摘要
Abstract
As the advent of the fourth industrial revolution develops all automated and connected systems in industries,automated guided vehicles(AGVs)have become essential technologies for factory production and logistics systems.Since the AGV should be automatically parked and charged in the charging station,wireless power transfer(WPT)technologies are inevitably used instead of plug-in-type power cables or conductive charging.Compared with electric vehicles,the navigation system of AGV adds new challenges to the application of WPT technology.Recent studies have paid less attention to this problem.This paper proposes a navigation and power supply integrated DAD coil.
This paper introduces the structure of DAD coils and analyzes the principle of the DAD coil navigation and power supply from the coil magnetic field perspective.Most magnetic lines of the DAD coil form an annular closed magnetic field in the air gap magnetic field area.The leakage magnetic field is small,the coupling coefficient between primary and secondary is high,and the coil efficiency is high.From the navigation perspective,under different offset directions,the mutual inductance of the two coils on the secondary side changes differently.Therefore,the offset direction can be judged according to the relative value of mutual inductance,and the offset value can be judged by the difference of mutual inductance.
Then,the DAD coil with an LCC-S compensation topology is modeled and analyzed,and the loop current equation is written.With the traditional compensation parameters,it is found that the value of the coil output voltage is related to the secondary coupling inductance.There are two disadvantages:(1)The load voltage changes with the load,which is not conducive to DCDC voltage modulation and voltage stability;(2)The way of characterizing the offset direction and offset value by the voltage output difference is disturbed by the load.Therefore,the compensation parameters are improved,making the output voltage of the two secondary coils only dependent on the input voltage of the coupling mechanism,mutual inductance between the primary and secondary sides,and resonant inductance Lr.In general,during the operation of the WPT system,Uin and Lr remain unchanged,U1 and U2 can fully characterize the changes of Mp1 and Mp2.The two secondary coils can be used as a whole,which is conducive to further analysis and optimization.
Finally,the navigation and power supply performance of the DAD coil is verified by experiments.The mutual inductance and self-inductance parameters are measured,verifying the correctness of the navigation principle.A 400 W wireless charging system was built.The coil output voltage,load voltage,and efficiency were measured in the range from-50 mm to+50 mm offset.It is proved that the offset direction can be judged by the relative value of the secondary output voltage,and the offset value can be judged by the voltage difference.Aiming at the misjudgment problem when x=0 caused by the coil winding difference,using the voltage change value to characterize the offset can achieve a better navigation effect.In the range from-50 mm to+50 mm,the DAD coil achieves 400 W stable power transmission,and the efficiency is between 73.55%and 77.80%.关键词
自动导引小车(AGV)/无线电能传输(WPT)/线圈/导航Key words
Automated guided vehicle(AGV)/wireless power transfer(WPT)/coil/navigation分类
信息技术与安全科学
