Direct torque control method suitable for multi-motor system

The invention discloses a direct torque control method suitable for a multi-motor system. Firstly, a torque and flux linkage evaluating function of the multi-motor system is established; a torque and flux linkage impact factor table is obtained through the discretization and equalization processing on the evaluating function; then, the torque reference value of a single motor is generated through a deviation coupling controller of the multi-motor system; lastly, a torque impact factor reference value p Tau* and a flux linkage impact factor reference value p Lambada* are calculated, an objective function is established, and an inverter voltage vector enabling the value of the objective function to be minimum is selected according to the torque and flux linkage impact factor table and is used for controlling the multi-motor system. According to the direct torque control method, fast torque responses of the multi-motor system can be achieved, and torque ripples in steady-state operation can be lowered; the impact degrees of different inverter voltage vectors on the electromagnetic torque and the motor stator flux linkage amplitude of the multi-motor system under the action of different duty ratios can be comprehensively, directly and finely reflected through the established torque and flux linkage impact factor table.