SIC Power Device Characteristics And Its Application In PFC Circuits

According to Moore's Law,the Si power devices which are used on a large scale at present have gradually approached the development limit,and cannot satisfy the higher demands for device operating frequency,tolerable temperature,power,energy efficiency,resistance to harsh environments,portability and miniaturization raised for the future social development.It has been conducted to look for new-material semi-conductor power devices which are more consistent with the future development and replace the semi-conductor Si-material power devices early in the 1990s.the third-generation semi-conductor materials which are represented by Sic have gradually won the attention from the industry insiders by virtue of various excellent properties.SiC power devices are characterized by small counter current,high switching frequency,high blocking voltage,small on-resistance,high operating temperature,etc.,and in the early of the 21st Century,Schottky barrier diode made from SiC material has been successfully used outside the lab and realized the commercialized scale.In the field of future power electronic technologies,the SiC-material power devices will gradually replace the Si-material power devices and have a vast application prospect.The dissertation analyzes the operating characteristics of SiC Schottky diode and SiC MOSFET,and also the differences with Si power devices,analyzes and discusses about the definition and calculation of power factor and the switching loss of Boost APFC circuit,and expounds on the characteristics of SiC Schottky diode CSD10060 and SiC MOSFET CMF10120D,the topology and control of various PFC technologies,and the encapsulation and operating principles of control chip UC3854.It designs and makes a 250W-output APFC circuit with the power-factor control chip UC3854,divides the combinations of different SiC power devices and Si power devices into four tested groups which are applied in the APFC circuit,analyzes the performance of the APFC circuit and the loss of semi-conductor power devices used in the circuit,and points out that SiC power devices can effectively lower the switching loss compared with Si power devices.It also completes making the double-pulse dynamic testing circuit,and tests the main characteristics and parameters of SiC power devices in an experiment.When the APFC circuit entirely uses SiC power devices rather than Si power devices,the THD factor decreases from 9.2%to 3.7%,and the power factor increases from 0.995 to 0.999,the loss of the diode decreases from 6.2 W to 1.9 W,and the loss of the switching MOSFET decreases from 22.8 W to 12.3 W.