Control of multiple single-phase PFC modules with a single low-cost DSP

In this paper, a new control scheme is proposed for controlling multiple single-phase power-factor-correction (PFC) modules with a single low-cost digital signal processor (DSP). The proposed scheme allows for multiple PFC modules of different current ratings to be operated in parallel and controlled via a single DSP. DSP-based control handles simple current sharing and provides size reduction. The paper describes a current sense technique for each PFC module and a closed-loop control algorithm for output voltage and input current control for operating multiple modules. In the example design, switching frequency is set at 120 kHz and two continuous conduction mode PFC stages are operated in parallel and controlled via a single TMS320LF2407 DSP. Experimental results show that the proposed scheme is capable to be used for modern switching power supplies.