Rafael Pena-Gallardo

Harmonic Issues Assessment on PWM VSC-Based Controlled Microgrids Using Newton Methods

This paper presents the application of Newton-based methods in the time-domain for the computation of the periodic steady state solutions of microgrids with multiple distributed generation units, harmonic stability, and power quality analysis. Explicit representation of the commutation process of the power electronic converters and closed-loop power management strategies are fully considered. Case studies under different operating scenarios are presented: grid-connected mode, islanded mode, variations in the Thevenin equivalent of the grid and the loads. Besides, the close relation between the harmonic distortion, steady state performance of the control systems, asymptotic stability, and power quality is analyzed in order to evaluate the importance and necessity of using full models in stressed and harmonic distorted scenarios.

Robust stability analysis for a power system stabilizer

This contribution presents the robust stability tests for a Power System Stabilizer (PSS) of the type PSS1A under two different modeling of uncertainties. The PSS is a supplementary excitation controller used to damp electromechanical oscillations that appear in a synchronous generator. Using an unstructured uncertainty modeling the limits of stability of the PSS1A are found. The proposed tests are explained and validated through simulation.

Low voltage ride-through analysis in real time of a PV-Wind hybrid system

This paper presents a full model of a PV-Wind hybrid system implemented in a Real Time Digital Simulator (RTDS). The control strategies used for the connection of the hybrid system with the grid were developed and implemented in an Arduino Due board. The Hardware-in-the-loop (HIL) technique was used to interface the RTDS with the Arduino Due board. This model was developed in order to evaluate the Low Voltage Ride through (LVRT) requirements of renewable energy systems that are connected with the grid. Case studies that show the performance of the control systems, and the LVRT requirements that are accomplished under fault conditions are presented.

A Comprehensive Modeling of a Three-Phase Voltage Source PWM Converter

This contribution reports the development of a time domain model of a three-phase voltage source converter (VSC) that can be used in the transient and steady state analysis of nonlinear power systems including their associated closed-loop control schemes. With this proposed model, the original discontinuous nonlinear power system can be transformed into a continuous system, while keeping the underlying harmonic nature of the VSC and avoiding typical and undesirable numerical problems associated with the large derivatives during the switching transitions. The development of this model was based on the dynamic Fourier series of the switching functions under a sinusoidal PWM modulation scheme, which require the calculation of the switching instants at each integration step; the switching instants and the dynamic Fourier series coefficients are calculated by explicit mathematical formulas. The proposed model of the VSC is suitable for the fast computation of the periodic steady state solution through the application of Newton method. Simulations were carried out in order to illustrate the benefits of the proposed VSC model.

A comparative study of the application of FACTS devices in wind power plants of the southeast area of the Mexican electric system

This paper presents a comparative study of the application of Flexible AC Transmission System (FACTS) devices, as Thyristor Controlled Series Capacitor (TCSC), Static Synchronous Compensator (STATCOM) and Unified Power Controller (UPFC) on congestion management and voltage support in the area of the Istmo of Tehuantepec, Oaxaca, Mexico. The present work provides an analysis about the performance of the control of active and reactive power of the FACTS controllers applied to mentioned problems in the power system.

Uncertainty modeling of a PSS3B Power System Stabilizer

Power systems are dynamic systems subject to disturbances, which can lead to unstable system operating conditions. For that, the Power System Stabilizer (PSS), which it is a complementary excitation controller, is used for damping electromechanical oscillations present in the power system, ensuring stability. In this paper, a robust stability test is proposed for the PSS3B stabilizer using an unstructured modeling. The limits of stability of the PSS3B stabilizer are found using additive uncertainty for a Single-Input Multiple-Output (SIMO) model. The proposed test is explained and is validated through simulations.

Optimized design of a quadratic boost converter based on the R 2 P 2 principle

In this paper is presented the optimal design of a switching boost converter based on the reduced redundant power processing (R2P2) principle. Using the NSGA-II optimization method is found a set of optimal combinations for the converter parameters (inductors and capacitors), such that the open loop performance of the converter is improved. The constraints associated to current/voltage ripples and zero-pole locations are used to improve the design. Simulation results show that the optimized converter can be easily controlled with only one control loop.

Modeling of a wind turbine with a permanent magnet synchronous generator for real time simulations

This paper presents a mathematical model of a wind turbine that includes a permanent magnet synchronous machine (PMSG) for real time simulations. The dynamic model considers a stochastic model of the wind, a state-space representation of the wind turbine with the PMSG, avoiding the use of a gear box, and a back-to-back converter for the interconnection of system with the grid. A field oriented control technique in the dq reference frame was used for the converter, also a control loop for the pitch angle of the wind turbine was implemented. In order to show the performance of the controllers, they were implemented in an Arduino card and then connected to a specialized station in real time simulations. Case studies that show the dynamic behavior of the wind turbine are presented and discussed.

Stability and harmonic assessment of a controlled microgrid using newton methods

This paper presents the accelerated computation of the periodic steady state solutions of a nonlinear controlled microgrid system with multiple distributed generation units, using six Newton methods. The performance of the Newton methods are compared in terms of their numerical properties, computational effort and efficiency in order to know their advantages and disadvantages in the computation of the periodic steady state solution of microgrids. The commutation of the power electronic converters and the closed-loop power management control are explicitly considered in the computed solution. Simulation results are presented to evaluate the Newton methods.