In this paper, a simple method based on Field-Oriented Control (FOC) algorithm is proposed for Fault-Tolerant Control (FTC) of star-connected 3-phase Induction Motor (IM) drives for the Electric Vehicle (EV) applications. The proposed method is able to control 3-phase IM drive under both normal and stator winding open-phase fault conditions. The proposed FTC system is derived from a conventional FOC and requires only minor changes in parameters of the machine. The simulation results show that performance of the proposed control system is satisfactory in the case of 3-phase IM drive under open-phase fault. پرونده مقاله

In this paper, a hybrid system based on wind turbines, solar arrays and fuel cells is designed optimally in the view of economical and technical aspects. The objective of the hybrid system optimization is to minimize the system net peresent cost(NPC) while considering the reliability as a constraint. The economical designing aspect is defined as equivalent loss factor (ELF) of reliability. The NPC consist of capital, operation and maintenance, replacement and, especially, loss of load costs. The data of load, solar radiation and definitive wind speed are from the North West of Iran. It is assumed that between the system components, i.e., wind turbine, photovoltaic array and inverter, there is a forced outage probability. The cuckoo optimization (COA) and firefly algorithms(FA) are applied to optimize the hybrid system components and the results are compared with the last studies. The results show that the COA method is superior to the FA and the last studies, with respect to the economical and technical aspects and convergence speed. They also show that complete consideration of the components availability and the availability of inverter increases the generation costs of the system, but improves the system reliability indices, too. پرونده مقاله

In this study, single-phase current sensor Fault-Tolerant Control (FTC) for Three-Phase Induction Motor (TPIM) drives using a flux observer is proposed. In the proposed FTC scheme, a 3rd difference operator executes the Fault Detection (FD) task and the reconstruction of the faulted current is achieved through a flux observer. The presented FTC system is able to switch TPIM drive systems from normal mode to the faulty mode suitably. The proposed method in this study can be utilized in many industries particularly in electric vehicles, medical devices, and aerospace where TPIM drive systems are needed to continue the desired operation even during fault situations. The effectiveness of the proposed FTC system is confirmed by experiments on a 0.75kW TPIM drive platform. پرونده مقاله

This research investigates a simple method for Direct Rotor Field-Oriented Control (DRFOC) of star-connected 3-Phase Induction Motor (3Ph IM) drives under Single-Phase Open Fault (SPOF). The proposed control scheme includes a modified RFOC strategy in cooperation with a flux linkage observer. Most studies on this topic are intended for Indirect Rotor Field-Oriented Control (IRFOC), and hence are not appropriate at low speed operation due to using a pure integration for the flux angle calculation. To this end, a rotor flux linkage observer is designed which alleviates the speed and torque ripples of the faulty motor during low speed operation. The observer is capable of estimation of the rotor flux during healthy and SPOF conditions by only some modifications in the 3Ph IM parameters. The proposed DRFOC approach is tested under different conditions and the effectiveness of the proposed system is confirmed by experimental results. The results show the good fault tolerant capability and tracking performance of the proposed controller during different speeds. پرونده مقاله

Incorporation of nanoparticles into transformer oils improves their electrical and insulating properties. However, thermal aging may undesirably decrease the performance of nanomaterials in transformer oils. Herein, pure oil together with TiO2, ZnO, and CNTs incorporated oil (nanofluids) can underwent thermal aging by simulating this phenomenon at 110, 120, and 130 ° C for 30, 30, and 15 days (equivalent of 10, 30, and more than 40 years of normal oil operation, respectively). During the accelerated thermal aging process, the total acid number (TAN), breakdown voltage, and lightning impulse breakdown voltage of all samples were measured periodically. The TAN increased with increasing temperature and time, but never exceeded the allowable level of 1.2 mg KOH/g. As the oil ages, its corrosion rate increases, which is undesirable for the transformer. The results of the breakdown voltage test suggest that the TiO2 was the best candidate, such that the breakdown voltage increased with respect to the pure oil by 17, 27, and 48% at 110, 120, and 130 °C, respectively. The outcome of the lightning breakdown test also indicated that TiO2 still performed better than the other samples. TiO2 was able to improve the lightning voltage at 110, 120, and 130 °C by 33, 8, and 5%, respectively. Therefore, as it was observed, TiO2 has been able to perform the best performance in thermal aging. پرونده مقاله