Model prediction torque control method based on duty ratio

Abstract

The invention discloses a model prediction torque control method based on duty ratio. The method comprises the following steps: adding six virtual vectors on the basis of six basic effective vectors of the existing motor, and establishing a rotary coordinate system directed by a stator flux at the same time; dividing into four sectors according to the torque and flux increase-decrease demands, reducing the number of the candidate vectors and reducing the computing time if each sector in each control period comprises three candidate vectors; for three candidate voltage vectors, respectively computing the torque duty ratio with torque error as zero and the flux duty ratio with flux error as zero, at the end of this control period, of three candidate vectors according to the torque error andthe flux error, and providing a new optimal evaluation method according to the torque duty ratio and the flux duty ratio, wherein the optimal evaluation method does not need the evaluation function inthe tradition method, and the weight coefficient problem is eliminated; and the duty ratio algorithm is added to inhibit the torque pulse caused by the traditional single vector effect control at thesame time; the torque and the flux are simultaneously controlled when the weight factor problem is eliminated, and the torque and the flux have better control effect.

Description

technical field [0001] The invention relates to a predictive torque control method. In particular, it relates to a model predictive torque control method based on duty cycle. Background technique [0002] In industrial applications, permanent magnet synchronous motor (PMSM) control systems are widely used mainly due to their high precision, high efficiency, and excellent control performance. In the actual permanent magnet synchronous motor control system, fast dynamic response is the key factor to determine the performance of the whole system. Therefore, in order to improve the dynamic performance of the control system, model predictive torque control (MPTC) has been obtained due to its excellent dynamic response ability. Wide range of applications. In the traditional two-level inverter, six effective vectors and one zero vector can be generated, the motor state of the next cycle can be predicted through the motor model, and the optimal vector can be selected through the e...

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Problems solved by technology

[0003] In traditional model predictive torque control, in order to achieve simultaneous control of torque and flux linkage, the evaluation function usually includes torque error and flux error, but since torque and stator flux have different dimensions, in order to balance torque And the performance of flux linkage, the weight coefficient in the evaluation function is particularly important, but due to the lack of theoretical design process, adjusting the weight factor is a difficult task

In addition to the optimization task of weight factors, the model predictive torque control method also faces other challenges, such as high torque ripple and high computational burden

In the traditional method, the number of effective voltage vectors is too small, if one cycle acts on the entire effective vector, it will inevitably lead to excessive torque ripple

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