Improved two-vector direct power control algorithm-based three-phase pulse width modulation rectifier

Direct power control (DPC) has received a significant amount of research attention because of its benefits such as simplicity, robustness and excellent dynamic response. Conventional switching-table-based single-vector DPC (SV-DPC) presents irregular power ripples and variable switching frequency, due to the use of predefined switching table and hysteresis comparators. To solve these problems, two-vector DPC (TV-DPC) and three-vector DPC (THV-DPC) based three-phase pulse width modulation (PWM) rectifier are proposed. Although the performance of the THV-DPC is better than that of TV-DPC, its algorithm implementation is very complex and time consuming. In this paper, two-three combined vector DPC (TTCV-DPC) algorithm is presented which combines two and three voltage vectors by the help of the new switching table. The proposed algorithm has less complexity than the THV-DPC and better performance than the TV-DPC. Comprehensive simulations demonstrate the proposed method can get lower power ripple and lower grid-side current total harmonic distortion (THD) than that of TV-DPC.

I. Introduction

Recently, three-phase pulse width modulation (PWM) rectifier has been widely applied to the areas of ac adjustable speed drives, active power filter, distributed generation and voltage source converter transmission. Compared to passive diode rectifier, the PWM rectifier has the advantages of bidirectional power flow, sinusoidal line current, controllable power factor, and good dc-link voltage regulation ability with a small-size capacitor [1], [2]. Various methods have been proposed to achieve power control of PWM rectifiers and they can be classified into four groups [1]–[3]: voltage-oriented control (VOC), voltage-based direct power control (DPC), virtual-flux oriented control (VFOC), and virtual-flux-based DPC.