Study of Constant DC-Voltage Control for VIENNA Rectifier Under No-Load Condition

VIENNA rectifier has emerged as a promising topology for ac–dc power converter, but it has the problem of dc-link output voltage surge under no-load condition. In this article, a high-reliability hardware auxiliary circuit and an easy-implement software regulation algorithm are proposed to achieve voltage stability. First, voltage-oriented current cross-decoupling control strategy is introduced and the reason of the voltage surge has been analyzed using equivalent circuit model. Second, the equivalent circuit model of different working state for auxiliary circuit in association with VIENNA rectifier are described, along with introducing the selection of device parameters in the auxiliary circuit. Meanwhile, the mechanism of two working modes in the software regulation algorithm is analyzed to make the VIENNA work in boost and buck mode to achieve dc-voltage stability. Finally, the feasibility and effectiveness of the proposed methods have been verified using experimental results. The proposed methods not only suppress the dc-voltage surge but also exhibit a good performance in terms of supply-side power factor (PF) and dc voltage in a VIENNA rectifier, meanwhile maintaining the system adaptability under circumstance of the load step.

I. Introduction

With the development of power electronics, higher requirements are put forward for the rectifiers. Pulsewidth-modulated (PWM) rectifiers including two- and three-level unidirectional PWM rectifiers have advantages over diode bridge rectifiers because of low input current total harmonic distortion (THD) and controllable power factor (PF) [1], [2], [3]. Comparing with conventional unidirectional PWM rectifiers, the three-phase VIENNA rectifier has many advantages of lower cost, lower current THD, no dead zone for switching signal lower [4], [5], [6], lower semiconductor device voltage stress, higher power density, and higher efficiency [7], [8], [9]. Due to these characteristics, VIENNA rectifier is widely used in telecommunication power systems, electric vehicle (EV) charging pile and wind turbine systems, and PF correction systems, where high-power density and low device voltage stresses are required [8], [10], [11].