基于磁谐振式无线输能系统频率调谐的效率优化

Efficiency improvement of magnetic resonant wireless power transmission system based on frequency tuning

磁耦合谐振式无线输能系统理论设计上可在临界耦合的一段区间内达到高效率能量传输,但还存在远距离弱耦合区效率急剧衰减,近距离强耦合区出现谐振频率分裂现象的问题。为此,仿真并设计制作附有铁氧体磁芯的平面螺旋耦合线圈,在传输系统中做频率跟踪调谐,使传输距离在强耦合区变化时,依旧保持系统高效率传输。测试表明,整个系统可实现传输距离在5~20 cm变化时,都能保证无线输能效率高于80%。

Theoretically,the magnetic coupling resonance wireless power transmission system can be designed to achieve high efficiency within the critical coupling zone.However,the system efficiency will decrease sharply when the distance is in the weak coupling zone and the resonance frequency will split when the distance is in the strong coupling zone.Therefore,a planar spiral coupling coil with ferrite core is designed and fabricated.Then the frequency tuning system is designed to keep the high transmission efficiency even when the transmission distance changes in the strong coupling zone.Measurement results demonstrate,when the transmission distance changes between 5-20 cm,the designed wireless power transmission system can guarantee an efficiency above 80%.