Abstract 

A Study on Modulated Carrier Control Method For Power Factor Correction Boost Converter As demand of electrical devices steeply increases, harmonic pollution on the power grid has attracted concern. This circumstance leads standards such as IEC61000-3-2 and 80-Plus regulating harmonic currents or PF (Power Factor) to have been more stringent. Thus, a PFC (Power Factor Correction) circuit able to improve power quality while reducing current harmonics has been indispensible at the electrical devices. For the reason, the PFC has been constantly researched so that various topologies and control types have been proposed and realized as silicon. So far, many of proposed PFC converters have each optimal operation mode offering good PFC performance such as CCM (Continuous Conduction Mode), DCM (Discontinuous Conduction Mode) or BCM (Boundary Conduction Mode). The same is true of Conventional Mcc (Modulated Carrier Control) PFC converters. The conventional MCC PFC method does not require sensing the line input voltage and offers very fast dynamic current control by directly comparing an inductor current. These are advantages of the conventional ones. However, these conventional MCC converters enter into DCM by load reduction, the line input current is distorted and harmonic current is increased. In this dissertation, a research on new MCC method is revealed from a study and analysis on the conventional MCC PFC converter. Two types of MCC method are proposed to overcome the problem of the conventional MCC aforementioned. The proposed MCC methods newly employ a circuit to detect DCM region and generate DCM compensation signal in common. Using the compensation, the MCC methods can control the line input current as a desirable sinusoidal waveform, which results in better PFC performance regardless of a line input voltage range or load variation unlike the conventional MCC method. With all them, the proposed method can maintain the advantages of the conventional MCC method and even it can be easily implemented with analog or digital circuits. This dissertation describes the proposed MCC methods and the operating principle. In addition, to verify the proposed methods, they are implemented in 400 W PFC boost converter.