Performance Evaluation of a Digitally Controlled Boost Converter PFC Operating in Critically Continuous Conduction Mode

摘要

The research aims to implement a boost power factor corrector (PFC) operating in critically continuous conduction mode controlled by digital signal processor (DSP). A unit was built and tested which has DSP for converter control and system supervisory. For the converter control, the use of the Constant On-time control is used to drive the Power MOSFETs of the converter and Proportional-Integral control for the system stability and bulk voltage regulation. For the system supervisory, it involves the fault protection of the unit such as Over-voltage Protection (OVP), Over-power Protection (OPP), In-rush Current Limiting, Over-temperature Protection (OTP) and State Machine. Results showed that prototype has an output voltage of 390 ± 4%V and has a worst line regulation of 1.3%. For the efficiency, it acquired a 94. 74% for 115Vrms input and 96.26% for 230Vrms input both at full-load conditions. For the power factor (PF), the unit passed the 80 Plus Gold Power Factor Standard to have a PF of greater than 0.9 at load greater than 75W. It also passed the stability requirement of at least -6dB gain margin and 45° phase margin and passed the EN55032 Conducted EMI Emission Class A Standard and EN61000-3-2 for Harmonic Currents Emission.