Fault-tolerant direct torque control method for six-phase permanent magnet synchronous motor lacking any two phases of windings

Abstract

The invention relates to a fault-tolerant direct torque control method for a six-phase permanent magnet synchronous motor lacking any two phases of windings. The method includes the steps that remaining healthy phase currents from ic to if and a rotor position angle are collected; the remaining healthy four phases of currents from ic to if are converted into isalphaisbeta and iszlisz2; virtual stator currents ixsalphaixsbeta are calculated; a virtual stator flux linkage psixsalphapsixsbeta is calculated; the number thetaxsi of an alphabeta plane sector where a vector of the virtual stator flux linkage psixsalphapsixsbeta is located is judged; a variable phi for controlling the amplitude of the virtual stator flux linkage is output; an electromagnetic torque Te is calculated; a variable tau for controlling the electromagnetic torque is output; a zero-sequence current error delta isz is output; delta isz, tau, phi and thetaxsi are sent to an optimal switch vector table so that an optimal switch combination can be obtained, and the optimal switch combination acts on remaining four healthy phases of windings so that the control target that the error of zero-sequence currents, the amplitude of the virtual stator flux linkage and the electromagnetic torque is zero can be achieved. The control method solves the problem of how to make a 60-degree-bias six-phase permanent magnet synchronous motor direct torque control drive system continue to operate when two phases of the windings of the motor are disconnected or two phases of windings of an inverter bridge break down.

Description

technical field [0001] The invention relates to a fault-tolerant direct torque control method for a six-phase permanent magnet synchronous motor lacking any two phases. Background technique [0002] Since multi-phase motors have more control degrees of freedom, when windings or power electronic converters fail, they can flexibly achieve fault-tolerant operation, so they are increasingly used in key fields such as military equipment propulsion systems, aerospace propulsion systems, and rail transit traction systems. Get favor and use. Moreover, these occasions also require a strong torque control capability. At present, the direct torque control (DTC) strategy has been studied in detail when the windings of multi-phase motors are fault-free. Even so, there are few researches on direct torque control fault-tolerant strategies when the winding or inverter fails, especially in the multi-phase permanent magnet synchronous motor. [0003] For multi-phase motor DTC drive systems...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a six-phase permanent magnet synchronous motor lacking any two-phase fault-tolerant direct torque control method. Difficulties in continuing operation after phase break or inverter bridge two-phase failure

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