Omar Pinzón-Ardila

This paper presents the detailed design, analysis, and application of the controller for a shunt active power filter based on a pulsewidth modulation dc-to-ac voltage source converter. The controller is mainly tailored to compensate harmonic currents of nonlinear loads connected to the mains. However, it can also achieve reactive-power compensation and mains-current balancing when required. The controller has a two-layer structure. The outer layer generates the current references for the inner layer. The former uses a plug-in discrete-time repetitive algorithm for current-harmonic compensation, a proportional-integral algorithm to maintain the dc-capacitor voltage in spite of unmodeled losses and a reactive-power-reference generator. The inner layer uses state-feedback with integral action for current control. The repetitive controller is justified to improve the tracking of the periodic current references required by the active filters. The stability of the resulting closed-loop system is studied and some indication of the system robustness is given. The proposed controller has been tested in a prototype with balanced and unbalanced nonlinear loads. A discrete-time model of the filter has been used from the beginning. The microcomputer delay when calculating the controller output and the delay due to the anti-aliasing filters have been included in the inner system state-variable model

Real time operating systems have been evolving in gigantic steps, allowing, each time to develop applications where some restrictions on task execution time are needed. In this article xPC Target is shown as a new option for control, going through basic concepts of real time to come up with a highly used application in robotics as well as in general industry; which is a speed control for a DC motor. This application links xPC Target as a real time operating system in charge of executing a control task, besides it integrates a based FPGA I/O board which interacts with the controller and outside environment. This is how xPC Target delivers a form of systems optimization, since, rapid prototyping platforms, embedded systems, real time operating systems and also programming algorithms from MatLab and Simulink are integrated.

<p>Presenta un estudio comparativo entre el Control Predictivo basado en el Modelo [MPC] y el control PID, en una planta piloto de temperatura. Se encontró que el control MPC presenta mejor comportamiento, con un tiempo de asentamiento de 1000 segundos y una sobre-elongación de 5 °C, y que el PID presenta un tiempo de asentamiento de 2000 segundos y una sobre-elongación de 40 °C. Simultáneamente, se presenta una forma alternativa para controlar y monitorear en tiempo real la variable temperatura; para ello se dispone de un computador de escritorio que utiliza el software MATLAB 7.1 y la herramienta Real-Time Windows Target.</p>

This paper presents the analysis and the application of a current controller in an active power filter (APF) based on a PWM voltage-source electronic converter with three legs and four wires. The neutral wire is connected to the middle point of the DC-capacitor voltage. The controller proposed here is an extension of the one proposed for a three-wire shunt active power filter. The controller is a two-level nested controller. The outer-loop generates the reference current for the inner-loop. The latter, is a state-feedback current controller with integral action. The former consists of (i) a selective harmonic elimination technique and (ii) a DC-capacitor-voltage controller. This paper will focus on the neutral-wire current control and on the balance control of the DC-capacitor voltage. The performance of the control algorithm has been demonstrated using a test-rig with balanced and non-balanced non-linear loads.

The smart transformer (ST) is a multiport and multi-stage converter that allows for the formation of meshed hybrid microgrids (MHMs) by enabling AC-DC ports in medium and low voltage. This type of microgrid has advantages over the performance of conventional hybrid AC-DC microgrids (HMGs); however, the number of degrees of freedom of the ST increases the complexity of the energy management systems (EMSs), which require adequate and accurate modeling of the power flow of the converters and the MG to find the feasible solution of optimal power flow (OPF) problems in the MHM. An ST’s equivalent power flow model is proposed for formulating the MHM OPF problem and developing low-frequency equivalent models integrated with a decoupled hierarchical control architecture under a real-time simulation approach to the ST-based MHM. A simulation model of the MHM in the Simulink® environment of Matlab® 9.12 is developed and implemented under a digital real-time simulation (DRTS) approach on the OPAL-RT® platform. This model allows for determining the accuracy of the developed equivalent models, both low-frequency and power flow, and determining the MHM performance based on optimal day-ahead scheduling. Simulation test results demonstrated the ST equivalent model’s accuracy and the MHM’s accuracy for OPF problems with an optimal day-ahead scheduling horizon based on the model-in-the-loop (MIL) and DRTS approach.