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This paper presents a speed tracking control method based on the model predictive control (MPC) algorithm for the four-wheel independently actuated (FWIA) electric vehicle. In the upper level controller, a switching control law is designed to reduce the impact when the car from acceleration to deceleration or from deceleration to acceleration. To avoid high frequency oscillations in the speed control, acceleration increment input law is designed in the lower level controller. The lower level controller calculates the desired torque using Newton's second law. The validity of the proposed control algorithm is verified using the CarSim/Simulink simulation, and the simulation results of the proposed method under extreme conditions are compared with PI controller, which shows the superiority of the proposed method. Finally, by the vehicle test, the experimental results verify the effectiveness and robustness of the proposed control approach.

Performing line commutation at an appropriate distribution switch can better balance the inductive reactance between three-phase lines and reduce transmission line losses. However, due to the large number of distribution lines and the complex operating environment, the management of distribution line is very difficult, and after the commutation some distribution lines may be in negative sequence operation because of failing to plan reasonably and no checking phase sequence in time, that affect the normal operation of the feeder terminal unit(FTU). This paper first analyzes the FTU's working principle of the dual power supply, then studies the FTU's protection function configuration, and then obtains the influence of negative sequence operation of the line on the power supply and protection of the FTU. And then, according to the negative sequence operation characteristics of the line, this paper puts forward some suggestions, such as adding phase sequence alarm function, phase sequence adjusted by software, etc. Finally, combined with a negative sequence operation case in Shandong Province, it is verified that the negative sequence operation of the line can affect the operation of the FTU and the proposed method can effectively improve the distribution line management efficiency and the reliability of the FTU.

With the medium and low speed maglev train plays the role of commercial operation gradually, people put forward higher requirements for train safety reliability, which makes train security assessment even more prominent. Aiming at the characteristics of the maglev train equipments as well as the limitations of traditional security assessment, the establishment of a multi-state security assessment based on Bayesian network model has better diagnostic reasoning and causal reasoning ability. Finally, using the model to analysis the train traction system quantitatively, finding the weaknesses of the system and the relationship between the equipments to make rational maintenance decision. This will provide a basis to improve the reliability of train equipment and repair and maintenance work.