controller

Nowadays, solar arrays and wind energy are considered as many renewable energy sources. These sources can deliver their energy to the grid or directly to the consumer. In power electronics, multi-input converters are commonly used to convert the energy of renewable energy sources into the power required by the grid. In this article, a high-gain non-insulated three-port converter based on a quadratic boost converter has been proposed. This converter includes two power supplies with controllable currents. This improves the performance of the converter and reduces the ripple current of the input sources. In addition, the proposed converter has two operating modes and can work with one or two voltage sources. To design a high-gain multi-input converter, first the structure and performance of the proposed converter are thoroughly analyzed and evaluated Then, using MATLAB software, the stability of the proposed converter is checked and the output voltage and input currents are controlled independently using the decoupling network method. Then the main equations are calculated theoretically and its performance in different duty cycles is investigated. Finally, the simulation results for different modes show the correct operation of the converter and controller.

The use of the input low-pass filter causes instability in DC-DC converters. These instabilities occur because of the interaction between the filter and the converter. In this paper, a control method based on Lyapunov is proposed. This control method uses the exact system model without linearization. All state variables are controlled using an instantaneous model. A new state variable is defined to reduce the static output voltage error. No condition is necessary to implement the control strategy. The simulation and experimental results are presented to validate the proposed control method.

Unlike classical cryptography, where security is based on computational complexity, quantum cryptography has unconditional security, which is based on physical constraints. So far, the semi-quantum version of many of the problems of secure quantum communication protocols has been proposed. In this study, we examined semi-quantum protocols that allow users to access a secret message directly without distributing the key. An important factor used to analyze the performance of secure quantum direct communication protocols is efficiency. In this study, the proposed semi-quantum secure communication protocol against various quantum attacks has been investigated. In the proposed scheme for decoding the confidential message by the receiver, a sequence of single photons is required, which is first generated by the controller. The proposed protocol has a yield of 50%, which is higher than the previous protocol, which has a yield of 66.6%.

This paper presents a robust ∞_H controller design, based on a generalized dynamic observer for uncertain singular systems in the presence of disturbance. The controller guarantees that the closed loop system be admissible. The main advantage of this method is that the uncertainty can be found in the system, the input and the output matrices. Also the generalized dynamic observer is used to estimate the states of system. This type of observer increases the steady state accuracy because of the integral term, and because of the dynamic term, it has a higher estimation speed than proportional-integral observers. First, the necessary conditions for existence a generalized dynamic robust observer are presented and some coefficients matrices of the observer are computed so that the estimation error asymptotically converges to zero. Then, the robust ∞_H controller is designed using state feedback in order to guarantee that the closed loop system is admissible. The existence conditions of the observer and the controller are given simultaneously using suitable Lyapunov function. Moreover, existing inequalities are transformed into linear matrix inequalities (LMI) using a set of algebraic relations, and by solving these LMIs, the coefficients of the observer and the controller are obtained. Finally, by presenting an algorithm, the computational method will be expressed in a systematic way, and a numerical example demonstrates the efficacy of the proposed method.

Static Synchronous Compensator (STATCOM) is a FACTS device whose structure is based on a voltage source converter and is installed in parallel to control the voltage of the transmission line in the power system. In this paper, a flat adaptive control system for STATCOM output voltage control is simulated. By linearizing the nonlinear dynamics and changing the system state variables, the controller designs the rules of control input stability, and an adaptive rule is obtained for designing the controller coefficients with the least system error. In the simulation results, the adaptive controller is compared with the traditional PI controller.