Research Of Topology And Control Algorithmof Flux-switching Machines With Non-overlapping Concentrated Windings

FSPM machine with non-overlapping concentrated windings combines the robust rotor structure of SRM and high power density of PMSM with the reliability of non-overlapping winding machines. The machine meets the requirements of both electric actuator of electric/more electric aircrafts and electric motors used in electric vehicles. So the system of FSPM machine with non-overlapping concentrated windings is studied and the control algorithm is researched systematically.In order to reduce the torque ripple and harmonic content in the back-EMF waveform of FSPM machine with non-overlapping concentrated windings, this paper proposes a kind of twist-rotor structure and the method to choose the best twist angle. The method takes account of both flux-linkage and cogging torque. The simulation and experimental results show that the method can reduce the torque ripple effectively without torque reduction. The method is generalized to various structures of FSPM machines.Since the harmonic of back-EMF and resistance of winding are ignored in present fault-tolerant control strategies, control strategy considering second harmonic back-EMF is studied. When the open-circuit fault occurs, amplitudes and phases of healthy phases are adjusted to maintain the average output torque and reduce the torque ripple. In condition to short-circuit fault, according to the measurement result of short-circuit current, the back-EMF of the fault phase can be obtained considering both the inductance and resistance, then the currents can be obtained based on fault decomposition. Experiments are taken to verify the fault-tolerant control strategy. And comparion has been made with other two present control strategies.Lastly, aimed to applications requiring good dynamic performace, direct torque control of multi-phase system is studied. A selection method combining short with long vectors is studied to reduce torque ripple and make full use of voltage vectors. Based on theoretical analysis of the effect of voltage vector with different amplitudes or phases on dynamic response and torque ripple, the vector which changes torque fastest is chosen when the load torque or given speed changes and the vector which changes torque most slowly is chosen when the system is in stable. Experiments are taken on the prototype machine to verify the fault-tolerant control strategy.