A modified predictive control strategy of three-phase grid-connected converters with optimized action time sequence

To improve the performance of three-phase voltage source pulse-width modulated (PWM) rectifiers (VSR) under unbalanced grid voltage conditions, a fixed-frequency current predictive control (CPC) strategy is presented. Instantaneous power of the three-phase VSR is analysed in a two-phase stationary frame. The calculation method for the reference current is improved to achieve the power stability at the AC side of the rectifier. Based on the current predictive model, the optimal duration of the voltage vectors is computed under the restricted condition of minimizing current error at α- and β-axes in fixed intervals. The control system is free of synchronous rotation coordinate transformation, and avoids positive and negative sequence decomposition, which simplifies the calculation. The simulation and experimental results show that the proposed control strategy is able to eliminate the AC current distortion effectively and depress DC link voltage fluctuation under unbalanced grid voltage. Furthermore, the control strategy has faster dynamic response ability, enhancing the control performance of the three-phase VSR system.

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Carrier-Based Modulated Model Predictive Control Strategy for Three-Phase Two-level VSIs

IEEE Transactions on Energy Conversion ◽

10.1109/tec.2021.3073110 ◽

2021 ◽

pp. 1-1

Author(s):

Junzhong Xu ◽

Thiago Batista Soeiro ◽

Fei Gao ◽

Linglin Chen ◽

Hou-Jun Tang ◽

...

Keyword(s):

Model Predictive Control ◽

Predictive Control ◽

Control Strategy ◽

Three Phase

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Sequential Model Predictive Control of Three-Phase Direct Matrix Converter

Energies ◽

10.3390/en12020214 ◽

2019 ◽

Vol 12 (2) ◽

pp. 214 ◽

Cited By ~ 5

Author(s):

Jianwei Zhang ◽

Margarita Norambuena ◽

Li Li ◽

David Dorrell ◽

Jose Rodriguez

Keyword(s):

Model Predictive Control ◽

Predictive Control ◽

Control Strategy ◽

Weighting Factor ◽

Matrix Converter ◽

Cost Functions ◽

Computational Burden ◽

Three Phase ◽

The Matrix ◽

Factor Design

The matrix converter (MC) is a promising converter that performs the direct AC-to-AC conversion. Model predictive control (MPC) is a simple and powerful tool for power electronic converters, including the MC. However, weighting factor design and heavy computational burden impose significant challenges for this control strategy. This paper investigates the generalized sequential MPC (SMPC) for a three-phase direct MC. In this control strategy, each control objective has an individual cost function and these cost functions are evaluated sequentially based on priority. The complex weighting factor design process is not required. Compared with the standard MPC, the computation burden is reduced because only the pre-selected switch states are evaluated in the second and subsequent sequential cost functions. In addition, the prediction model computation for the following cost functions is also reduced. Specifying the priority for control objectives can be achieved. A comparative study with traditional MPC is carried out both in simulation and an experiment. Comparable control performance to the traditional MPC is achieved. This controller is suitable for the MC because of the reduced computational burden. Simulation and experimental results verify the effectiveness of the proposed strategy.

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