Triple Loop Modulation (TLM) for High Reliability and Efficiency in a Power Factor Correction (PFC) System

The proposed triple loop modulation (TLM) can ensure reliability of the power factor correction (PFC) system due to the improvement of transient response. In conventional design, low bandwidth of less than 20 Hz that rejects ac source of 60/120 Hz coupling deteriorates system reliability in case of output load variation. Contrarily, the proposed TLM can automatically adjust bandwidth to rapidly increase or decrease inductor current to shorten transient response time. Besides, in the steady state, system stability can be guaranteed by low-frequency compensation pole without being affected by the TLM. The test circuit fabricated in a VIS 500 V UHV laterally diffused metal-oxide-semiconductor transistor process demonstrates that the highly integrated PFC controller with the proposed TLM has high power factor of 99%, high efficiency of 95%, and high power driving capability of about 90 W. The improvement in transient response is twofold faster than in conventional PFC design with output load variation from 90 to 20 W and vice versa.