Low-cost Virtual Instrument Research Articles

Light Induced Degradation Quantification by Monitoring the VOC Output of Silicon Solar Cell Using Low-Cost Real-Time Virtual Instrumentation

Silicon-based solar cells suffer from different types of light-induced efficiency losses (can cause up to 10% loss), known as light-induced degradation (LID). Impurities, such as boron, iron, and oxygen, are common at different concentrations in these solar cells. They form active recombination defects in boron-doped mono-crystalline (Cz-Si) and multi-crystalline (mc-Si) solar cells during illumination. For the solar industry, this will lead to serious financial loss, hence the importance of inspecting and controlling the LID level accurately. Seeking to minimize the human factor and the inaccuracy that comes with it, we have proposed in this research a low-cost virtual instrumentation solution to provide a new real-time instrumentation technique for solar cell characteristics such as open circuit voltage (VOC). The virtual data acquisition system (VDAS) design is based on a low-cost Arduino board associated with MATLAB/Simulink software. Moreover, this system can collect in real time the values of solar cell outputs under prolonged illumination and under different temperatures of the LID test. Further, kinetic modeling of the solar cell output VOC variation as a function of light soak duration; shows the predominance of one type metastable defect over the LID test of c-Si solar cells. Additionally, degradation mechanism in mc-Si solar cells involve more than one metastable defect and are more complexes due to the mc-Si substrate elaboration technique compared to c-Si substrate. Furthermore, the temperature dependence of the concentrations (NVoc) and the thermal activation energies of the defects have been extracted from the experimental VOC measurements obtained using the VDAS. Finally, the system minimizes the test period and errors for solar cell characterization compared to traditional approaches.

Low-cost virtual instrumentation of PV panel characteristics using Excel and Arduino in comparison with traditional instrumentation

This paper presents a low-cost solution of virtual instrumentation to provide a new technique for real-time instrumentation of the PV panel characteristics such as voltage, current and power. The system design is based on a low-cost Arduino acquisition board. The acquisition is made through a low-cost current and voltage sensors, and data are presented in Excel by using the PLX-DAQ data acquisition Excel Macro, which allows communication between the ATMega328 microcontroller of an Arduino UNO board and the computer by UART bus. Hence, the I–V and P–V characteristics, which processed under real-time conditions, can be obtained directly and plotted on an Excel spreadsheet without needing to reprogram the microcontroller. A comparison between this low-cost virtual instrumentation and the traditional instrumentation is drawn in this work. It is found that our solution presents several benefits compared to the traditional solution such as the data can be presented in graphical form in real time. Thus, several experimental tests to confirm the effectiveness of the developed virtual instrumentation system are presented in this study.

Chemical sensing by differential thermal analysis with a digitally controlled fiber optic interferometer

In this work the implementation of an optical fiber interferometric system for differential thermal analysis enabling the identification of chemical species is described. The system is based on a white light Mach-Zehnder configuration using pseudo-heterodyne demodulation to interrogate two identical fiber Bragg gratings (FBG) in a differential scheme. System performance is compared using either standard hardware or low cost virtual instrumentation for operation control and signal processing. The operation with the virtual system enabled temperature measurements with a ±0.023 °C resolution nearly matching the performance of the standard hardware. The system ability to discriminate chemical species by differential thermal analysis was demonstrated. Mixed samples of acetone and methanol could be successfully identified, indicating the suitability of the system for high precision measurements using low cost instrumentation.

Virtual Instrumentation Applied to Calculation of Electrical Power Quantities in Single-Phase Systems

This paper presents a low cost virtual instrumentation platform. It is used in single-phase systems in order to calculate electric power quantities and indicators defined in IEEE Std. 1459-2010. The algorithm used to calculate the power quantities and indicators are based on synchronous reference frame, which is used to implement the definitions presented in IEEE Std. 1459-2010 under sinusoidal and nonsinusoidal utility conditions. To confirm the theoretical development, experimental results are presented by means of a versatile power monitoring system using a graphic platform, in which the apparent, active and nonactive powers can be viewed and analyzed, as well as the indicators.

Power System Frequency Measurement Under Nonstationary Situations

A new method for the measurement of the instantaneous power-system frequency is proposed. It is based on the frequency estimation of the voltage signal using three equidistant samples. An algorithm is developed that diminishes the variance of the estimation. The procedure is applied to the case of single- and three-phase networks, and uncertainty in the frequency estimation is obtained with simulated signal and severe conditions of signal quality. A frequency variation has been assumed as plusmn2 Hz around the nominal value, with a maximum rate of change of 1 Hz/s. The uncertainty of 25 mHz and 3.5 mHz has been obtained for single- and three-phase signals, respectively. A low-cost virtual instrument has been developed to make frequency measurements over the actual voltage signal.

Low-cost virtual instrumentation system of an energy-dispersive X-ray spectrometer for a scanning electron microscope

Low-cost virtual instrumentation system of an energy-dispersive X-ray spectrometer for a scanning electron microscope

Low‐cost virtual instrumentation system of an energy‐dispersive X‐ray spectrometer for a scanning electron microscope

The paper describes an energy-dispersive X-ray spectrometer for a scanning electron microscope (SEM-EDXS). It was constructed using the new architecture of a virtual instrument (VI), which is low-cost, space-saving, fast and flexible way to develop the instrument. Computer-aided teaching (CAT) was used to develop the instrument and operation rather than a traditional instrument technique. The VI was designed using the object-oriented program language C++ and compact programmable logical devices (CPLD). These include spectra collection and processing, quantitative analysis and X-ray-intensity distribution analysis. The procedure is described in detail. The VI system gives an e¡ective and user-friendly human interface for the whole analytical task. Some examples are described.