MPCC를 이용한 토템폴 브릿지리스 부스트 PFC 컨버터의 인터리빙 기법

Abstract

With the development of the electrical industry, AC-DC power converters are being used in various fields, and power factor correction is especially important in high-power applications. Accordingly, boost Power Factor Correction (PFC) converters are widely used, but conventional boost PFC converters using diode bridges have the problem of significant conduction losses. To solve this problem, various bridgeless PFC converters have been proposed, however the early versions had poor Electromagnetic Interference (EMI) characteristics due to Common Mode (CM) noise, and with continued development, totem-pole bridgeless PFC converters have recently attracted attention. In addition, for unity power factor correction in boost PFC converters, average current mode control and interleaving methods are commonly used. However, these methods have drawbacks such as slow dynamic response, complex implementation, and vulnerability to input voltage distortion. Consequently, Model Predictive Control (MPC) technique has gained recognition. In this paper, a variable sampling time interleaving method based on Finite Control Set Model Predictive Control (FCS-MPC) is proposed to enhance the current shaping capability, power conversion efficiency, power density, and current ripple reduction in totem-pole bridgeless boost PFC converters. The proposed method is based on FCS-MPC and has the advantage of being able to include nonlinear constraints among MPC. However, the ON/OFF switching of the switches is determined through model-based cost function comparisons, resulting in a variable switching frequency without the need for a separate modulator. Therefore, it is difficult to apply the conventional interleaving method using the phase shift of the existing Pulse Width Modulation (PWM) carrier wave. Accordingly, in order to reduce current ripple, a method was proposed to generate independent switching states for the two phases by varying the sampling time of the Model Predictive Current Control (MPCC) for single-phase current control. The proposed method was verified through real experiments on a 3.3kW totem-pole bridgeless boost PFC converter prototype.