Research Outputs
Study of intuitionistic fuzzy super matrices and its application in decision making
This work deals with the study of the open-source Arduino DUE board as a digital control platform for three-phase two-level Voltage-Source Converters (VSC) and Current-Source Converters (CSC), including (i) the description of the power topologies, its connection to the load or the ac grid, and the electrical signals required for sensors and power valves, (ii) the description of the Arduino Due board, its features, and its connection with the sensors and power valves in the converter, and (iii) evaluation of the Arduino DUE’s processing time required for typical power converter algorithms, such as modulation, mathematical transforms, and linear controllers typically used in these converters. Experimental results are presented to validate the study, showing that the Arduino DUE is a feasible digital control platform for this type of power converter.
FCS–MPC with nonlinear control applied to a multicell AFE rectifier
The use of controlled power converters has been extended for high power applications, stacking off-the-shelve semiconductors, and allowing the implementation of, among others, AC drives for medium voltages of 2.3 kV to 13.8 kV. For AC drives based on power cells assembled with three-phase diode rectifiers and cascaded H-bridge inverters, a sophisticated input multipulse transformer is required to reduce the grid voltage, provide isolation among the power cells, and compensate for low-frequency current harmonics generated by the diode-based rectifiers. However, this input multipulse transformer is bulky, heavy, and expensive and must be designed according to the number of power cells, not allowing total modularity of the AC drives based on cascade H-bridges. This study proposes and evaluates a control strategy based on a finite control set-model predictive control that emulates the harmonic cancellation performed by an input multipulse transformer in a cascade H-bridge topology. Hence, the proposed method requires conventional input transformers and replaces the three-phase diode rectifiers. As a result, greater modularity than the conventional multicell converter and improved AC overall input current with a THD as low as 2% with a unitary displacement power factor are achieved. In this case, each power cell manages its own DC voltage using a nonlinear control strategy, ensuring stable system operation for passive and regenerative loads. The experimental tests demonstrated the correct performance of the proposed scheme.
An efficiency analysis of 27 level single-phase asymmetric inverter without regeneration
For medium voltage applications, multilevel inverters are used. One of its classic topologies is the Cascaded H-Bridge, which requires isolated DC voltages to work. Depending on the DC voltage ratio used in the Cascaded H-bridge can be classified into symmetric and asymmetric. In comparison between symmetric and asymmetric inverters, the latter can generate an AC output voltage with more output voltage levels. DC voltage ratio most documented are binary and trinary. The last can generate an AC voltage of 3n = 27 levels is obtained, using n = 3 inverters in cascade and NLM modulation, which generates a flow power of the load to the inverters (regeneration). This work analyzes the semiconductor losses (switching and conduction) and the THD of the AC output voltage in function of index modulation, considering a non-regenerative modulation technique for a 27-level single-phase asymmetric inverter. To confirm the theoretical analyzes, simulation and experimental results are shown.
Finite control set—model predictive control with non-spread spectrum and reduced switching frequency applied to multi-cell rectifiers
Multi-cell converters are widely used in medium-voltage AC drives. This equipment is based on power cells that operate with low-voltage-rating semiconductors and require an input multipulse transformer. This transformer cancels the low-frequency current harmonics generated by the three-phase diode-based rectifier. Unfortunately, this transformer is bulky, heavy, expensive, and does not extend the existing power cell (three-phase rectifier—Direct Current (DC) voltage-link—single-phase inverter) to the transformer. In this study, a harmonic cancelation method based on finite control set-model predictive control (FCS–MPC), extending the power cell’s modularity to the input transformer. On the other hand, it considers treating the two disadvantages of the FCS–MPC: High switching frequency and spread spectrum. The details were developed in theory and practice to obtain satisfactory experimental results.