The Research Application Of 4H-SiC SBD In The Power Factor Correction Circuit

Wide bandgap semiconductor material SiC, following Si and GaAs, is a new generation semiconductor material and it has excellent properties such as wide bandgap, high breakdown field, high thermal conductivity and good reverse recovery character. SiC Schottky diode can reduce the switching loss and help the implement of high switching frequency in high power CCM APFC.In this thesis, the characters of SiC SBD, the definition and the calculation of power factor and the switching loss of components in Boost APFC are analyzed in detail, and the topologies and the control methods of all kinds of PFC, the package and the operational principle of control chip UC3854 is also introduced. By simulation, compared with positive PFC, the property of the active PFC circuit is improved, in which the THD reduces from 25.2% to 9.3%, the PF value increases from 0.9697 to 0.9957, and the output voltage fluctuation is reduced. This thesis mainly focuses on the design of a APFC circuit with output power of 250W using UC3854, in which Cree's SiC SBD CSD10060 is used instead of Si FRED in the market. With Pspice simulation, the THD reduces from 9.3% to 4.8%, the PF value increases from 0.9957 to 0.9988, the power loses of the diode is reduced about 1~2W and the switching losses is reduced about 8W due to the good inverse recovery characteristic of SiC SBD. Finally the output is increased about 10W, so the power density is enhanced.