Control of a Single-Phase PFC Preregultaor using an 8-bit Microcontroller

Abstract

Presented in this paper is a hybrid power factor correction (PFC) preregulator controlled by a single microcontroller. By using the on-board peripherals of this microcontroller, no complex algorithm or external multiplier was required to perform the PFC function correctly, and thus a onechip solution has been achieved. The proposed hybrid PFC preregulator has been tested in the laboratory. The measured power factor was above 0.99, and the output voltage was precisely controlled. Experimental results also indicate that the hybrid PFC preregulator can operate satisfactorily over a range of input voltages and output loads. The results presented in this paper demonstrate that it is possible to implement a high performance PFC preregulator using a single microcontroller without more expensive DSPs or other complicated hardware. Because of the simplicity of the circuit, the proposed PFC preregulator has low cost and high reliability.

Single comparator based A/D converter for output voltage sensing in power factor correction rectifiers

“…However, around regulation (d comp = 0.5, V e = 0) the linearly approximated SCA/D given by (3) reports an error voltage of zero regardless of the power processing level of the PFC stage. Also, with V K chosen according to (4), it is apparent that the gain (slope) of the linearly approximated SCA/D matches the gain of the ideal SCA/D around regulation at rated power.…”

“…Many implementations of digital voltage loops for use in power factor correction (PFC) rectifiers have been proposed to either improve the dynamic response to line and load transients [1]- [3] or reduce the hardware complexity of a complete PFC controller [4], [5]. In all cases the scaled output voltage (H v V o ) or the scaled error voltage (H v V e ) of the PFC stage was sampled using a medium resolution (8-10 bit) analog to digital converter (A/D).…”