Research On Flux-weakening Control Of Hybridly Excited Asymmetric Stator Pole Doubly Salient Machine

Hybridly Excited Asymmetric Stator Pole Doubly Salient Machine(HEASPDSM)is a new type of Hybrid Excitation Synhronous Machine.Its permanent magnets and DC excitation winding are located on the stator,and there is no permanent magnets and windings on the rotors.The simple structure makes this motor suitable for high-speed operation,so that it has broad application prospects in electric drive systems such as electric vehicles and ship electric propulsion.In this thesis,a 12/7 HEASPDSM prototype is studied.Based on the analysis of its operation principle and electromagnetic characteristics,a vector control system is established and two flux-weakening control schemes of HEASPDSM are studied to enhance the flux at low speed and weaken the flux at high speed range,which provides a reference for the application of HEASPDSM.Main contents of this thesis are as follows:1.The flux adjustment principal of HEASPDSM is analyzed,and the electromagnetic characteristics are introduced with the finite element simulation results.Then the mathematical model in the three-phase stationary and two-phase rotating coordinate system is established,and the flux adjustment capability of the excitation winding is analyzed.The above analysis and conclusions provided a theoretical basis for the study of the flux-weakening control scheme.2.According to the mathematical model in dq coordinate system and the characteristics of HASPDSM,the vector control system of HEASPDSM is established,and the simulation model based on MATLAB/Simulink is built.In order to enhance the output torque at low speed and increase the speed range,the speed-torque characteristic curve of HEASPDSM and the constraints of flux weakening are analyzed,and an improved speed-range driving control scheme based on mathematical model is proposed.It can effectively increase the speed range.3.Because of the high tolerance to motor parameters for speed-range driving control,a voltage-regulation flux weakening control strategy combined with MTPA is proposed,which is simple and practical.The excitation current is controlled according to the speed-range division by this control scheme.It can improve the output torque in the full speed range and enhance the dynamic response performance in the high-speed flux-weakening region.4.A drive system of HEASPDSM is designed and a test platform is built.Then the magnetic-regulation performance experiment is completed on the platform,and the results are consistent with the finite element simulation results.Finally,the low-speed steady-state experiment and high-speed flux-weakening experiment are completed,which verified the effectiveness and feasibility of the aforementioned control strategy.