Journal of Electrical and Computer Engineering
ISSN / EISSN : 2090-0147 / 2090-0155
Current Publisher: Hindawi Limited (10.1155)Former Publisher:
Total articles ≅ 785
Latest articles in this journal
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-12; doi:10.1155/2021/5515362
In the off-grid microgrid cluster, the energy storage device is mainly charged and discharged to maintain the stability of the bus voltage and the system power balance. Generally, the voltage and current double closed-loop control and fuzzy control are adopted for the energy storage converter. The traditional double closed-loop control parameters and the scale factor and quantization factor in fuzzy control cannot be adjusted in real time during system operation, resulting in slower dynamic response and weak anti-interference ability of the system. In response to the above problems, this paper proposes an adaptive genetic fuzzy double closed-loop control, which can adjust the PI control parameters in real time by adjusting the quantization factor and the scale factor to optimize the control effect. The simulation platform is built in MATLAB/Simulink and the simulation results show that the adaptive genetic fuzzy double closed-loop control combines the advantages of fuzzy and PI control. Under different working conditions, the system has not only a fast dynamic response, small overshoot, and strong anti-interference ability but also good robustness.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-9; doi:10.1155/2021/5557756
In heterogeneous wireless sensor networks, sensor nodes are randomly distributed in some regions. In some applications, they may be randomly distributed in different regions. Besides, nodes with the same type have almost the same probability to be selected as cluster head. The cluster head will consume much more energy to receive and transmit data than the other nodes. If nodes with little residual energy have been elected as cluster heads, it will affect the efficiency of the network due to its early death. An improved energy-efficient routing protocol is proposed for heterogeneous wireless sensor networks. Firstly, it supposes that the different types of nodes are distributed in different zones. Secondly, by improving the threshold, nodes with large residual energy have a greater possibility of becoming cluster heads. In the end, it designs a mixed data transmission method. The cluster heads of supper nodes and advance nodes directly transmit data to the base station. The normal nodes adopt single hops and multiple hops mixed methods to transmit data. This can minimize the energy of the communication from cluster head to base station. Simulation results show that this algorithm has achieved a longer lifetime for the wireless sensor network than stable election protocol and threshold-sensitive stable election protocol algorithm.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-10; doi:10.1155/2021/1654836
The interelement spacing of a coprime array breaks through the half-wavelength limitation, so that a larger array aperture can be obtained with a fixed number of array elements. In this paper, the symmetry of the noncircular signal is used to virtually expand the L-shaped array into an orthogonal cross array. Furthermore, the virtual received signal of the augmented array is obtained by the second-order statistic of the received data. Decoupling and dimension reduction of elevation and azimuth are realized by a z-axis subarray and y-axis subarray. Finally, the sparse reconstruction of the signal is realized by the minimum absolute convergence and selection operator method. This method can enlarge the aperture and freedom of array and has higher accuracy and resolution of DOA estimation. It has the advantages of automatic parameter pairing without additional pairing operation and is effective for coherent and incoherent signals. The final numerical simulation results prove the effectiveness of the method in this paper.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-11; doi:10.1155/2021/7146435
In this paper, the multilevel classification model of high-speed railway signal equipment fault based on text mining technology is proposed for the data of high-speed railway signal fault. An improved feature representation method of TF-IDF is proposed to extract the feature of fault text data of signal equipment. In the multilevel classification model, the single-layer classification model was designed based on stacking integrated learning idea; the recurrent neural network BiGRU and BiLSTM were used as primary learners, and the weight combination calculation method was designed for secondary learners, and k-fold cross verification was used to train the stacking model. The multitask cooperative voting decision tree was designed to correct the membership relationship of classification results of each layer. Ten years of signal switch machine fault data of high-speed railway are used for experimental analysis; the experiment shows that the multilevel classification model can effectively improve the classification of signal equipment fault multilevel classification task evaluation index and can ensure the correctness of the subordinate relations’ classification results.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-9; doi:10.1155/2021/9152035
Robot detection, recognition, positioning, and other applications require not only real-time video image information but also the distance from the target to the camera, that is, depth information. This paper proposes a method to automatically generate any monocular camera depth map based on RealSense camera data. By using this method, any current single-camera detection system can be upgraded online. Without changing the original system, the depth information of the original monocular camera can be obtained simply, and the transition from 2D detection to 3D detection can be realized. In order to verify the effectiveness of the proposed method, a hardware system was constructed using the Micro-vision RS-A14K-GC8 industrial camera and the Intel RealSense D415 depth camera, and the depth map fitting algorithm proposed in this paper was used to test the system. The results show that, except for a few depth-missing areas, the results of other areas with depth are still good, which can basically describe the distance difference between the target and the camera. In addition, in order to verify the scalability of the method, a new hardware system was constructed with different cameras, and images were collected in a complex farmland environment. The generated depth map was good, which could basically describe the distance difference between the target and the camera.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-9; doi:10.1155/2021/6692410
