A Predictive Direct Torque Control Method for Two Motors in Series

Abstract

The invention relates to a double-motor series prediction type direct torque control method. Electromagnetic torque pulsation of two motors is reduced and the operation stability of a drive system is further improved. A zero sequence current is actively controlled, the distortion of a winding current is reduced, and the stable operation performance of the two motors is improved. In order to reduce system control operation time and improve the digital control rapidity, a prediction type electromagnetic torque and stator flux linkage control method of a partial voltage vector of which zero sequence plane voltage is 0 is employed. Through real-time adjustment of the action time of 0 and 21 or 0 and 42 voltage vectors, the control that the zero sequence current is 0 is realized.

Description

technical field [0001] The invention relates to a double-motor serial predictive direct torque control method. Background technique [0002] The power supply mode of a single motor using a single inverter is a traditional motor drive mode. This structure is simple to control, but due to the large number of inverters used, the cost of the entire drive system is high and the system reliability is low. In many occasions, there are multiple motors running. In order to reduce the driving cost and improve the reliability of the system, multiple motors can be connected in series and a single inverter can be used for power supply. [0003] Single six-phase inverter powered six-phase series three-phase double permanent magnet synchronous motor drive system is a commonly used drive structure. One-phase windings are connected in series, so that the current of the three-phase windings is equally divided into the two-phase windings of the parallel-connected six-phase motor. The current...

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Problems solved by technology

[0004] The six-phase inverter can output 64 kinds of voltage vectors. The storage space of the switch vector table in the traditional multi-phase motor drive direct torque control strategy based on the optimal switch vector table is very large, and the hysteresis comparator control method brings relatively large Large electromagnetic torque ripple and current ripple, deteriorating the decoupling and stable operation characteristics between the two motors

If this degree of freedom cannot be well controlled, it will directly deteriorate the steady-state operating performance of the actual drive system, such as serious distortion of winding current, increased copper and iron loss of the two motors, etc.

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