High Efficient Digital Controlled Bridgeless Boost PFC without Direct Current Sensing

Modern power supplies require a power factor correction circuit (PFC) to comply with valid standards such as IEC 6100-3-2. Additionally, key points like the construction costs, construction size, electromagnetic compatibility (EMC) and the operating efficiency are always particular significance. Therefore, the highly efficient topology of a bridgeless boost PFC converter is applied here. In this case, an efficient control strategy is required. This paper presents the process of developing a low-loss digital control method without direct current sensing. Only voltage drops across the boost inductor and the output voltage are sampled. As a basis for the control circuit evaluation a state-space average (SSA) model of the power stage was created. Combined with that, the performance of the digital current controller could be analyzed and evaluated to establish the optimal setting. Finally, a holistic simulation constitutes the operation behavior of the control method in combination with the power stage.