نشریه صنایع الکترونیک
سال نهم شماره 2 (پیاپی 34، تابستان 1397)

This paper presents a new power management and control strategy of a hybrid energy system including photovoltaic, fuel cell, battery and supercapacitor in a islanded microgrid, which provides both active and reactive power to support an local load. The photovoltaic unit is the primary energy resource, which to supply the maximum power produced to the load, utilization of maximum power point tracking (MPPT) technique. Battery and supercapacitor both are considered for their different power density to supply transient and steady load, respectively. To increase the reliability of the system, the fuel cell has been selected to keep the battery fully charged. All resources are connected to dc bus by different dc-dc converters, and then the hybrid system through voltage source inverter (VSI) connected to ac load. For managing the active and reactive power independently in hybrid system, the fuzzy-adaptive control scheme based on sliding mode control (SMC) with fractional-order has been presented. The fuzzy-adaptive part is applied to approximate both the equivalent and switching control term in the sliding mode controller.

In this paper, a two-dimensional DOA estimation method for multipath environments is proposed, in which there are simultaneous uncorrelated, partly correlated and coherent signals. The presence of coherent signals caused a loss of rank in the spatial covariance matrix, resulting in a sharp reduction in the precision of the estimates. Therefore, in a novel approach, first of all, the noncoherent signals, coherent groups and the noise subspace are separated with a good accuracy, according to statistical data of the eigenvalues of the covariance matrix and the use of k-medoids clustering. The DOAs of noncoherent signals are estimated separately using the proposed method, after determining the total number of sources, the number of noncoherent signals and the number of coherent groups. The DOAs of coherent signals are estimated in each group by constructing a virtual steering matrix, after determining the number of coherent signals in each coherence group by the MDL criterion. The proposed method does not require any primary information such as knowing the number of sources. The simulation results show that the proposed method is able to distinguish between the noncoherent and coherent signals, even in the cases of low SNRs and low snapshots. Also, in terms of detection accuracy and resolution of estimation, the proposed method shows improvement of over 1.2% and 43% respectively, compared to the conventional FBSS scheme.

In this paper, design and optical simulation of a new thermophotovoltaic system is presented. In the proposed system, a Ta photonic crystal structure is used as an emitter section, and an InAs planar photovoltaic cell is used as absorber section. Based on the numerical simulation results, when the temperature of the emitter section is set at 1650k, the wavelength corresponding to the peak power transmission is around 1.7 micrometer, and the internal quantum efficiency will be optimum. For the temperature of 1650k, the internal quantum efficiency and the short circuit current of 77% and 62.5 mA/cm2 are achieved, respectively. The FDTD numerical method and analytical method (using of Matlab software) are used for optical simulations. The simulation results show that the proposed thermophotovoltaic system which contains the InAs planar photovoltaic cell, has a good performance as other state of art material (GaSb, InGaAsSb and InGaAs) and could well be used in solid-state energy conversion systems.

The Growing number of diabetic patients and the diabetes’ related healthcare problems, persuaded researchers to peruse telemedicine to monitor this disease. Telemedicine increases access to health service, care continuation, early treatment, and access to medical information. Thus, in this paper, we present, a non-invasive blood sugar measurement sensor based on a mobile system in android platform. In this system, the designed sensor can measure non-invasive blood sugar based on impedance parameter. The acquired information is sent to the patient‘s mobile phone through Bluetooth. The data are stored and processed by mobile phone, and the patient’s blood sugar is shown onscreen. In addition, the system can send information via SMS or email to a physician and present alarm to patient or his/her family. Comparative analysis of our proposed system with a portable standard system indicates over of 80% accuracy of our system for measuring the blood sugar. The non-invasive and wireless nature of the introduced system makes this a suitable alternative to the invasive blood sugar measurement systems.

In this paper, we are introducing a bias-less THz pulsed emitter. The presented emitter consists of asymmetric Schottky contacts on Low Temperature Grown (LTG)-GaAs layer, inducing an internal electric field. By radiating a short Gaussian pulse with the wavelength of 800 nm, carriers are generated in the active area of the device. Sharp edge transitions in the incident laser pulse is responsible for generating high frequencies in the resulted current. The resulted time varying current generates the THz radiation toward the bottom of the device. Applying the proposed pulsed emitter can lead to high output THz powers, owing to reduced thermal issues and possible using of higher input laser power, comparing with continues wave THz emitters. Moreover, benefiting from short input laser pulses, high frequency output components can be generated, which results in enhanced output bandwidth. 2D finite element method simulations have been used for the presented results in this article.

In this paper, an improved algorithm for aerial mosaicing and enhancement of the quality of the resulting images, along with a sequence of images are presented. Using this algorithm, the processing time for high-resolution images is significantly reduced. In this algorithm, images are first categorized to individual windows. Then a corresponding probability degree is assigned to each window. Finally, with the probability rating assigned to each window, the duplicate process is avoided to select points. The results of this paper show that using the above algorithm, mosaics of high resolution images with better accuracy and speed than existing algorithms are performed.

Quantum systems theoretically have a high power in the field of processing and sending information. But their interactions with the outside world lead to the problem of their realization in the real world. Quantum block stabilizer codes have been designed to overcome this problem. Each quantum block code with specific characteristics is described as a binary matrix which is called a generator matrix. Although many studies have been performed on the properties of an error-correcting code with a given generator matrix, a general method has not still been provided for reaching to a generator matrix. In this paper, a method for producing a general generator matrix by using genetic algorithms is presented. Simulation results show the performance of the proposed algorithm.

Tracking a mobile target is one of the primary applications in Heterogeneous Wireless Sensor Networks (heterogeneous WSNs). On the one hand, tracking without complex processing as well as achieving a high degree of accuracy and energy efficient consumption are critical requirements for these applications in a network area. On the other hand, artificial intelligence method provides adaptive mechanisms that present intelligent behavior in complex and dynamic environments like WSNs. In this paper, artificial neural networks are deployed to estimate target location. For this purpose, suggested beacon signals are able to facilitate distances estimation by which the network area is learned. Moreover, by analyzing the most probable region predicted for the next target location, a tracking window is created and sensors are dynamically clustered. Afterwards, sensors turn to the required mode to both preventing energy consumption and performing appropriate actions. The simulation results demonstrate the effectiveness of the proposed method.