Direct Torque Control Of Fault Tolerant Permanent Magnet Motor

For Fault tolerant permanent magnet (FTPM) motor has the ability of fault toleration andisolation, thus it has broad application prospects in the more electric/all electric aircraft power actuator.In order to ensure the high reliability of the Fault Tolerant Permanent Magnet Motor Control System,the Direct Torque Control is applied to the Fault Tolerant Permanent Magnet Motor with six-phaseten pole structure.In this paper, the FTPM motor drive system is based on separate H-bridge rather than three phasefull-bridge, meanwhile the FTPM motor drive system has no neutral point, as a result the distributionof the total space voltage vector based on FTPM motor is quite different form that of three-phasefull-bridge drive motor, thus the distribution of the total space voltage vector is firstly to be discussed.Then follow the three-phase motor direct torque control of six sector and Circular flux trajectorymethod, the DTC on FTPM motor is proposed. A novol flux observer is bulid based on the magneticisolation of the motor. Some simulation, experimental verification and theoretical analysis are takenon Bang-Bang DTC. From these results, it can be deduced that the number of constraints of thesystem is less than that of variables. The variable strength of the constraints is not enough, whichdirectly lead to distort of the current.In order to overcome these shortcomings mentioned above, the SVM-DTC of FTPM motor isestablished, the stratagy create the total space voltage vector by directly using six single phasewinding phase space voltage vector, and the synthetical space voltage vector could achive flux andtorque control. For the stratagy directly use the single phase winding voltage vector to control thetorque and flux, the distortion of current could be avoid. Meanwhile, for the system have faulttolerance requirements, the fault-tolerant stratagy is given (including one-phase short-circuit andopen circuit). A series of of simulation and experimental studies on FTPM motor are taken, theseresults verified the feasibility, correctness, and fault tolerance abilty of the system.In this paper, control programs of DTC is written in assembly language, these experiments aretaken on a digital control system experimental platform based on TMS320LF2407to realise DTC onFault Tolerant Permanent Magnet Motor under normal and fault states.