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This study deals with the transistor open-circuit fault diagnosis technique based on the grid current processing. In accordance with the proposed method, in the first stage, the defect of the power electronics converter is recognised. For this purpose, the zero current periods are registered in each converter phase circuits. The faulty transistors are identified calculating the average values of differences between predicted and measured phase currents. The novelty of the presented technique is an application of a neural network for the grid current prediction in the active rectifier. In fact, the transistor open-circuit faults do not affect the predicted grid currents immediately as soon as the transistor defects happen. Therefore, the differences between the predicted currents and the measured ones increase which are used for the faulty transistors identification. In the comparison to the switch open-circuit fault diagnostic techniques, which are known from the scientific literature survey, the method presented in this study is insensitive to load changes no matter a direction of the energy flow in the power conversion system.

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This paper presents issues related to the adaptive control of the drive system with an elastic clutch connecting the main motor and the load machine. Firstly, the problems and the main algorithms often implemented for the mentioned object are analyzed. Then, the control concept based on the RNN (recurrent neural network) for the drive system with the flexible coupling is thoroughly described. For this purpose, an adaptive model inspired by the Elman model is selected, which is related to internal feedback in the neural network. The indicated feature improves the processing of dynamic signals. During the design process, for the selection of constant coefficients of the controller, the PSO (particle swarm optimizer) is applied. Moreover, in order to obtain better dynamic properties and improve work in real conditions, one model based on the ADALINE (adaptive linear neuron) is introduced into the structure. Details of the algorithm used for the weights’ adaptation are presented (including stability analysis) to perform the shaft torque signal filtering. The effectiveness of the proposed approach is examined through simulation and experimental studies.

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The state feedback controller is increasingly applied in electrical drive systems due to robustness and good disturbance compensation, however its main drawback is related to complex and time consuming tuning process. It is particularly troublesome for designer, if the plant is compound, nonlinear elements are taken into account, measurement noise is considered, etc. In this paper the application of nature-inspired optimization algorithm to automatic tuning of state feedback speed controller (SFC) for two-mass system (TMS) is proposed. In order to obtain optimal coefficients of SFC, the Artificial Bee Colony algorithm (ABC) is used. The objective function is described and discussed in details. Comparison with analytical tuning method of SFC is also included. Additionally, the stability analysis for the control system, optimized using the ABC algorithm, is presented. Synthesis procedure of the controller is utilized in Matlab/Simulink from MathWorks. Next, obtained coefficients of the controller are examined on the laboratory stand, also with variable moment of inertia values, to indicate robustness of the controller with optimal coefficients.

Abstract. This paper deals with the application of the Radial Basis Function (RBF) networks for the induction motor fault detection. The rotor faults are analysed and fault symptoms are described. Next the main stages of the design methodology of the RBF-based neural detectors are described. These networks are trained and tested using measurement data of the stator current (MCSA). The efficiency of developed RBF-NN detectors is evaluated. Furthermore, influence of neural networks complexity and parameters of the RBF activation function on the quality of data classification is shown. The presented neural detectors are tested with measurement data obtained in the laboratory setup containing the converter-fed induction motor (IM) and changeable rotors with a different degree of damages.