Study On Slot Modulation And Speed-regulation Performance Of Magnet Rotation-type Cage Axial-flux Magnetic Coupler

As a novel speed-adjustable transmission device,the magnet rotation-type magnetic coupler(MRMC)has several speed-regulation modes,the speed can be regulated by adjusting air-gap thickness or rotating unipolar magnet or adjusting both of them.Compared with the traditional speed-adjustable magnetic couplers,the MRMC has a larger speed-regulation range,and has significant energy-saving effect on centrifugal loads such as fans and pumps.In addition,the MRMC transmits torque without physics contact,thus,there is no friction and vibration during the operation,and the maintenance cost is low.The MRMC can be used for the transportation of dangerous media,and is widely applied in in chemical,coal,water conservancy,agriculture and other fields.Therefore,it has great significance to study the MRMC.In this dissertation,a magnet rotation-type cage axial-flux magnetic coupler(MRCAMC)is studied and main research work are as follows:(1)The magnetic equivalent circuit(MEC)model considering the induced magnetic field is proposed to derive the theoretical expressions of magnetic flux and electromagnetic torque of the MRCAMC when rotation angle is 0°,and speed-regulation models of the coupler under different loads are established.The induced flux generated by induced current is regarded as a leakage flux branch,and then is introduced into the MEC model.The expression of induced flux density is calculated by Ampere’s loop law.The modulation effect of the cogging iron in the conductor rotor on magnetic field by is considered by dividing the magnetic circuit.The main flux in the air gap of the coupler is divided into several branches,then the expressions of magnetic flux and electromagnetic torque is obtained by Kirchhoff’s law.Thus,the speed-regulation models under different loads are established according to the corresponding torque characteristics.(2)The electromagnetic field distribution,modulation effect of cogging and cogging torque characteristics of the MRCAMC are simulated and analyzed.The 3-D model of the coupler is established by using the finite element(FE)software.The static and transient magnetic field distributions under different air-gap thicknesses and different rotation angles of the unipolar magnet are simulated.The modulation effect of the cogging iron on the magnetic field and induced current under different air-gap thicknesses and different slip speeds are analyzed.It is found that the modulation effect of the cogging iron decreases with the increase of air-gap thickness and increases with the increase of slip speed.The cogging torque caused by the slots is simulated.The influence of the different working parameters and different structural parameters on the cogging torque are analyzed.It is found that with the increase of the air-gap thickness,the amplitude of cogging torque decreases.With the increase of the rotation angle of the unipolar magnet,the amplitude increases first and then decreases.With the increase of the slotting angle,the amplitude decreases first and then increases.With the increase of the slotting depth,the amplitude has no significant change.The cogging torque is weakened by optimizing the structural parameters.(3)The speed-regulation ranges of three speed-regulation modes under different loads are proposed,and energy consumption of three speed-regulation modes are compared and analyzed.The speed-regulation performance of the MRCAMC is simulated and analyzed.The mechanical characteristic curves of the coupler is obtained by FE simulation.Combined with the torque characteristic curves of the load,the speed-regulation performance under the constant torque load,quadratic rate load and constant power load are analyzed.The speed-regulation ranges of three speed-regulation modes under different loads are analyzed.It is found that with the increase of the torque value,torque coefficient and power value,the maximum speed-regulation ranges of the three speed-regulation modes increase first and then decrease.For the constant torque load and the constant power load,when the torque and power reach a certain value,the maximum speed-regulation range corresponding to different speed-regulation modes will be the same.For the quadratic rate load,the maximum speed-regulation range corresponding to composite speed-regulation mode is always larger than that of the other two speed-regulation modes.The energy-consumption of the three speed-regulation modes are simulated and analyzed.It is found that the energy-consumption of speed-regulation by adjusting air-gap thickness is the lowest when the range of speed-regulation is large,the energy-consumption by adjusting rotation angle is the lowest when the range of speed-regulation is small,and the energy-consumption by the composite speed-regulation mode is the lowest when the speed range is moderate.(4)A test platform is built to measure the transmission performance and speedregulation performance of the MRCAMC under three types of load condition.The mechanical characteristic curves of the coupler under different air-gap thicknesses and different slip speeds and the speed-regulation curves under types of load condition are obtained.The measured results are compared with the analytical results and simulation results.The results show that the measured results are in good agreement with the analytical results and simulation results in the case of small air-gap thickness and low slip speed.