In the induction electric energy transmission system applied to fix point charging of vehicles, the mutual inductance change caused by position deviation or air gap change, and the equivalent load change caused by power demand change will make the output power and efficiency fluctuate, thus affecting the output stability of the system. In order to ensure the reliability of the charging process of the system and at the same time have a strong power output capacity, this paper proposes a load segmental tracking control strategy based on the optimal power efficiency. This control strategy adjusts the equivalent load to track different power efficiency indicator curves according to different mutual inductance states of the system and power demand when the vehicle is static charging, so that it can always maintain the optimal power efficiency state according to different charging conditions and improve the system performance. Finally, simulation and experimental verification are carried out under different states of mutual inductance. The results show that this method can achieve the equivalent load segmental tracking under different mutual inductance states, and always maintain the optimal power efficiency output. INDEX TERMS Efficiency, inductive power transmission, load tracking, optimization, power.

The application of inductive power transmission system in trams makes trams get rid of the traditional overhead catenary, but the electromagnetic environment and safety problems brought by the inductive power transmission system also attract the public's attention. In this paper, the model of the wireless charging tram platform is built to analyze the electromagnetic environment when the tram stops at the platform. Then, the shielding shape of the platform is proposed. A mathematical model with the minimum shielding cost as the goal and the magnetic field and installation space as constraints, is proposed for the platform shielding model of wireless charging tram. The three-dimensional finite element simulation software is used to verify the designed platform shield. The results show that the designed platform shield can ensure the electromagnetic radiation at the platform reaches the standard, and the cost is low. The platform shielding scheme designed in this paper provides a theoretical basis for the establishment of electromagnetic protection measures in the practical application of the wireless charging tram.

The inductive power transmission system is applied to urban rail transit. Due to the limitations of the volume and coupling coefficient of the inductive coupling mechanism and the fact that the fluctuation of air gap in its movement will cause the fluctuation of mutual inductance value, DCDC booster link should be added to the side, rectifying side, to improve the output voltage level and stability. At present, most of the existing control strategies are based on the original side information communication. However, in the application of dynamic wireless charging in urban rail transit, the primary and secondary side coils are in the process of relative movement, so it is relatively difficult to establish reliable real-time communication, and it is easy to be interfered by electromagnetic transmission process, resulting in large errors. This paper analyzes the relationship between load and efficiency of IPT system applied to urban rail transit in detail and obtains the optimal load matching strategy of optimal efficiency. At the same time, an independent control strategy is proposed to eliminate the information communication of the primary and secondary sides and realize decoupling control. Finally, a simulation model is built to verify the effectiveness of the control strategy.

No abstract

As a new type of urban transit vehicle, Non-catenary trams using inductive power transmission technology get rid of the traditional overhead catenary. In engineering applications, coils assembled on the different tram bodies have inevitable differences due to the restrictions on the production process and other factors. Research shows tiny differences in self-inductance always lead to system detuning so as to causes an extreme descent of the system power factor. From the perspective of hardware design, the paper analyzes the system architecture and coil configuration for the dynamic charging trams with considering cost, system reliability, etc. Then, for the problem of power factor reduction caused by the differences in the self-inductance of the secondary windings, the article establishes a mathematical model with the maximum power factor as the goal and system parameters as constraints. And a complete system parameters design method is proposed. Finally, the global design and optimization of tram's electromagnetic coupling mechanism parameters are performed using the group method. The simulation result indicates that the method can meet the requirements of system operation and has a higher tolerance to the self-inductance differences of the secondary coils.