Circuit Model Of Solar Cell Research Articles

Lead-free tin perovskite solar cells

Summary The development of efficient and stable lead-free perovskite solar cells (PSCs) is crucial for addressing the concern of environmental pollution from the toxic element lead. In recent years, tin PSCs have emerged as a promising candidate for high-performance, eco-friendly photovoltaic technology with a high certified power conversion efficiency (PCE) of more than 11%, indicating a great potential for future applications. Here, we review the recent efficiency progress of tin PSCs based on the equivalent circuit model of solar cells. We then discuss approaches toward efficiency improvement from the device viewpoint, such as optimizing the band gap, increasing the light-harvesting efficiency and carrier diffusion length, surface passivation, and regulating the interface energy-level alignment. Finally, we point out the possibility of reaching 20% PCE for tin PSCs and issues regarding enlarging the cell size and realizing scalable production in the future. We expect that these perspectives will be helpful for accelerating the commercialization of tin PSCs.

Optimal Design of Photovoltaic MPPT Disturbance Step Length in a Rapidly Changing Environment

The traditional maximum power point tracking (MPPT) algorithm can not track the maximum power point (MPP) quickly and accurately in the environment of rapidly changing illumination amplitude. In this paper, based on the basic circuit model of solar cell, the small signal model between the disturbance step size of MPPT algorithm near the maximum power point and the intensity of light irradiance, ambient temperature, working voltage and working current is used, and then the MPPT duty cycle disturbance is modelled and analysed. The simulation results show that the model proposed in this paper clarifies the mechanism of the disturbance step size of MPPT algorithm in the environment of rapidly changing illumination amplitude. It also provides a theoretical basis for the design of subsequent disturbance step size.

Simulation of solar cells by delocalized recombination model and its applications

For lattice-mismatch, high-defect-density solar cells, the current-voltage curve is not perfects, and it always has high ideality factor and low shunt resistance. In traditional one-dimension circuit model of solar cells, there is a paralleled resistor Rp and recombination diodes with high ideality factor to simulate this imperfection. In this research, a delocalized recombination model is built based on the assumption that recombination could occur between trapped electrons from n type sides and trapped holes from p type side. The model with different parameters (i.e. defect volume w and recombination parameter Cp) is then added into current continuity equations and I-V curves of solar cells were calculated. With the increase of Cp, fill factor (FF) decreases obviously, followed by the decrease of short-circuit current and open-circuit voltage. Larger defect volume w would cause higher ideality factor. The effects of mobility on I-V curves were also calculated, low mobility leads to decrease of shunt resistance and fill factor. Two type of solar cells with different configurations were irradiated by 70 keV and the I-V curves show different degradation behaviors. Type A cell shows large decrease of shunt resistance indicating loss of mobility while type B cell shows increase of n(V) due to delocalized recombination. The difference is related to different thicknesses of GaInP.

Design of Schottky Contacts for Optimum Performance of Thin-Film Silicon Solar Cells

A full-scale model combining TCAD simulations with circuit modeling of p-type window layers in thin-film silicon solar cells is validated by experiment. The results demonstrate that Schottky contacts with a barrier height greater than 0.5 eV cause a kink in the simulated J-V characteristics that represents a considerable reduction of the open-circuit voltage when thermionic emission is the dominant transport mechanism. An optimum cell can be designed by facilitating tunneling mechanism through the Schottky barrier via an adjustment of the doping concentration of the semiconductor or by introducing thin μc-Si:H(p) in order to lower the barrier height between ZnO and a-Si:H(p). In such a case, however, the narrower bandgap of μc-Si:H compared with that of a-Si:H, and the misalignment of the energy bands between μc-Si:H(p) and a-Si:H(i), also compromise the short-circuit current and open-circuit voltage of the cell, respectively. Optimum interfaces for our 15-nm window layer are found when a combined μc-Si:H(p)/a-Si:H(p) with a 4/11-nm thickness ratio is used. A general circuit model for solar cells that accounts for the effects of nonohmic contacts is demonstrated. The ideality factor “n2 ” of the Schottky junction of the contact indicates the transport mechanism at the interface with values less than 0.5 eV having no impact on the cell performance.

Modeling method research of flexible amorphous silicon solar cell

Circuit model of solarcell is the core section of photovoltaic power generation system simulation model. The modeling methods of flexible amorphous silicon solar cell were studied based on improved photovoltaic cell circuit model. A group of flexible amorphous silicon solar cell’ I–V and P–V data were testedunder the condition of standard solar light. After that, Quasi-Newton method and self-organizing migrating algorithm (SOMA) were adopted to calculate the 8 unknown parameters of circuit model, finally establishing the single diode circuit model of this kind of amorphous silicon thin film solar cell. The optimal results calculated by-self-organizing migrating algorithm showed that the standard deviation of the calculated current in the circuit model is less than 0.79%, while the sum of squared residuals is only 0.05%. The model laid a theoretical foundation of performance optimization and maximum power tracking control technology development of flexible amorphous silicon solar cells.

Modelling of solar cells and modules using piecewise linear parallel branches

This study proposes a novel equivalent circuit model for solar cells and modules. The proposed model approximates the non-linear I–V characteristic of a photovoltaic cell or module by a number of linear circuit branches connected in parallel. The number of these linear circuit branches is adjustable according to the required accuracy. An algorithm based on an equal-area criterion for determining the parameters of the equivalent circuit is also proposed. This algorithm, if incorporated into the software that simulates the proposed model, allows variations of solar irradiance and cell temperature to be taken into account during the simulation. Two numerical examples simulated by electromagnetic transient programme software are presented to demonstrate the performance of the model.

독립형 태양광시스템에 적용한 태양광 모듈 시뮬레이션에 관한 연구

This presents the equivalent circuit model of solar cell with irradiation and temperature condition. Based on solar cell model, the photovoltaic module specification of manufacturer compare with photovoltaic module simulation and is investigated by simulation results. The obtained results indicate that residual of simulation value and specification value about photovoltaic module is lower. There is considerable validity in simulation of photovoltaic module. Thus, the optimum simulation of photovoltaic module array are studied in this paper. This paper propose the sizing optimization of photovoltaic module array for stand-alone photovoltaic system. Also, the proposed stand-alone photovoltaic system is setting in special region(in seoul). This paper presents simulation characteristic of optimization output power in seoul.

Evaluation of solar cell parameters by nonlinear algorithms

A numerical procedure is described to calculate the parameters of the equivalent circuit of a solar cell, based on the application of algorithms to optimise nonlinear functions defining the difference between experimental characteristics and the theoretical model. The authors have obtained empirical data from dark I(V) characteristics. A study of the method to obtain the initial solution is also included. Results obtained for space solar cells and commercial cells (terrestrial use) are given. Modifications of the commonly used equivalent circuit model of solar cells are suggested.