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In this paper, a novel adaptive second-order sliding mode (2-SM) control approach, based on online zero-crossing detection, was proposed to solve the problems of the chattering and fixed control gain for buck converters with multi-disturbances. In modeling, the possible parameter perturbations and external disturbances of the converter system were contained. Instead of the traditional first-order sliding mode (1-SM), the twisting algorithm with 2-SM was adopted for the controller design, which could overcome the chattering problem and realize control continuity. Meanwhile, a novel adaptive mechanism was introduced to replace the conventional fixed control gain by time-varying control gain, the idea of which is to calculate the number of the zero-crossing points of the sliding surface online. As a result, the control magnitude of the improved controller could be reduced to a minimal admissible level, and the steady error of the output voltage could converge to the expected value. Furthermore, the robust stability of the converter system with multi-disturbances wads investigated. Comparative simulations and experiments validated the advantages of this paper as offering better robustness and control performance. [ABSTRACT FROM AUTHOR]

This paper presents a solution based on optimal PID coefficients including anti-wind up for buck converter presents using meta-heuristic algorithm and chaos theory. A hybrid algorithm is called chaotic based flower pollination algorithm is provided by combining flower pollination algorithm and chaos theory with different maps. Five different choatic maps are used in the aim of increasing the efficacy and efficiency of flower pollination algorithm. In order to adjust the parameters combined in the flower pollination algorithm, random number sequences from Henon, Logistic, Sine, Tent and Tinkerbell chaotic maps are used. The success of the developed algorithm is evaluated by solving 23 different benchmark problems which are very common in the literature. The results of comparative experiments show that henon chaotic map based flower pollination algorithm is sufficiently effective in solving these benchmark problems. Thus desinging optimal PID with anti-windup for buck converter, henon chaotic map based flower pollination algorithm is used. Also henon chaotic map based flower pollination algorithm has better performance than firelfy algorithm and whale optimization algorithm existing in literature. [ABSTRACT FROM AUTHOR]

In this paper, a new single-stage power factor correction (PFC) converter is presented. In the input stage of this structure, a buck converter is used to correct the power factor. So, the voltage stress of bulk capacitor reduced, and one of the main problems in the single stage PFC converters is solved. Moreover, by employing a compensator circuit, the input current dead angle which is the main drawback of the existing buck type PFCs is obviated, thus the total harmonic distortion is very low. In converters with buck PFC, input current dead angle results in high THD. In the proposed converter, using an inductor coupled with the main transformer, this problem is solved. A part of input power is transmitted directly to the output that helps to improve efficiency. The proposed converter is analyzed and the validity of the proposed solution is proven in the form of theoretical analysis, simulation and practical results. [ABSTRACT FROM AUTHOR]

A photovoltaic array simulator is designed based on a Buck DC converter with a fuzzy PID control algorithm to account for current feedback. The conventional PID controller cannot self-tune the parameters, therefore the new algorithm uses a fuzzy controller to solve the problem. The difference between the reference current and the real-time feedback current of the Buck converter and its rate of change are regarded as two input variables of the fuzzy controller. The fuzzy controller outputs the adjustment quantities, which are then used to adjust the PID parameters. Next, the duty cycle of the electronic power switch is adjusted by a closed-loop fuzzy PID algorithm to make the output current of the simulator work at the anticipated point of the photovoltaic array on the I-V characteristic curve and realize the simulation of photovoltaic characteristics. Results of the simulation and experiment indicate that the proposed fuzzy PID control simulator can not only accurately simulate the static output characteristics of a photovoltaic cell, but can also rapidly realize the dynamic characteristics when the load or the external environment changes. The approximate error was less than 3.6%, the overshoot was less than 3.5%, the ripple coefficient was less than 3%, and the tracking time was approximately 0.3s. The fuzzy PID control simulator can work well as PV array experiment equipment for the research and development of photovoltaic systems. [ABSTRACT FROM AUTHOR]