimental Studies ◽  
Input Voltage ◽  
Boost Converter ◽  
Buck Converter ◽  
Digital Controller ◽  
Step Response ◽  
Duty Ratio

In recent years, improving of power factor and reducing harmonic distortion in electrical instruments are needed. In general, a current conduction mode boost converter is used for active PFC (Power Factor Correction). In a PFC boost converter, if a duty ratio, a load resistance and an input voltage are changed, the dynamic characteristics are varied greatly. This is the prime reason of difficulty of controlling the interleaved PFC boost converter. In this paper, a robust digital controller for suppressing the change of step response characteristics and variation of output voltage at a DC-DC buck converter load sudden change with high power factor and low harmonic is proposed. Experimental studies using a micro-processor for controller demonstrate that the proposed digital controller is effective to improve power factor and to suppress output voltage variation.

scholarly journals Analysis and Implementation of a Frequency Control DC–DC Converter for Light Electric Vehicle Applications

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1623
Author(s):  
Bor-Ren Lin
Keyword(s):  
Electric Vehicles ◽  
Output Voltage ◽  
Frequency Control ◽  
Input Voltage ◽  
Pulse Frequency ◽  
Switching Frequency ◽  
Battery Charger ◽  
Dc Microgrid ◽  
Load Voltage ◽  
Transportation Vehicle

In order to realize emission-free solutions and clean transportation alternatives, this paper presents a new DC converter with pulse frequency control for a battery charger in electric vehicles (EVs) or light electric vehicles (LEVs). The circuit configuration includes a resonant tank on the high-voltage side and two variable winding sets on the output side to achieve wide output voltage operation for a universal LEV battery charger. The input terminal of the presented converter is a from DC microgrid with voltage levels of 380, 760, or 1500 V for house, industry plant, or DC transportation vehicle demands, respectively. To reduce voltage stresses on active devices, a cascade circuit structure with less voltage rating on power semiconductors is used on the primary side. Two resonant capacitors were selected on the resonant tank, not only to achieve the two input voltage balance problem but also to realize the resonant operation to control load voltage. By using the variable switching frequency approach to regulate load voltage, active switches are turned on with soft switching operation to improve converter efficiency. In order to achieve wide output voltage capability for universal battery charger demands such as scooters, electric motorbikes, Li-ion e-trikes, golf carts, luxury golf cars, and quad applications, two variable winding sets were selected to have a wide voltage output (50~160 V). Finally, experiments with a 1 kW rated prototype were demonstrated to validate the performance and benefits of presented converter.

scholarly journals Analytical Modeling of a Doubly Clamped Flexible Piezoelectric Energy Harvester with Axial Excitation and Its Experimental Characterization

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  
Keyword(s):  
Output Power ◽  
Power Output ◽  
Output Voltage ◽  
Energy Harvester ◽  
Load Resistance ◽  
Engineering Practice ◽  
Maximum Output ◽  
Widespread Application ◽  
Piezoelectric Energy ◽  
Axial Excitation

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.

scholarly journals Voltage Tracking Control of DC- DC Boost Converter Using Fuzzy Neural Network

2018 ◽  
Vol 9 (4) ◽  
pp. 1657 ◽  
Author(s):  
Waleed Ishaq Hameed ◽  
Baha Aldeen Sawadi ◽  
Ali Muayed
Keyword(s):  
Neural Network ◽  
Tracking Control ◽  
Output Voltage ◽  
Fuzzy Neural Network ◽  
Sudden Change ◽  
Input Voltage ◽  
Boost Converter ◽  
Data Sets ◽  
Fuzzy Neural ◽  
Output Load

<span lang="EN-US">This paper deals with voltage tracking control of DC- DC boost converter based on Fuzzy neural network. Maintaining the output voltage of the boost converter in some applications are very important, especially for sudden change in the load or disturbance in the input voltage. Traditional control methods usually have some disadvantages in eliminating these disturbances, as the speed of response to these changes is slow and thus affect the regularity of the output voltage of the converter. The strategy is to sense the output voltage across the load and compare it with the reference voltage to ensure that it follows the required reference voltages. In this research, fuzzy neural was introduced to achieve the purpose of voltage tracking by training the parameter of controller based on previous data. These data sets are the sensing input voltage of the converter and the value of the output load changes. To establish the performance of proposed method, MATLAB/SIMULINK environments are presented, simulation results shows that proposed method works more precisely, faster in response and elimination the disturbances</span>

scholarly journals Advanced Performance Metrics and Sensitivity Analysis for Model Validation and Calibration

2020 ◽  
Author(s):  
Urmila Agrawal ◽  
Pavel Etingov ◽  
Renke Huang
Keyword(s):  
Sensitivity Analysis ◽  
Power Systems ◽  
Model Validation ◽  
Real World ◽  
Model Calibration ◽  
Dynamic Models ◽  
Performance Metrics ◽  
Step Response ◽  
Response Characteristics ◽  
Oscillatory Response