The world intention toward open data technology has increased in the past years, and governments started to explore open data technology in the public and private sectors and tried to check its advantages and disadvantages. However, in the Arab world and especially in Kuwait, there is no solid structured attention about the technology in both sectors. As a result, we tried in this paper to determine if business owners in Kuwait have enough knowledge of the open data (OD) concept and if they have the willingness to use it for enhancing their services. The purpose of this research is to measure the acceptance of OD technology in Kuwait and to gather business owners' opinions about the ability to adopt the OD concept. Making online and hardcopy survey was our method for gathering different reactions and points of view about this technology. We intended to focus on the private sector and we targeted people who own a business and wish to introduce better services for their customers. Overall, the results have shown clear features about open data technology in Kuwait and the substantial need of education and awareness of the importance of this technology. The results of this study may positively and directly affect the level of motivation for other existing studies.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-18; doi:10.1155/2021/5514674
Under the trend of high density and miniaturization, the current that the connector transmits per unit volume is getting higher and higher, which makes the reliability design of the connector more challenging. Under the pressure of high performance and low cost requirements, the design has to be more accurate and more efficient. Thus, in the design process, a systematic approach for reliability evaluation is required. However, there is no valid enough approach that is integrated, well-organized, and quantitative. In this article, a systematic approach for the reliability evaluation of connector was proposed, and by applying it on a typical object named a blade-spring connector, the validity of this approach was verified. After the framework of this approach has been established, the methods and models needed were provided, including the method to build up material selection criterion and the assessment models of stress relaxation, thermal diffusion, and sliding wear, respectively. Then, the feasibility of a newly developed copper alloy on the connector and the reliability behaviors of this connector were determined through this approach. The unsatisfactory aspects of reliability were pointed out and some possible redesign choices were provided. Results and discussion revealed that the proposed approach is a helpful tool for designing electric connectors, especially on the reliability design.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-11; doi:10.1155/2021/6665384
The concept introduced by MathWorks in the Simscape product is the link representation between the SIMSCAPE library components that correspond to physical connections transmitting power. In this paper, a power insulated-gate bipolar transistor (IGBT) model using MATLAB graphical software is reproduced. An electrical IGBT behavior model using the Simscape Electronics library components is developed and analyzed. This model is parameterized using the constructor datasheet to ensure a good representation of the dynamic and static IGBT behaviors. An extraction and optimization studies of the IGBT model parameters using a stochastic algorithm implemented in Matlab are presented. The proposed method is based on the Genetic Algorithm (GA) to perfectly extract and optimize the model parameters using the mathematical model circuit equations and the provided datasheet characteristics. A simulation in the Matlab/Simulink environment and a comparison with the experimental results for an IGBT device example are carried out to demonstrate the proposed model accuracy.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-7; doi:10.1155/2021/5579692
Resolvers are widely used in electric vehicles, trains, and other harsh fields because of their robustness. However, the resolver outputs two orthogonal analog signals, which make the resolver decoding either high hardware cost or poor decoding accuracy. A noise robust resolver decoding method using Hilbert transform and angle-tracking observer (ATO) is proposed in this paper. Firstly, Hilbert transform is employed to obtain the modular envelopes of resolver signals. Next, the modular envelopes are filtered, and their quadrants are recognized by the polarity relation of the resolver signals and the modular envelope extreme point. Then, the ideal demodulating signals are gained through the linearization of the envelope zero point. Finally, the improved ATO is used to obtain the rotor angle by iteratively calculating the demodulating signal. The effectiveness of the proposed method is verified by experiments under various rotor speed conditions and compared with other methods in noise immunity. The results show that the proposed method can control the decoding error within 0.5° when the SNR is 30 dB, which provides a high-precision and low-cost decoding scheme for practical applications.
Journal of Electrical and Computer Engineering, Volume 2021, pp 1-8; doi:10.1155/2021/5598180
In the matching pursuit algorithm of compressed sensing, the traditional reconstruction algorithm needs to know the signal sparsity. The sparsity adaptive matching pursuit (SAMP) algorithm can adaptively approach the signal sparsity when the sparsity is unknown. However, the SAMP algorithm starts from zero and iterates several times with a fixed step size to approximate the true sparsity, which increases the runtime. To increase the run speed, a sparsity preestimated adaptive matching pursuit (SPAMP) algorithm is proposed in this paper. Firstly, the sparsity preestimated strategy is used to estimate the sparsity, and then the signal is reconstructed by the SAMP algorithm with the preestimated sparsity as the iterative initial value. The method reconstructs the signal from the preestimated sparsity, which reduces the number of iterations and greatly speeds up the run efficiency.