Research On Control System For A Hybrid Excited Axial Field Flux-Switching Permanent Magnet Machine

Hybrid excited axial field flux-switching permanent magnet (HEAFFSPM) machine with both the permanent magnets and excitation windings in its stator is a novel hybrid excited synchronous machine (HESM). Due to the design concept of the flux-switching and hybrid excitation, the HEAFFSPM machine combines the advantages of the axial field flux-switching permanent magnet (AFFSPM) machine and HESM. Because of its hybrid excitation, the flux-focusing effect, shorter axial length, and double stator, the HEAFFSPM machine has many advantages including the simple structure, high power/torque density, larger flux-regulation capability, and easy to heat dissipation. So it is a good candidate for an electric traction system and other applications with a wide speed range drive. In this thesis, the key theoretical and technical issues on a 3-phase 12/10 poles HEAFFSPM machine drive system are systematically investigated by using the vector control (VC) and direct torque control (DTC) method, including the optimal efficiency strategy, cosφ=1, static and dynamic characteristics, and so on. This lays a theoretical and technical foundation for the applications of the HEAFFSPM machine in the electric drive system of the electric vehicles (EVs).The research achievements of this thesis are shown as follows:1. The research background, status and significance of the thesis are introduced and summarized. The topology and operating principle of the HEAFFSPM machine are analyzed in details. The simulation results of the electromagnetic characteristics including the back-EMF, flux-linkage, inductance and cogging torque are labored. The mathematical model of the HEAFFSPM machine in the abc, αβ and dq reference frame are obtained. Based on the MATLAB/Simulink platform, the simulation model of the HEAFFSPM machine is built and optimized.2. Based on the characteristics of the HEAFFSPM machine, the drive system for the HEAFFSPM machine is established. The operating performances of the HEAFFSPM machine are investigated by using the traditional control strategy in the VC method. Several control strategies including the cosφ= 1, minimum copper loss, flux-weakening control and fault-tolerant control for the HEAFFSPM machine are presented. The operating characteristics of the HEAFFSPM machine in the entire operating region are studied by the proposed control strategy, and compared with the results in the traditional control strategy. The results show that the proposed control strategies are validated and are also suitable for the HESM drive system.3. According to the VC method, an optimal efficiency strategy for the drive system of the HEAFFSPM machine is presented. Based on the MATLAB/Simulink and dSPACE, the operating performance of the HEAFFSPM machine is analyzed and researched by using the proposed control strategy. On this basis, the optimal efficiency strategy is optimized by adding the neural network control method. Finally, the performance of the HEAFFSPM machine drive system is improved and the proposed control strategy is validated.4. A sensorless DTC method for the drive system of the HEAFFSPM machine is proposed, and the relative theories are labored and deduced. A sliding model observer is designed for identifying the speed and rotor position of the HEAFFSPM machine. Based on the MATLAB/Simulink, the performance of the HEAFFSPM machine drive system is investigated by using the proposed control method. The sensorless DTC method is validated, and it lays a curtain foundation for the application of the DTC with sensorlees in HESM drive system.5. Based on the dSPACE1103, the experimental platform for the drive system of the HEAFFSPM machine is developed. Firstly, the hardware circuits of the HEAFFSPM machine drive system including the main drives, excitation drives etc. are designed. Secondly, the software programs are designed by using the MATLAB/Simulink and Real-Time Interface (RTI). Finally, according to the developed experimental platform, the operating performance of the HEAFFSPM machine in the whole operating region is investigated. The proposed control strategies are validated, and it lays a curtain theory and technology foundations for the further studies and industry application of the HEAFFSPM drive system.