Search

Aiming at the problems of complex structure, fault prone and low accuracy of fault identification of asynchronous motor, this paper proposed a fault location recognition model of asynchronous motor based on AB-CNN (AdaBelief-CNN) intelligent algorithm. Taking asynchronous motor as the application background, an experimental platform is built to collect different types of fault data of asynchronous motor. Firstly, the dimension of the data is reduced by principal component analysis, the convolutional neural network (CNN) is used to carry out forward propagation fault recognition training for asynchronous motor fault data, and output the trained data prediction value. Secondly, through the loss function and AdaBelief optimization algorithm, the asynchronous motor fault location recognition model is optimized. Finally, the accuracy of the fault location identification model is tested with the test data. Comparing with the original CNN network identification model and Adam optimized CNN network (AD-CNN), the proposed solution outperforms other schemes by about 10%.

In this paper, a five-dimensional hyperchaotic system for secure communication based on MCU is proposed. First, a five-dimensional hyperchaotic system is constructed and the features such as equilibrium stability and Lyapunov exponents are analyzed. The states of this system with different parameters are studied, including periodic, hyperchaotic and chaotic state. Next, the complexity of system is analyzed. By analyzing the complexity of each dimension, the correctness of system selection is verified and the dimension with the highest complexity is selected for communication encryption. Then, the hardware circuit is designed. The encryption and decryption of square wave signal are completed through simulation which realizing the secure communication. Finally, the accuracy of system and the algorithm of realizing chaos of MCU are adjusted, and the system after adjustment is in a chaotic state verified by 0–1 test, the chaos is successfully generated by MCU. Using MCU can reduce the hardware cost of signal encryption greatly, and apply five-dimensional hyperchaotic system to secure communication can not only improve the security but also enhance the anti-interference ability in the process of signal transmission.

Compared with the static cipher, the dynamic cipher has the characteristic of "one cipher at a time" proposed by Shannon theory. Therefore, it is regarded as the safest among many forms of identity authentication. This paper proposes a five-dimensional chaotic system suitable for the construction of dynamic cipher and analyzes its relevant characteristics, including stability, balance, time-domain waveform, Poincare cross sectional diagram, Lyapunov exponent and bifurcation diagram. The results show that the chaotic system has multiple controllable parameters and a wide range of chaos, which is very suitable for constructing chaotic dynamic ciphers. The complexity of the proposed chaotic system is analyzed to verify the high security of the proposed system. On this basis, a dynamic cipher electronic lock based on chaotic system is designed in this paper. In the designed hardware circuit, the fourth order Runge–Kutta solving algorithm is used to discretize the constructed system, and the chaos is successfully implemented in the single-chip microcomputer. The phase diagram obtained from the circuit simulation data is basically consistent with the numerical simulation. Finally, the circuits of the handheld terminal and the electronic lock terminal are designed and simulated. The simulation results show that the preset function can be basically realized, and the generated chaotic dynamic cipher is random and irregular. The five-dimensional chaotic system proposed in this paper has complex dynamic characteristics, which makes the dynamic cipher electronic lock based on the chaotic system extremely safe.

To detect the fault of the doubly-fed induction generator (DFIG), in this paper, a fault detection method of novel sliding mode observer is proposed, without a velocity sensor. In addition to better elimination of chattering for the new sliding mode observer, at the same time, it has better stability and faster convergence speed than the traditional sliding mode observer. Firstly, the sliding mode observer is built according to the mathematical model of the DFIG. Then, the rotor current and the rotational speed are estimated. After comparing the actual rotor current value with the observed value, the self-detection of the fault for the DFIG is realized. Secondly, three faults of grid voltage sags failure, DFIG inter-turn stator fault and rotor current sensor fault are given respectively. After that the Simulink simulation model is built under different fault conditions. It is proved by simulation that this sliding mode observer can well detect faults occurring at different positions. Additionally, it can also be proved that the sliding mode observer has the characteristics of fast response and good stability.

Recently, Narrow- Band- Internet-of- Things are developing and being utilized in all industrial fields for the purpose of data transmission and equipment monitoring. Due to the existence of middleware such as firewalls, the TCP connection may be accidentally disconnected without a two-way heartbeat package. That means the TCP connection will not be completely disconnected. In this paper, we have improved the traditional heartbeat packet sending algorithm by using an exponential linear algorithm, and we can set the heartbeat rate within a reasonable intervals, which can reduce resource consumption as much as possible.