Design and Controller Optimization of Switched Reluctance and Flux Switching PM Machines.

SIKDER, CHANDAN. Design and Controller Optimization of Switched Reluctance and Flux Switching PM Machines (Under the direction of Dr. Iqbal Husain). This dissertation presents the design, modeling, control and implementation of two different radial flux electric machine topologies that use the same type of rotor with several specific objectives and requirements. Flux Switching PM (FSPM) machine is one of those machines which can be seen as an improved or modified version of the other which is the Switched Reluctance Machine (SRM) with better performance and higher power density. A novel control technique for SRM is developed to maximize efficiency for a wide speed range. A geometry based analytical model was used to establish the concept and develop the control algorithm. Based on the simulation results, a correlation have been found between Switched Reluctance Generator (SRG) system efficiency and DC-link current ripple. A novel control algorithm has been developed that dynamically varies the commutation angles for the machine operation based on the required and commanded DC-link current along with continuously monitoring the ripple in DC-link current. The algorithm is implemented and successfully tested on a 1kW SRM drive. This control concept can generally be applied to any SRM for all speed ranges. FSPM machine is one of the newer topologies that emerged as a potential alternative candidate to the existing popular topologies due to its ability to combine most of the features and advantages of SRM and conventional PM machines into one structure. This dissertation presents a methodology for designing low torque ripple FSPM by addressing the issue of cogging torque by rotor pole shaping. A generalized design rule on rotor pole shaping has been developed using permeance based model for cogging torque minimization. The proposed pole shaping is shown to minimize the torque ripple to up to 97% with only 5.34% sacrifice on the average torque. The issue of noise, vibration and stator deformation are also addressed from a design perspective. An analytical model has been proposed and verified with FEA to account for the natural mode frequencies of the segmented stator of FSPM. Based on the analytical model of natural mode frequencies, another design rule has been proposed to improve the noise and vibration characteristics of the machine. The proposed design modification reduces noise by 7-8 dB at all the operating speeds, whereas the stator deformation is within acceptable limits as found from structural FEA. An accurate machine model incorporating saturation and mutual coupling has been developed using FEA based dand q-axes flux linkage characteristics. The performance of the motor drive has been verified before fabrication using a coupled simulation of the FEA machine model and a dynamic simulation model of the controller and drive. An experimental prototype of the designed 0.5kW, 12/10 FSPM machine was constructed with non-rare earth PM applying the design rules for reduction of cogging torque and acoustic noise. Based on the developed machine model and coupled simulation, stator field oriented vector controller has been implemented in the experimental setup. No-load back EMF, steady state torque and phase current waveforms have been collected from the experimental setup to evaluate and verify the motor drive system performance at different operating speeds and for up to 200% rated load. All the tests show excellent correlation to the FEA analysis and cosimulation results. In addition, a steady state heat run test was also performed to examine the temperature rise in different parts of the machine according to the losses. © Copyright 2016 Chandan Sikder All Rights Reserved Design and Controller Optimization of Switched Reluctance and Flux Switching PM Machines