Direct torque control method suitable for multi-motor system

Abstract

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.

Description

technical field [0001] The invention belongs to the field of power converter control of driving motors, and in particular relates to a method for improving the performance of a multi-motor speed regulation system using direct torque control. Background technique [0002] In high-precision and high-speed transmission systems such as papermaking, textiles, printing and dyeing, and steel rolling, multi-motor synchronous control has always been the core issue. Multi-motor synchronization includes that each motor has the same speed; the speed of multiple motors maintains a fixed ratio, such as synchronous rolling mills, paper machines, textile dyeing and finishing machinery, etc.; the rotation angle or displacement of the output shafts of multiple motors is kept constant as required Differences, such as precision CNC machining equipment, filament winding and weaving equipment, robot control, etc. The purpose of synchronous control is to make the tracking error and synchronizatio...

AI Technical Summary

Problems solved by technology

Direct torque control adopts the control structure of hysteresis comparator and switch table, which has the advantages of simple structure, no dependence on motor parameters and no need for rotation coordinate transformation, but it has the problem of large torque fluctuations

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