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This study presents a mathematical model of a parabolic trough solar collector with photovoltaic cells integrated into its solar receiver. A case study is presented, utilizing meteorological data obtained from the localities of Cuernavaca and Mexicali in Mexico. The results demonstrate moderately variable electrical and thermal energy production for Cuernavaca (387.93 kWh to 239.38 kWh and 1036.11 kWh to 641.26 kWh, respectively). In contrast, the production of electrical and thermal energy in Mexicali exhibited considerably greater fluctuations (515.16 kWh to 177.69 kWh and 1424.39 kWh to 448.88 kWh, respectively). Furthermore, a parametric study is presented, which analyzes the impact of solar receiver geometry and mass flow on the model's behavior. The results demonstrate that the pipe length exerts the most significant influence on the electrical and thermal power output (1.21 kW to 2.22 kW and 3.7 kW to 6.9 kW, respectively). Additionally, the diameter has an impact on the thermal power output (5.23 kW to 7.1 kW) and the electrical and thermal efficiency (0.18 to 0.15 and 0.54 to 0.74, respectively). Modifying the mass flow facilitates the enhancement of electrical power and efficiency (1.54 kW to 1.72 kW and 0.16 to 0.18, respectively) while concurrently preventing a significant reduction in thermal power and efficiency (5.4 kW to 5.3 kW and 0.56 to 0.55, respectively). A script with the developed model is provided. [ABSTRACT FROM AUTHOR]

This paper is a summary of the last ten years of work on the study of parabolic trough collectors (PTCs) and compound parabolic collectors (CPCs) coupled to photovoltaic and thermal solar receiver collectors (SCR-PVTs). While reviewing the state of the art, numerous review papers were found that focused on conventional solar receiver collector (SRC) technology for solar thermal generation. However, there is a lack of review papers summarizing SRC-PVT hybrid technology for solar electric/thermal generation, which would be beneficial for researchers interested in this area of research. This paper provides a review of SRC-PVT hybrid technologies. The theoretical foundations for analyzing and modeling PTC and CPC concentrators coupled to SRC-PVT are described, with an emphasis on modeling through thermal resistances and energy balances. Additionally, this section provides a concise overview of previous studies that have addressed the modeling of PTC and CPC collectors coupled to SCR-PVT, as well as experimental information useful for the validation of new mathematical models of SRC-PVT. [ABSTRACT FROM AUTHOR]

Currently, the design of resonant power converters has only been developed while operating in the steady state, while the design operating in the transient stage has not been considered nor reported. This paper is interested in testing the performance of the resonant circuits operating in the transient stage and finding applications where benefits can be obtained from this form of operation. One application in which it is possible to obtain benefits from designing resonant circuits in the transient state is in the area of frequency multiplication. Usually, to achieve frequency multiplication, it is necessary to resort to complex methods and special devices that increase the complexity of the design and the total cost of the circuit. This paper evaluates the performance of a series RLC resonant circuit operating in the transient stage and with an underdamped response acting as a frequency multiplier, where the oscillation frequency of the current in the resonant tank is "n" number of times the switching frequency of the square voltage source at the input with a duty cycle of D = 50%. To validate the analysis, a circuit was designed to deliver an output power of 30 watts to a resistive load, where the switching frequency of the square voltage source at the input was 500 kHz. Since a multiplier value "n" equal to fifteen was chosen, the current in the resonant tank reached an oscillation frequency of 7.5 MHz. The design methodology was validated by simulations in SPICE, complying with the established design parameters. [ABSTRACT FROM AUTHOR]

This paper presents the design of a maximum power point-tracking (MPPT) technique for DC–DC converters that are used in energy-harvesting systems based on thermoelectric generators. This technique is based on the analysis of the characteristics of the converter to measure the open-circuit voltage indirectly. The main contribution of this article is that the algorithm measures the voltage at the maximum power point without the need to disconnect the source of the circuit, as happens when the fractional open-circuit voltage (FOCV) technique is used. The algorithm is based on a predetermined initial duty cycle, which is applied to the circuit, and the input voltage and input current are read. With these values, the open-circuit voltage and short-circuit current are calculated with equations obtained from the circuit. Then, it calculates the duty cycle at the maximum power point and applies it to the circuit. If this duty cycle does not obtain the maximum power from the circuit, the algorithm starts a second stage based on fuzzy logic to calculate an increase or decrease in the duty cycle. The designed technique was evaluated using a topology based on a DC–DC flyback converter variant and was compared with the P&O technique and obtained better results. The designed technique provides between 3.9% and 5.6% more power to the load than the P&O technique in a 20 W system. [ABSTRACT FROM AUTHOR]

Capacitive technology for wireless power transmission has been shown to be a good option for charging the batteries of electric vehicles. It offers better coupling between the transmitter and the receiver than inductive power transmission. On the other hand, it has some disadvantages; for example, it is very sensitive to the distance between plates. Several ideas have recently been proposed to overcome this disadvantage. However, a proper analysis methodology is still lacking, as is a proper design procedure for the circuits used in capacitive transmission. In this paper, an analysis and design methodology is presented for applying the Z-tank resonant circuit to capacitive power transmission, and the theoretical design methodology is based on normalized equations with respect to the operating resonance frequency. The analysis methodology and design procedure result in a circuit where the resonance frequency remains constant despite changes in the distance between the capacitive plates. The simulation results validate the proposal; to ensure robust, realistic simulation results, parasitic elements were considered in all reactive components, and robust models were built for the switching elements, such as MOSFETs and diodes. The results show that the multi-resonant characteristic of the circuit achieves maximum energy transfer and high efficiency. [ABSTRACT FROM AUTHOR]