Adaptive Selective Harmonic Elimination Model Predictive Control for Three-Level T-Type Inverter

Jianfeng Hong,Renxian Cao

doi:10.1109/access.2020.3020216

Abstract

In this work, an adaptive selective harmonic elimination model predictive control (ASHEMPC) method for a 3L-T type inverter is proposed. This algorithm is based on model predictive control (MPC), introduces adaptive selective harmonic elimination (ASHE) algorithm, and performs digital delay compensation through two-step prediction. Compared with the harmonic suppression strategies based on PI or PR controller, ASHE-MPC significantly improves the current loop bandwidth, speeds up the dynamic response, and greatly increases the harmonic order that can be eliminated. Compared with the harmonic suppression strategies based on the deadbeat model predictive control (DB-MPC), ASHE-MPC can eliminate low-order harmonics caused by multiple factors (including dead-time and grid background harmonics), and can easily eliminate multiple harmonics (5 th -31 th in this paper). The proposed ASHE-MPC method for the first time achieves adaptive selective harmonic elimination in model predictive control. The ASHE-MPC method is novel, simple and efficient. A three-level T-type grid-connected inverter for dead-time compensation is used as an example to verify the feasibility of this method.

Highlights

In recent years, distributed grid-connected power generation based on renewable energy sources such as wind energy and solar power has received increasing attention and has become a research focus
In order to verify the effectiveness of the proposed AHSE-model predictive control (MPC) method, the simulations were performed with uncompensated dead time without and with adaptive selective harmonic elimination (ASHE) algorithms
In order to highlight the superiority of the AHSE-MPC method over the ASHE-PI method, simulations are performed on the ASHE-PI method

Summary

INTRODUCTION

In recent years, distributed grid-connected power generation based on renewable energy sources such as wind energy and solar power has received increasing attention and has become a research focus. The disadvantages of PI-IMP are as follows: Multiple coordinate transformations bring a large computational burden to the processor, and the use of a low-pass filter will introduce a phase delay; with the increase of the harmonic order to be suppressed, the PI controller-based current loop cannot provide a sufficiently high bandwidth, which results in a very low harmonic order that can be suppressed; at the same time, a small current loop bandwidth results in a slow dynamic response. The above three IMP-based harmonic suppression strategies have the following disadvantages: current loop bandwidth is small, dynamic response is slow, the number of harmonics that can be suppressed is small, digital implementation of the controller is difficult, and control strategies are very sensitive to grid frequency fluctuations. This paper proposes an adaptive selective harmonic elimination model predictive control (ASHE-MPC) method.

SYSTEM MODEL DESCRIPTION

THE PRICIPLE AND IMPLEMENTATION OF AHSE ALGORITHM BASED ON PI CONTROLLER

THE SIMULATION RESULTS

VIII. CONCLUSION