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All Journal International Journal of Electrical and Computer Engineering TELKOMNIKA (Telecommunication Computing Electronics and Control)

Fredy E. Hoyos Velasco

Universidad Nacional de Colombia

Author-ID : 2373806

Computer Science & IT Electrical & Electronics Engineering

Published : 6 Documents Claim Missing Document

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Articles

DC-AC power inverter controlled analogically with zero hysteresis Fredy E. Hoyos Velasco; Carlos I. Hoyos Velasco; John E. Candelo-Becerra
International Journal of Electrical and Computer Engineering (IJECE) Vol 9, No 6: December 2019
Publisher : Institute of Advanced Engineering and Science

This paper presents the design and experimental validation of a DC-AC power inverter, controlled analogically with zero hysteresis. A control circuit was built using analog electronics components, and optocoupler devices are used to couple the control module with the power stage. The design of DC-AC inverter with electronics circuit and implementation are shown in detail. Experimental results show the effectiveness of control technique and implementation, leading to a robust system concerning load disturbances. The developed inverter offers the possibility of generating regulated output voltages of different signal types, both DC and AC, variable in frequency and in amplitude, useful for feeding a load with various AC signals.

Optimal parameters of inverter-based microgrid to improve transient response Sergio Andrés Pizarro Pérez; John E. Candelo-Becerra; Fredy E. Hoyos Velasco
International Journal of Electrical and Computer Engineering (IJECE) Vol 10, No 1: February 2020
Publisher : Institute of Advanced Engineering and Science

The inertia issues in a microgrid can be improved by modifying the inverter control strategies to represent a virtual inertia simulation. This method employs the droop control strategy commonly used to share the power of a load among different power sources in the microgrid. This paper utilizes a modified droop control that represents this virtual inertia and applies an optimization algorithm to determine the optimal parameters and improve transient response. The results show better control when different variations are presented in the loads, leading the microgrid to have a better control of the operation. The optimization method applied in this research allows improvement to the transient response, thus avoiding unnecessary blackouts in the microgrid.

Reactive power sharing in microgrid using virtual voltage Eder A. Molina-Viloria; John E. Candelo Becerra; Fredy E. Hoyos Velasco
International Journal of Electrical and Computer Engineering (IJECE) Vol 11, No 4: August 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v11i4.pp2743-2751

The traditional droop control strategy has been applied previously in microgrids (MGs) to share accurately the active power. However, in some cases the result obtained when sharing reactive power is not the best, because of the parameters related to the distances from distributed generators (DGs) to the loads and the power variations. Therefore, this paper proposes a reactive power control strategy for a low voltage MG, where the unequal impedance related to the distances between generators and loads requires adjustments to work with the conventional frequency and voltage droop methods. Thus, an additional coefficient is calculated from parameters of the network that relate the location of elements. The test is perfomed by simulations in the MATLAB-Simulink software, considering a three-node MG with three DGs and a load that can change power at different periods of time. The results show that it is possible to improve reactive power sharing between the DGs located in the MG according to the load changes simulated and to improve voltages with this method.

Unsteady state series CSTR modeling of removal of ammonia nitrogen from domestic wastewater treated in a vertical flow constructed wetland Alejandro Rincón; Gloria Yaneth Florez; Fredy E. Hoyos Velasco
International Journal of Electrical and Computer Engineering (IJECE) Vol 10, No 1: February 2020
Publisher : Institute of Advanced Engineering and Science

This work shows simulation results for subsurface vertical flow constructed wetland (VFCW) using a series CSTR model. The VFCW considered received the outflow from a domestic wastewater treatment plant. In addition, it was planted with Cyperus sp. and filter media was unsaturated. The model was based on an unsteady state mass balance for ammonia, nitrites, and nitrates, using one to three series CSTRs. Nitrogen transformation mechanisms considered were ammonification, nitrification, plant uptake and denitrification. The following effects were evaluated: the number of reacting CSTRs from one to three; the occurrence of the reaction in second and third CSTRs for the case that three CSTRs hold; the use of either equal or different values of reaction rate parameters between CSTRs; and the discretization of the reaction rate parameters. The inflow and outflow measurements of ammonium, nitrites, and nitrates were used for model calibration. The estimated parameters included the reaction rate coefficients and reactor water volume. The coefficient of determination (R2) evidenced a satisfactory capability of simulating outlet pollutant concentrations. Two and three reacting CSTRs achieved similar R2 value (0.54-0.55), whereas one reacting CSTR achieved an R2 of 0.39, and three CSTRs with reaction only in the first tank achieved an R2 of 0.42. Discretization of the nitrification rate for the case of two reacting CSTRs led to an R2 of 0.94. The parameter sensitivity analysis revealed a significant effect of model parameters on the R2 value.

Fractal representation of the power demand based on topological properties of julia sets Hector A. Tabares-Ospina; John E. Candelo-Becerra; Fredy E. Hoyos Velasco
International Journal of Electrical and Computer Engineering (IJECE) Vol 9, No 4: August 2019
Publisher : Institute of Advanced Engineering and Science

In a power system, the load demand considers two components such as the real power (P) because of resistive elements, and the reactive power (Q) because inductive or capacitive elements. This paper presents a graphical representation of the electric power demand based on the topological properties of the Julia Sets, with the purpose of observing the different graphic patterns and relationship with the hourly load consumptions. An algorithm that iterates complex numbers related to power is used to represent each fractal diagram of the load demand. The results show some representative patterns related to each value of the power consumption and similar behaviour in the fractal diagrams, which allows to understand consumption behaviours from the different hours of the day. This study allows to make a relation among the different consumptions of the day to create relationships that lead to the prediction of different behaviour patterns of the curves.

Buck converter controlled with ZAD and FPIC for DC-DC signal regulation Fredy E. Hoyos Velasco; Yeison Alberto Garcés Gómez; John E. Candelo-Becerra
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 1: February 2020
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v18i1.14108

This paper presents the performance of a fixed-point induction control (FPIC) technique working in conjunction with the non-linear control technique called zero average dynamics (ZAD) to control chaos in a buck converter. The control technique consists of a sliding surface in which the error tends to zero at each sampling period. A switch is controlled by using centered pulse width modulation (CPWM) control signal. The converter controlled with ZAD-FPIC has been simulated in Matlab and implemented using rapid control prototyping (RCP) in a DSP to make comparisons between simulation and experimental tests. To perform this comparison, some variations in the control parameter and the voltage reference are made in order to evaluate the performance of the system. Results are obtained with errors lower than 1 % which demonstrates the good performance of the control techniques.

Co-Authors Alejandro Rincón Carlos I. Hoyos Velasco Eder A. Molina-Viloria Gloria Yaneth Florez Hector A. Tabares-Ospina John E. Candelo Becerra John E. Candelo-Becerra Sergio Andrés Pizarro Pérez Yeison Alberto Garcés Gómez

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