发布时间：2024-04-15
To promote energy conservation and emission reduction, decrease vehicle exhaust emissions, and prevent air pollution, electric vehicles (EVs) have become a new type of transportation widely promoted around the world. However, due to battery capacity limitations, electric vehicles have a short driving range, and charging issues have always been one of the main bottlenecks restricting their development.
With the development of wireless power transfer technology, static wireless charging technology for electric vehicles based on magnetic coupling has received increasing attention. Compared to traditional wired charging systems, wireless charging systems have no electrical connections and offer advantages such as convenience, low maintenance costs, waterproof and dustproof capabilities, and fully automatic charging processes.
A typical electric vehicle static wireless charging system structure is shown in Figure 1, including power electronic converters, primary side compensation networks, transmitting coils, receiving coils, secondary side compensation networks, high-frequency rectification and filtering circuits, and battery loads. In recent years, domestic and international scholars and research institutions have conducted extensive research on magnetic coupling-based static wireless charging technology for electric vehicles.
However, as research has deepened, there are still many key issues that need to be addressed, such as system anti-offset capability, environmental sensitivity, system structure optimization, and stability control. Currently, the research on static wireless charging technology for electric vehicles is in a stage of tackling difficult problems, and further improvement and application of existing theories, as well as innovation and breakthroughs in principles, are still needed.
Based on the research status of static wireless charging technology for electric vehicles at home and abroad, it can be seen that this technology has been relatively well studied in various aspects, but there are still many problems to be solved. The main issues are as follows:
(1) System Anti-Offset Capability
How to improve the system's anti-offset capability has always been a research hotspot in electric vehicle wireless charging technology. In practical applications, influenced by the user's parking position, the relative position of the primary and secondary coils may vary within a certain range, causing changes in the coupling coefficient. This requires the system to have strong anti-offset capability.
Currently, the system's anti-offset capability is mainly improved through the design of magnetic coupling mechanisms or system closed-loop control. However, these technical measures have limited improvement effects, and it is necessary to seek breakthroughs from a mechanism perspective. In recent years, wireless power transfer technology based on Parity-Time Symmetry (PTS) principles has been proposed, which can achieve constant output power and efficiency within a certain range regardless of the coupling coefficient. In addition, wireless power transfer technology based on fractional-order circuits has also demonstrated excellent characteristics. Applying these new wireless power transfer technologies to electric vehicle wireless charging is expected to further enhance the system's anti-offset capability.