Low-Complexity Model Predictive Control of AC/DC Converter With Constant Switching Frequency

Xingwu Yang,Yang Mi,Hao Li,Yani Wang,Yan Fang,Yang Fu

doi:10.1109/access.2020.3012163

Abstract

Conventional finite-control-set model predictive control (FCS-MPC) and low-complexity MPC (LC-MPC) may cause variable switching frequency and high sampling frequency. To address these concerns, a new LC-MPC scheme with a constant switching frequency has been proposed in this paper, the virtual voltage vector generated by two adjacent effective vectors applied to decrease the power control error. The scheme has been tested for power control of an AC/DC converter. Simulation and experimental results obtained have shown that the scheme generates smaller (near zero) power control error per switching period, and have a faster dynamic response and a constant switching frequency. These features have been attained without demanding for an excessively high sampling frequency. Finally, the comparison with the conventional methods is carried out in this paper, the advantages of the proposed method have been clearly illustrated.

Highlights

AC-DC converters have been extensively used in industrial applications such as motor drive, transmission system, uninterruptible power supply, distributed generator, micro grid,etc., [1]–[5]
EXPERIMENTAL RESULTS To verify the proposed low-complexity model predictive control (MPC) (LC-MPC) schemes, experimental tests have been performed with the schemes implemented with a floating-point, 150-MHz, TMS320F28335 digital signal processor (DSP)
This paper has proposed a new low-complexity MPC scheme for improving the performances of an AC/DC converter

Summary

INTRODUCTION

AC-DC converters have been extensively used in industrial applications such as motor drive, transmission system, uninterruptible power supply, distributed generator, micro grid,etc., [1]–[5]. One prediction is only required to find the optimal converter state represented by the so-called nearest voltage vector Such concept was expanded in [16] by using the negative conjugate complex power as the control variable. In [24], a new predictive-fixed current control was applied, which selected the optimal voltage vectors using a modulation scheme in the cost function minimization, and three voltage vectors were employed using a given switching pattern to work at a fixed switching frequency. B. TWO-VECTOR-TYPE LC-MPC the single-vector-type LC-MPC scheme described in the earlier section has greatly reduced computational burden, its steady-state tracking has not been impressive, since it uses only one non-zero or zero vector per sampling period. Two three-vector type LC-MPC methods are proposed on the basis of applying zero vector to modulation process to achieve an error-free power and constant switching frequency control. If b < 0.5a, which in Fig. 4, which corresponds to the smaller shaped triangle, the optimal vector should be the zero vector

PROPOSED THREE-VECTOR-TYPE LC-MPC

EXPERIMENTAL RESULTS

CONCLUSION