Research On The Application Of Harmonic Generation In The Electromagnetic Clutch Device Of In-wheel Electric Vehicle

In this paper,a set of harmonic-generating coils in rotor are designed,which will induce electromotive force by utilizing the magnetic field of relative motion to rotor in air gap.The problem of offering electrical power to the magnetic clutch in the rotor is well resolved by the techlonogy of harmonic generation.After boosted and rectified,the induced electromotive force will charge the battery in rotor,and the battery will provide power for the electromagnetic clutch and wireless device in rotor.This kind of harmonic generation in rotor solves the problem of power supply of the low power device in rotor.Comparing to power supply from dry battery,the problem of frequently changing battery is avoided;comparing to power supply from external circuit via slip ring,there is no need to use slip ring and brush.Thus,the power supply of rotor is more reliable.First,the possible energy sources of harmonic generation in rotor are analyzed theoretically,and the feasibility of harmonic generation is proved.Then,the research is divided into two parts.For the first part,tooth harmonic magnetic field excited by permanent magnet in rotor is analyzed,and the number of pole-pairs and the rotational speed of relative motion to rotor are discussed.For the second part,the magnetic field of relative motion to rotor excited by armature winding is analyzed,and fractional-groove-concentrated-winding permanent magnet synchronous motor with the 46-pole 51-slot in experiment platform is emphatically analyzed.For the motor,the number of pole-pairs and rotational speed of harmonic that is of relative motion to rotor are analyzed.The motor model is designed according to the actual size with the aid of finite element analysis software Ansoft.The number of turns and winding position of harmonic-generating coil is designed in the case of half speed half load.The harmonic-generating coil is wound in the rotor of the motor according to the designed winding method.The ratio of transformer is completed according to the amplitude of the electromotive force induced by harmonic-generating coil and load,and the charging circuit in the rear-end is designed.Finally,in the case of half speed half load,the feasibility of harmonic generation is verified.