LPV Control of Current Source Inverter synchronized with the grid

Power inverters are widely used in grid connected applications, specially with the increasing use of renewable energies, to improve power quality and increase efficiency. However some parameter associated to the grid and/or the inverters, such as the grid frequency, needs to be known or properly estimated. This estimation introduces an uncertainty in the system and suffer transients due to the estimator. Linear Parameter Varying (LPV) control can be used to account for those uncertainties. This paper presents a feedback control based on a LPV control law to improve the power quality of a grid connected Current Source Inverter (CSI), significantly reducing the total harmonic distortion (THD) of the grid generator current. A linear model of the interconnection is presented, where the frequency of the grid is assumed variable being estimated together with its phase through a Phase Locked Loop (PLL). The LPV control law is implemented through state feedback achieving both, harmonic suppression and reference tracking, using the estimation of the frequency of the PLL. Implicitly, this allows for the estimation of the magnitude and phase of the harmonic distortion canceling it up to the CSI current limit. An analytic proof of the filtering guarantees of the method is presented along with simulation results that show the practical viability of this technique. It is shown that this control approach is capable of an appealing adaptation to changes in the frequency of the power grid with a low computational burden being able to also cope with disturbances in the estimation of the frequency due to the PLL.Fil: Ghersin, Alejandro Simon. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Cossutta, Pablo Martín. Instituto Tecnológico de Buenos Aires. Facultad de Ingeniería. Departamento de Electrónica. Centro de Investigación y Desarrollo en Electrónica Industrial; ArgentinaFil: Aguirre, Miguel Pablo. Instituto Tecnológico de Buenos Aires. Facultad de Ingeniería. Departamento de Electrónica. Centro de Investigación y Desarrollo en Electrónica Industrial; Argentin

Control system to balance internal currents of a multilevel current-source inverter

Multilevel current-source inverters have proved to be a high-performance option for industrial applications due to reliability, fault-tolerant capabilities, quasi soft switching, and the use of lower filter capacitor values. One of its major challenges is to balance the internal currents that feed each module. Imbalances could be caused by manufacturing deviations of the reactive components, temperature drift or aging, nonlinear loads, and modulation errors, among others. Using the well-known phase-shift carrier sinusoidal pulse width modulation, a slight change in the amplitude of the carrier signals produces a variation in the average value of the internal currents. In this paper, we introduce a control strategy to balance the current of the inductors and its implementation in a prototype. Simulation and experimental results at different operating conditions show a robust behavior of the control system along with a low distortion in the output voltages and currents of the converter.Fil: Cossutta, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Aguirre, Miguel Pablo. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Angelico Engelhardt, Mathias. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Valla, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata; Argentin

Single-Stage Fuel Cell to Grid Interface with Multilevel Current-Source Inverters

Renewable energy sources can be used for electric power generation to supply specific devices in distributed systems such as smart grids. Hydrogen fuel cells have proven to be an effective solution to produce electrical energy with fairly good efficiency and minimum environmental pollution. A single-stage solution to interconnect a fuel cell with a low-voltage distribution system is proposed in this paper.The traditional boost dc/dc converter plus voltage source inverter is replaced by a single-stage multilevel current-source inverter (MCSI).The MCSI can both interconnect to the grid and perform the maximum power point tracking algorithm. This novel single-stage converter approach provides active power to the grid, power factor compensation, and reduction of the line current harmonic content.The synchronization, modulation, and control scheme are implemented on a field-programmable gate array board using a fast-prototype high-level synthesis tool to reduce design time. Both simulation and experimental results show excellent behavior and fast dynamics while complying with IEEE and IEC harmonic content regulations.Fil: Cossutta, Pablo Martín. Instituto Tecnológico de Buenos Aires. Facultad de Ingeniería. Departamento de Electrónica. Centro de Investigación y Desarrollo en Electrónica Industrial; ArgentinaFil: Aguirre, Miguel Pablo. Instituto Tecnológico de Buenos Aires. Facultad de Ingeniería. Departamento de Electrónica. Centro de Investigación y Desarrollo en Electrónica Industrial; ArgentinaFil: Cao, Andres. Instituto Tecnológico de Buenos Aires. Facultad de Ingeniería. Departamento de Electrónica. Centro de Investigación y Desarrollo en Electrónica Industrial; ArgentinaFil: Raffo, Santiago. Instituto Tecnológico de Buenos Aires. Facultad de Ingeniería. Departamento de Electrónica. Centro de Investigación y Desarrollo en Electrónica Industrial; ArgentinaFil: Valla, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; Argentin