Abstract: The embodiments of the present disclosure provide an imaging system, including: a scanning cabin management module configured to manage at least one scanning cabin, wherein each of the at least one scanning cabin is configured to place a subject; an imaging module configured to perform a scanning on the subject in the scanning cabin; and a control module configured to control the scanning cabin management module and/or the imaging module.

Abstract: In a power factor correction PFC circuit control method and a PFC circuit, a control module determines that an alternating current on a single-phase input/output terminal is in a positive half cycle. The control module turns on or turns off switching transistors on the first bridge arm and the second bridge arm, to boost a first voltage at a first parallel connection point. The control module turns on a switching transistor on the third bridge arm when determining that the first voltage is equal to a voltage of a positive bus of the direct current module. A switching loss of the PFC circuit can be effectively reduced, and performance of the PFC circuit can be improved.

Abstract: A free-wheeling diode control method includes determining whether a sum of a first pulse width value of a free-wheeling diode obtained according to an inductance current law and a third pulse width value of a main control tube meets a first preset condition, obtaining a determining result, and controlling, according to the determining result, conduction of the free-wheeling diode according to the first pulse width value or a second pulse width value of the free-wheeling diode obtained according to a volt-second balance law.

Abstract: A free-wheeling diode control method includes determining whether a sum of a first pulse width value of a free-wheeling diode obtained according to an inductance current law and a third pulse width value of a main control tube meets a first preset condition, obtaining a determining result, and controlling, according to the determining result, conduction of the free-wheeling diode according to the first pulse width value or a second pulse width value of the free-wheeling diode obtained according to a volt-second balance law.