Systems and methods for two-level protection of power conversion systems

摘要

Systems and methods are provided for protecting a power conversion system. A system controller includes a two-level protection component and a driving component. The two-level protection component is configured to detect an output power of a power conversion system and generate a protection signal based on at least information associated with the output power. The driving component is configured to generate a drive signal based on at least information associated with the protection signal and output the drive signal to a switch associated with a primary current flowing through a primary winding of the power conversion system. The driving component is further configured to generate the drive signal corresponding to a first switching frequency to generate the output power equal to a first power threshold and generate the drive signal corresponding to a second switching frequency to generate the output power equal to a second power threshold.

主权项

1. A system controller for protecting a power conversion system, the system controller comprising:
a two-level protection component configured to detect an output power of a power conversion system and generate a protection signal based on at least information associated with the output power of the power conversion system; and a driving component configured to generate a drive signal based on at least information associated with the protection signal and output the drive signal to a switch associated with a primary current flowing through a primary winding of the power conversion system; wherein the driving component is further configured to:
generate the drive signal corresponding to a first switching frequency to generate the output power equal to a first power threshold; andgenerate the drive signal corresponding to a second switching frequency to generate the output power equal to a second power threshold, the second power threshold being larger than the first power threshold, the second switching frequency being larger than the first switching frequency; wherein the two-level protection component is further configured to:
in response to the output power being equal to or larger than the first power threshold for a first predetermined period of time, generate the protection signal to cause the switch to open and remain open to protect the power conversion system; andin response to the output power being equal to or larger than the second power threshold for a second predetermined period of time, generate the protection signal to cause the switch to open and remain open to protect the power conversion system, the second predetermined period of time being shorter than the first predetermined period of time.