| It is difficult for conventional motors to simultaneously achieve high output torque in constant torque region, as well as wide speed operation in constant power region, as a result, the industrial application of which is inevitably limited. Memory machine (MM), which employs PM with intrinsically low coercivity and high remanence was extensively investigated recently. It can achieve efficient online flux-adjustment by applying a temporary remagnetizing or demagnetizing current pulse to vary the magnetization state of the PM, thereby exhibiting advantageous feasibility for wide speed range operations. This thesis focuses on the flux regulation and drive system of a newly emerged flux-switching memory machines (FSMMs).Firstly, the flux-memory characteristics of AlNiCo PM are introduced, and the recent development of MMs is reviewed including machine topologies and control schemes. Then the topology of FSMM to be controlled is briefly introduced and the mathematic model is derived. In order to get high output torque in constant torque region and wide speed range at the same time, a new control strategy which integrates conventional flux-weakening scheme with online magnetization control is proposed based on the detailed analysis of operation regions of the machine. The id=0 control scheme is implemented in constant torque region. A parameter-independent flux-weakening scheme is investigated and improved. To ensure accurate flux regulation, a sliding mode PM flux observer based on q-axis voltage equation is designed. The operating stability and parameter selection criterion of the observer are analyzed. The controller parameters of PI regulators for current loop, speed loop, and magnetizing windings are designed. A simulation model of the machine is built with the aid of MATLAB/Simulink to analyze the on-load flux-regulation ability in constant torque region as well as the effectiveness of the proposed PM flux observer and flux-weakening scheme.Finally, the control system for a FSMM prototype is constructed on the basis of DSP TMS320F28335. The machine controller is implemented in terms of hardware circuit and software program, and the experiments are carried out. Experimental results preliminarily verify the on-load and flux regulation ability of the machine. |
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