Research On Adaptive Fuzzy-PID Control Of Flux-Switching Permanent Magnet Motors

As an alternative to other types of brushless machines, flux-switching permanent magnet (FSPM) machines have shown a number of potential benefits, including attractive torque output capability, high torque density, favorable thermal dissipation condition due to both magnets and armature coils locating in stator, as well as simple and robust rotor without PMs or coils, and have a bright future in the fields of electric vehicles drives applications.However, in order to overcome the nonlinearily electromagnetic performance of FSPM machines, such as magnetic saturation, coupled parameters and/or radial/axial flux leakage effects, the optimal design of machines itself, the lower total harmonics distortion (THD) of pulse width modulation method, and the advanced nonlinear control statergies are necessary.The focus of this thesis mainly on the research on the adaptive fuzzy control stratergies for speed regulator of the FSPM machine adjustable-speed drives (ASD), where the FSPM machine and inverter is regarded as a combined control plant. The inverter is voltage-fed and the modulation type is specifically space-vector pulse width modulation (SVPWM). Two different types of adaptive fuzzy control schemes, namely, adaptive fuzzy PID (AF-PED) and improved direct adaptive fuzzy (IDAF), as well as a robust digital torque observer are propsed and implemented. Aiming at the nonlinearity of primary parameters of the FSPM machine, the parameter sensitivity and the capability of disturbance rejection of the mentioned methodologies above are evaluated in Simulink platform and experiments, respectively. The main research contents of this thesis are summaried as below:(1) The contents and significances of this thesis are briefly introduced. Then, the operation priciple, structure character and mathematic model of FSPM machines are presented. Moreover, the modulation principle of SVPWM algorithms is analysed and the programming implementation is optimized.(2) The design methodology of current vector control adopoting sampled-data systems theory is analysed in detail, in which the deficiency of traditionally classical control theory directly using continuous time domain design is verified. Thus, a practical method based on successive loop closure of sampled-data systems is proposed for PM synchronous machines drive systems. In addition, based on Matlab Toolbox, a system identification method is adopted for experimental testing, laying a foundation for the rest analysis and measurements.(3) The basic theory of adaptive fuzzy PID is introduced, and then an AF-PID applied to the speed regulator of a FSPM machine ASD is analysed, designed and verified by simulations. The simulation results verify that the proposed algorithm has a lower parameter sensitivity and a stronger disturbance rejection capability.(4) Due to the poor parameter sensitivity of a traditional DTC open-loop flux observer, according to the digital control theory, a closed-loop digital flux observer based on the combined model of both voltage and current, and a current observer are analysed, designed, and verified by simulations. Further, the closed-loop digital flux observer can be treated not only as a general DTC torque flux observer, but also for the future research on deadbeat direct torque control (DBDTFC) of FSPM machines. At the same time, it provides an appropriate separation solution for DBDTFC experiments, i.e., the observers’parameters can be tuned in a CVC-ASD system in order to achieve satisfied dynamic performance. Afterwards, the dead-beat torque controller can be tuned with the fine tuned observers in a DBDTFC-ASD system.(5) The principles of direct adaptive fuzzy control (DAF) are described. According to the deficiency of digital DAF algorithms for FSPM machine drive systems, an improved direct adaptive fuzzy (IDAF) algorithm is proposed and studied with corresponding simulations. The simulation results show that the proposed algorithm has better command tracking and disturbance rejection abilities.(6) The hardware design for FSPM machine ASD system is completed, and wherein the schematic of analog signal processing circuits are simulatated to verify the accuracy of the design by using the step-by-step method of engineerings, in which the impact factors on the performance of actual control systems in simulation sessions are pointed out. Moreover, the necessary hardware configuration is analysed in detail, including voltage and current regulation circuits, position signal processing circuits, over-current and over-temperature protection circuits, power electronics circuits and drive circuits, etc.(7) The software design for the FSPM machine ASD system is completed. The digital controller used is TMS320F28335. Since the ADC module always generates sampling noise, the corresponding IIR digital filter is analysed and designed according to the characteristics of the FSPM machine ASD system. Following the 2015 version Motor WareTM Coding Standard, the IIR. digital filter algorithms and an AF-PID algorithm are implemented in CCS 6.1. The data structure of the algorithm and programming implementation process are showed. On the basis of 2013 version ControlSuiteTM open-source template, the software is rewritten and improved. The whole software and hardware of the FSPM machine ASD system are finally debugged.(8) A FSPM machine ASD system test platform is built, and the performance of the drive system is measured by experiments. According to the test methods and algorithms from simulations, a series of experiments verification and analysis of the results are conducted.