Abstract: A power expanding apparatus for three-phase LLC circuit is disclosed, which includes full-bridge switching networks, resonant networks, transformer networks, and rectifying networks. A primary side of a first transformer network is connected with an input voltage sequentially through a first resonant network and a first full-bridge switching network, a secondary side of the first transformer network is connected with a load through a first rectifying network; a primary side of a second transformer network is connected with the input voltage sequentially through a second resonant network and a second full-bridge switching network, and a secondary side of the second transformer network is connected with the load through a second rectifying network. Secondary sides of two transformer units in the first transformer network are in star-type connection with a secondary side of one transformer unit in the second transformer network.

Abstract: A power expanding apparatus for three-phase LLC circuit is disclosed, which includes full-bridge switching networks, resonant networks, transformer networks, and rectifying networks. A primary side of a first transformer network is connected with an input voltage sequentially through a first resonant network and a first full-bridge switching network, a secondary side of the first transformer network is connected with a load through a first rectifying network; a primary side of a second transformer network is connected with the input voltage sequentially through a second resonant network and a second full-bridge switching network, and a secondary side of the second transformer network is connected with the load through a second rectifying network. Secondary sides of two transformer units in the first transformer network are in star-type connection with a secondary side of one transformer unit in the second transformer network.

Abstract: Disclosed are an induction current sampling device and method for a bridgeless PFC circuit. The device includes a first sampling unit, a second sampling circuit and a third sampling circuit, wherein the first sampling unit, connected in serial with a first switch transistor of the bridgeless PFC circuit, is configured to sample a current flowing through the first switch transistor to acquire a first sampling signal V1; the the second sampling unit, connected in serial with a second switch transistor of the bridgeless PFC circuit, is configured to sample a current flowing through the second switch transistor to acquire a second sampling signal V2; and the third sampling unit, with one terminal connected with a ground of the bridgeless PFC circuit and the other terminal connected with a negative output of a PFC capacitor of the bridgeless PFC circuit, is configured to sample a current flowing through a boost diode of the bridgeless PFC circuit to acquire a third sampling signal V3.

Abstract: Disclosed are an induction current sampling device and method for a bridgeless PFC circuit. The device includes a first sampling unit, a second sampling circuit and a third sampling circuit, wherein the first sampling unit, connected in serial with a first switch transistor of the bridgeless PFC circuit, is configured to sample a current flowing through the first switch transistor to acquire a first sampling signal V1; the the second sampling unit, connected in serial with a second switch transistor of the bridgeless PFC circuit, is configured to sample a current flowing through the second switch transistor to acquire a second sampling signal V2; and the third sampling unit, with one terminal connected with a ground of the bridgeless PFC circuit and the other terminal connected with a negative output of a PFC capacitor of the bridgeless PFC circuit, is configured to sample a current flowing through a boost diode of the bridgeless PFC circuit to acquire a third sampling signal V3.

Abstract: A surge protection circuit includes a bridgeless boost sub-circuit and a surge protection sub-circuit. The bridgeless boost sub-circuit includes a first connection end and a second connection end of an alternating current power source, an inductor 1, an inductor 2, a switching tube 1 with a damping diode, a switching tube 2 with a damping diode, a capacitor, a diode 5, and a diode 6. The surge protection sub-circuit includes a first connection end and a second connection end of an alternating current power source, a diode 1, a diode 2, a transistor 3, a transistor 4, and a surge buffer device. In such a fashion, a surge buffer device is used to absorb a surge current, and the surge buffer device is not in a main topology circuit.