Single-switch power factor correction AC/DC converter with storage capacitor size reduction

In universal line applications with hold-up time requirement, the single-stage PFC AC/DC converters may not be more attractive than the conventional two-stages approach if the size and cost of the storage capacitor are too high. Furthermore, computer related applications, in which the holdup time is a very important requirement, will have to comply with Class D limits of the low frequency harmonic regulation IEC 61000-3-2. Therefore, for these applications, a not very distorted line current will be required. In this paper, a new single-stage AC/DC converter suitable for universal line applications is proposed. The main difference with other solutions is the low voltage swing on the storage capacitor while the line varies within its universal range. This feature allows reducing the size and cost of the storage capacitor. Additional advantages of the proposed converter are topology simplicity (single-switch converter) and IEC 61000-3-2 Class D compliance. The experimental results confirms the above mentioned advantages.