Investigation of the Combination of ITO/CdS/CdTe/Cu/Au Solar Cells in Microassembly for Electrical Supply of Field Cables

Studies aimed at optimizing the design of micromodules based on ITO/CdS/CdTe/Cu/Au photoelectric converters, which are used in autonomous power plants for field camps, have been carried out. To use photoelectric converters as power sources, they are combined into micromodules and modules. The nature of commutation of single solar cells in the microassembly significantly affects the output characteristics of the micromodule and, consequently, the efficiency of the photoelectric converter as a whole.It is found that the series connection of the ITO/CdS/CdTe/Cu/Au PEC in the micromodule ensures its stability even if the output parameters of one or more single solar cells fail or deteriorate. If the composition of the micromodule includes a solar cell with significantly worse output characteristics, or there are several such elements, then when they are connected in series, the efficiency of the micromodule is several times higher than for a parallel cell. With the series connection of the ITO/CdS/CdTe/Cu/Au PEC in the micromodule composition, experimental samples of the micromodule with an efficiency of 5.3 % are obtained, which is almost 2 times higher than for parallel connection of the same PE

Development of a Technique for Restoring the Efficiency of Film ITO/CdS/CdTe/Cu/Au SCs After Degradation

A study into the influence of direct polarity on the output parameters of ITO/CdS/CdTe/Cu/Au solar cells (SC) has been conducted. We have experimentally registered the effect of an electric field of direct polarity on the output parameters and light diode characteristics of ITO/CdS/CdTe/Cu/Au SCs, which underwent a degradation of efficiency. When a shaded SE is exposed for not less than 120 minutes to the electric field, induced by an external DC voltage of magnitude (0.5‒0.9) V, whose polarity corresponds to the forward bias of n-p heterojunction, there is an increase in efficiency coefficient. This becomes possible if, during degradation of the instrument structure, such defects did not have time to develop, which, over the specified time of exposure, lead to resettable alternating electric microbreakdowns. It has been established that an increase in efficiency coefficient comes at the expense of the increased density of a photocurrent, decreased sequential and increased shunt resistances of SC. Improvement of diode characteristics occurs due to several physical processes. When a SC is fed a forward bias voltage, an electric field forms inside the diode structure of SC, which amplifies the built-in electric field of the rear р-р+ heterojunction and suppresses the built-in electric field of the frontal n+-p heterojunction. That occurs because the diodes are turned on towards each other. The magnitude of a forward bias voltage must not exceed the height of the potential barrier in a heterojunction. In this case, at the rear р-р+ heterojunction and in its adjoining areas from both sides the processes will be intensified that are associated with the transport of copper atoms, the restructuring of complexes of point defects containing copper, and the phase transformations of Cu1,4Te into Cu2-xTe. In addition, under the influence of the field induced by a forward bias voltage, the CuCd- particles from the depletion area of a CdS layer will start moving towards the absorber. That should reduce the resistance part of the CdS layer and lead to a decrease in the depletion area width from the absorber's side, thereby increasing the spectral sensitivity of SC in the shortwave and medium-wave fields of solar spectrum. Electrodiffusion of additional amount of CuCd- to the absorber must enhance the above-described and related effect of the increased spectral sensitivity and thus Jph of instruments. Based on the conducted research, we have constructed an algorithm for restoring the efficiency of ITO/CdS/CdTe/Cu/Au SCs and for rejecting the irrevocably degraded instrumental structures included in a running modul

Geometric Modeling of the Unfolding of a Rod Structure in the Form of a Double Spherical Pendulum in Weightlessness

We investigated the geometric model of the new technique for unfolding a rod structure, similar to the double spherical pendulum, in weightlessness. Displacements of elements occur due to the pulses from pyrotechnic jet engines acting on the endpoints of links. The motion of the obtained inertial unfolding of a rod structure was described using a Lagrange equation of the second kind. Given the conditions of weightlessness, it was built applying only the kinetic energy of the system.The relevance of the chosen subject is emphasized by the need to choose and study the process of activation of the unfolding of a spatial rod structure. The proposed possible drivers are the pulse pyrotechnic jet engines installed at endpoints of the structure's links. They are lighter and cheaper compared, for example, to electric motors or spring devices. In addition, they are more efficient economically when the process of unfolding a structure in orbit is planned to be performed only once.We propose a technique for determining the parameters and initial conditions for initiating the oscillations of a double rod structure in order to obtain a cyclic trajectory of the endpoint of the second link. That makes it possible to avoid, when calculating the process of transformation, the chaotic movements of the structure's elements. We built the time-dependent charts of change in the functions of generalized coordinates, as well as the first and second derivatives from these functions. Therefore, there is a possibility to estimate the force characteristics of the system at the moment of braking (locking) the process of unfolding.The results are intended for the geometric modeling of one of the variants for unfolding the large-sized structures under conditions of weightlessness, for example, force frames for solar mirrors or space antennas, as well as other large-scale orbital infrastructures

Development of a Method for Computer Simulation of a Swinging Spring Load Movement Path

Studies of geometric modeling of non-chaotic periodic paths of movement of loads attached to a variety of mathematical pendulums were continued. Pendulum oscillations in a vertical plane of a suspended weightless spring which maintains straightness of its axis were considered. In literature, this type of pendulum is called a swinging spring. The sought path of the load of the swinging spring was modeled with the help of a computer using values of the load weight, stiffness of the spring and its length without load. In addition, initial values of oscillation of the swinging spring were used: initial angle of deviation of the spring axis from the vertical, initial rate of change of this angle as well as initial parameter of the spring elongation and initial rate of elongation change. Calculations were performed using Lagrange equation of the second kind. Variants of finding conditionally periodic paths of movement of a point load attached to a swinging spring with a movable fixing point were considered.Relevance of the topic was determined by necessity of study and improvement of new technological schemes of mechanical devices which include springs, in particular, the study of conditions of detuning from chaotic oscillations of the elements of mechanical structures and determination of rational values of parameters to ensure periodic paths of their oscillation.A method for finding values of a set of parameters for providing a nonchaotic periodic path of a point load attached to a swinging spring was presented. The idea of this method was explained by the example of finding a periodic path of the second load of the double pendulum.Variants of calculations for obtaining periodic paths of load movement for the following set parameters were given:‒ length of the spring without load and its stiffness at an unknown value of the load weight;‒ length of the spring without load and the value of the load weight at unknown spring stiffness;‒ value of the load weight and stiffness of the spring at an unknown length of the spring without load.As an example, determination of the values of a set of parameters to provide a non-chaotic, conditionally periodic path of movement of a point load attached to a swinging spring with a movable attachment point was considered.Phase paths of functions of generalized coordinates (values of angles of deflection of the swinging spring axis from the vertical and extension of the spring) were constructed with the help of which it is possible to estimate ranges of these values and rates of their variation.The results can be used as a paradigm for studying nonlinear coupled systems as well as in calculating variants of mechanical devices where springs affect oscillation of their elements when it is necessary to detune from chaotic movements of loads in the technologies using mechanical devices and provide periodic paths of their movemen