Francisco Everton Uchoa Reis

This paper presents the extension of the Lyapunov-Metzler inequality for linear parameter-variating (LPV) switched systems. The proposed methodology is applied in the control of an approximate Van der Pol chaotic system via LPV synthesis. Numerical simulations are performed in the presented extension in order to analyze the behavior of the system both in open and closed loop. In the simulations carried out, the responses in time with varying parameters for the closed-loop stability and stabilization scenario were verified. From the above, it was possible to verify that the Van der Pol system obtained stability both in open loop and in closed loop for the proposed approach, which confirms the viability of this study in chaotic LPV switched models.

Electric vehicles (EVs) powered by batteries and other energy storage devices (ESDs), e.g., ultracapacitors, are expected to play an important role in the development of a more sustainable future. In this context, charging stations (CSs) are supposed to become the main sources of energy for charging the batteries, being strongly dependent on power electronic converters. This paper analyzes a bidirectional single-phase, three-level stacked neutral-point-clamped (3L-SNPC) converter for CS applications, which may behave as a rectifier or an inverter depending on the power flow direction. Besides, the derived analysis can be easily extended to the development of a three-phase version. Considering that the CS is capable of integrating the utility grid and renewable energy sources, it is possible to absorb or inject energy into the ac grid with high power factor and reduced harmonic content of the current. The main advantages of the bidirectional topology are the existence of a three-level voltage waveform across each leg and the neutral point, while filtering requirements are reduced when compared with typical two-level structures used in EV CSs; the voltage stresses on all semiconductors are equal to half of the total dc-link voltage; power factor is nearly unity in any operation mode; and the voltages across the dc-link capacitors are balanced. The thorough design of the power and control stages is presented, as well as experimental results from a laboratory prototype are discussed in detail.

This paper presents the linear quadratic regulator (LQR) control technique applied to a high gain boost converter based on three-state switching cell (TSSC). In order to control the state variables of the aforementioned converter, which usually are the current through the filter inductor and voltage across the output capacitor, the small signal average state-space model is used, as the mathematical equations are obtained. Due to the complexity of the converter, the physical circuit formed by semiconductors, magnetic elements, capacitors, and resistors, is initially transformed into an equivalent classical boost converter, and then the matrix equations that reproduce the converter's dynamic behavior are determined. After the modeling, with the aim to obtain the optimal control law that minimizes the predefined cost function, the compensator design is performed using MATLAB. The converter control system is validated through simulation using ORCAD and experimentation by developing a 1-kW laboratory prototype.