<pre>High quality generator dynamic models are critical to reliable and accurate power systems studies and planning. With the availability of PMU measurements, measurement-based approach for model validation has gained significant prominence. Currently, the model validation results are analyzed by visually comparing real--world PMU measurements with the model-based response measurements, and parameter adjustments rely mostly on engineering experience. This paper proposes advanced performance metrics to systematically quantify the generator dynamic model validation results by separately taking into consideration slow governor response and comparatively fast oscillatory response. The performance metric for governor response is based on the step response characteristics of a system and the metric for oscillatory response is based on the response of generator to each system mode calculated using modal analysis. The proposed metrics in this paper is aimed at providing critical information to help with the selection of parameters to be tuned for model calibration by performing enhanced sensitivity analysis, and also help with rule-based model calibration. Results obtained using both simulated and real-world measurements validate the effectiveness of the proposed performance metrics and sensitivity analysis for model validation and calibration.</pre>

scholarly journals Experimental Study on Piezoelectric Energy Harvesting from Vortex-Induced Vibrations and Wake-Induced Vibrations

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Min Zhang ◽  
Junlei Wang
Keyword(s):  
Energy Harvesting ◽  
Output Voltage ◽  
Maximum Output Power ◽  
Load Resistance ◽  
Maximum Output ◽  
Piezoelectric Energy ◽  
Vortex Induced Vibrations ◽  
Flow Induced Vibrations ◽  
Generation Capacity ◽  
Output Characteristics

A rigid circular cylinder with two piezoelectric beams attached on has been tested through vortex-induced vibrations (VIV) and wake-induced vibrations (WIV) by installing a big cylinder fixed upstream, in order to study the influence of the different flow-induced vibrations (FIV) types. The VIV test shows that the output voltage increases with the increases of load resistance; an optimal load resistance exists for the maximum output power. The WIV test shows that the vibration of the small cylinder is controlled by the vortex frequency of the large one. There is an optimal gap of the cylinders that can obtain the maximum output voltage and power. For a same energy harvesting device, WIV has higher power generation capacity; then the piezoelectric output characteristics can be effectively improved.

Theoretical and experimental studies of a piezoelectric ring energy harvester

2019 ◽  
Vol 30 (7) ◽  
pp. 998-1009 ◽  
Author(s):  
XF Zhang ◽  
HS Tzou
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Output Voltage ◽  
Laboratory Experiments ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Experimental Studies ◽  
Design Parameters ◽  
Resistive Load ◽  
Practical Applications

Based on the electromechanical coupling of piezoelectricity, a piezoelectric ring energy harvester is designed and tested in this study, such that the harvester can be used to power electric devices in the closed-circuit condition. Output energies across the external resistive load are evaluated when the ring energy harvester is subjected to harmonic excitations, and various design parameters are discussed to maximize the power output. In order to validate the theoretical energy harvesting results, laboratory experiments are conducted. Comparing experiment results with theoretical ones, the errors between them are under 10% for the output voltage. Laboratory experiments demonstrate that the ring energy harvester is workable in practical applications.

scholarly journals Nonlinear response characteristics of neural networks and single neurons undergoing optogenetic excitation

2020 ◽  
Vol 4 (3) ◽  
pp. 852-870
Author(s):  
Jannik Luboeinski ◽  
Tatjana Tchumatchenko
Keyword(s):  
Neural Networks ◽  
Nonlinear Response ◽  
Pulse Frequency ◽  
Simulation Code ◽  
Response Characteristics ◽  
Optogenetic Stimulation ◽  
Spatial Response ◽  
Temporal And Spatial ◽  
Light Beams ◽  
Indirect Stimulation

Optogenetic stimulation has become the method of choice for investigating neural computation in populations of neurons. Optogenetic experiments often aim to elicit a network response by stimulating specific groups of neurons. However, this is complicated by the fact that optogenetic stimulation is nonlinear, more light does not always equal to more spikes, and neurons that are not directly but indirectly stimulated could have a major impact on how networks respond to optogenetic stimulation. To clarify how optogenetic excitation of some neurons alters the network dynamics, we studied the temporal and spatial response of individual neurons and recurrent neural networks. In individual neurons, we find that neurons show a monotonic, saturating rate response to increasing light intensity and a nonmonotonic rate response to increasing pulse frequency. At the network level, we find that Gaussian light beams elicit spatial firing rate responses that are substantially broader than the stimulus profile. In summary, our analysis and our network simulation code allow us to predict the outcome of an optogenetic experiment and to assess whether the observed effects can be attributed to direct or indirect stimulation of neurons.

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