Abstract:
Disclosed is an anti-surge bridgeless power factor correction (PFC) circuit, which comprises a bridgeless PFC circuit and a boost capacitor which are connected between an AC power supply and a load in sequence. The anti-surge bridgeless PFC circuit also comprises a protection unit, a switch unit and a control unit. When a surge merges into the input of the AC power supply, the control unit controls the switch unit to be conducted, so as to form return current and discharge surge energy through the protection unit, the boost capacitor and the switch unit, thereby being able to protect a bridgeless PFC circuit from the influence of the surge.
Abstract:
A surge protection circuit comprises a bridgeless booster sub-circuit and a surge protection sub-circuit. The bridgeless booster sub-circuit comprises a first connecting end and a second connecting end of an alternating current power source, a first inductor (L1), a second inductor (L2), a first switching tube (VT1) with a damping diode, a second switching tube (VT2) with a damping diode, a capacitor (C1), a fifth diode (D5), and a sixth diode (D6). The surge protection sub-circuit comprises a first connecting end and a second connecting end of an alternating current power source, a first diode (D1), a second diode (D2), a third transistor (D3), a fourth transistor (D4), and a surge buffer device. The circuit uses a surge buffer device to absorb a surge current, and the surge buffer device is not in a main topology circuit.
Abstract:
A surge-proof bridge-free power factor correction (PFC) circuit, comprising: a bridge-free PFC circuit (15), a PFC output filter capacitor, a rectification unit (11), a surge absorption unit (12) and a reverse cutoff unit (13). When a surge occurs, the reverse cutoff unit (13) is in a cutoff state, so that the rectification unit (11) and the surge absorption unit (12) constitute an absorption loop, and the surge energy is absorbed by the surge absorption unit (12). The surge-proof bridge-free PFC circuit also comprises a discharge unit (14) which can release the energy absorbed by the surge absorption unit (12) when the surge occurs, and thus can protect a switch tube and a booster diode of the bridge-free PFC circuit, and can reduce the withstand voltage performance of a PFC output filter capacitor.
Abstract:
Disclosed are an apparatus and a method for sampling inductor current of a bridgeless PFC circuit. The apparatus comprises a first sampling unit, a second sampling unit, and a third sampling unit. The apparatus for sampling current of the bridgeless PFC circuit is connected to a bridgeless PFC circuit. The first sampling unit is connected in series to a first switch tube (S1) of the bridgeless PFC circuit, and is used for sampling current passing through the first switch tube (S1) to acquire a first sampled signal V1. The second sampling unit is connected in series to a second switch tube (S2) of the bridgeless PFC circuit, and is used for sampling current passing through the second switch tube (S2) to acquire a second sampled signal V2. One end of the third sampling unit is connected to a ground terminal of the bridgeless PFC circuit, the other end is connected to a negative output terminal of a PFC capacitor (C1) of the bridgeless PFC circuit, and is used for sampling current passing through a boost diode of the bridgeless PFC circuit to acquire a third sampled signal V3.