Research On High Speed Permanent Magnet Synchronous Loading Generator

High speed motor has the characteristics of high power density,small volume,fast dynamic response and high efficiency.It has been widely applied in the industr y.The development of high speed motor towards higher speed and higher power puts forward higher requirements for loading test system.Due to those problesms brought by traditional test methods at high speed,a non-contact electromagnetic loading method based on electromagnetic torque of generators is proposed.As a loading equipment,the performance of the generator directly affects the effect of loading.Therefore,this paper takes the permanent magnet synchronous ge nerator as the research object.The dynamic characteristics of the rotor,the electromagnetic design and optimization of the generator and the performance analysis and optimization based on the magnetic field analysis are studied respectively.Firstly,the structure and principle of the non contact electromagnetic loading system based on the electromagnetic torque of generator are introduced.Taking a high speed motor as an example,dynamic characteristic analysis models of the measured motor rotor and the test system rotor with the generator rotor are established and simulated by using ANSYS software.The critical speed and the vibration mode of the rotor are obtained based on the model.On this basis,the influence of the size of the generator rotor on the critical speed of the rotor system is further studied,and the limit condition of the rotor size is obtained under the condition of satisfying the critical speed safety margin.Secondly,the rotor of the generator is designed combining the limit condition of rotor dynamic characteristic with the limit condition of rotor mechanical strength and the main size formula in the electromagnetic design of the motor.The stator of the generator for loading are designed and optimized by using the magnetic circuit method and finite element method.Considering the two design requirements of high electromagnetic torque output and small rotor size,slot structure and slotless structure of the stator are designed and compared respectively.The stator with back around winding is also designed and compared with the traditional structure.The influence of inner and outer slot size on motor performance is analyzed by finite element method.Then,the subdomain method based on vector magnetic potenti al is used to solve unload,armature and load magnetic field of the loading generator,and the results are compared with the results of the finite element method.On the basis of the distribution of the magnetic field,the cogging torque and the electromagnetic torque are acquired,and the influence of the size parameters on the torque performance is analyzed.The energy method is used to calculate the armature inductance.The relationship between the electromagnetic torque and the load current of the generator and the method of improving the linearity of the electromagnetic torque and the load current are analyzed.Finally,the corresponding experimental verification is carried out for the permanent magnet synchronous loading generator.The loading test platform with the generator as the core is built.The unloading and loading experiment are carried out,and the relationship between the loading torque and the load current of the generator is measured to verify the loading validity.