Dual three-level inverter model prediction fault-tolerant control strategy

Abstract

The invention provides a dual three-level inverter model prediction fault-tolerant control strategy. In a value function, by using the stator current as a tracking target, the constraint of mid-pointpotential balance is introduced to adjust the DC bus voltage, and the constraint term of the switching frequency is added. Then, a zero-sequence loop is limited based on the degree of freedom of the zero-sequence voltage, and during a single-arm fault, an available zero common-mode vector is selected as an optimized target vector so as to eliminate the zero-sequence current and greatly reduce thecalculation delay. In the case of a single-transistor fault, the available zero common-mode vector cannot satisfy the control needs, and the subset of the optimized switch vector is selected discretely. Finally, the proposed scheme is verified by simulation and compared with a traditional scheme, and a result verifies the effectiveness and feasibility of the proposed method.

Description

technical field [0001] The invention belongs to the technical field of double three-level inverters, and in particular relates to a model predictive fault-tolerant control strategy for double three-level inverters. Background technique [0002] Asynchronous motors are widely used in 70% of the occasions because of their ruggedness, simple structure, easy maintenance, high operating efficiency, and simple manufacturing process. However, due to the needs of high voltage, high power, and good output waveforms, traditional topologies The withstand voltage and common mode voltage problems of switching devices restrict the development of asynchronous motors. In 2000, scholars E.G.Shivakumar and K.Gopakumar proposed the topology of an open-winding motor fed by dual inverters. The open-winding topology is to open the star-shaped neutral point of the stator winding and the two ends are separated by two inverters The unique structure of the feed. The topology of the dual inverter ha...

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Problems solved by technology

Some characterize a method that divides the switching vectors into 6 sectors while taking advantage of the positive and negative relationship between the torque error and zero, reducing the switching vectors from 19 to 6, however, rolling optimization for model predictive torque control The quantity is the torque and flux linkage, which has a longer calculation delay than the single rolling optimization quantity of the model predictive current control. In addition, the model predictive torque control has larger current and torque ripples. For the dual three-level inverter For the fault-tolerant control of the inverter, it is obvious that the model predictive current control is a better choice

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