An optimization method for direct torque control of open-winding motor under variable bus voltage conditions

Abstract

The invention discloses a direct torque control optimization method under the condition of variable bus voltage of an open-winding motor, aiming at reducing the difference between the increase and decrease of the torque change within a unit control cycle, and optimizing the selection of the switch table control strategy In the space voltage vector, reduce the output torque ripple of the open-winding motor under the direct torque control based on the switch table, and take the ratio of the dual power bus voltage as the control variable, combined with the position of the stator flux linkage in the eighteen sectors The position and output signal of the hysteresis controller are used to select the switch table online to realize the optimal control of the open-winding permanent magnet motor under the condition of variable bus voltage. The control method can effectively improve the driving output performance of the open-winding motor under the condition of battery power supply.

Description

technical field [0001] The invention relates to a direct torque control optimization method suitable for an open-winding permanent magnet motor under variable bus voltage conditions, and belongs to the field of motor systems and controls. Background technique [0002] The open-winding motor is an AC motor in which the neutral point of the armature winding of the motor is opened without changing the magnetic circuit and structure of the traditional three-phase AC motor, and the two ends are respectively controlled by a three-phase converter. Compared with the traditional three-phase AC motor, not only the basic performance of the open-winding motor will not be affected, but also the windings of the open-winding motor are relatively independent, and the reliability of the motor body will be improved to a certain extent; In the converter control system, it can be equivalent to a three- or four-level system, and there is no midpoint voltage balance problem inherent in multi-leve...

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Problems solved by technology

[0007] 3) As the charging and discharging process continues to cycle, the performance degradation of the battery pack will also lead to a decrease in the voltage output capability

[0008] The distribution of the voltage space vector in the system is closely related to the voltage amplitude of the bus bars on both sides. In addition to the above-mentioned problem that the voltage of the power battery pack will change during the actual charging and discharging process, affected by the characteristics of the power supply, there are many problems in the open-winding motor drive system. The change of the bus voltage amplitude will lead to the change of the space voltage vector amplitude and the angle relationship between them. The voltage vector synthesized by the bus voltage will inevitably lead to the deterioration of control performance and may even lead to system instability. Therefore, it is necessary to make targeted improvements to the switch table under variable voltage conditions to improve the performance of the open-winding motor DTC system. performance

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