Bridgeless power factor correction circuit

A bridgeless power factor correction (PFC) circuit, comprising:

• a low-frequency bridge leg, a three-port network, a lightning and surge protection bridge leg and a capacitor, wherein
• the low-frequency bridge leg comprises two diodes connected in series:
• a first diode and a second diode;
• the three-port network comprises a switch tube and an inductor;
• the low-frequency bridge leg and the three-port network act together to realize PFC;
• the lightning and surge protection bridge leg comprises two diodes connected in series:
• a third diode and a fourth diode;
• the capacitor is connected between both terminals of the low-frequency bridge leg, and between both terminals of the lightning and surge protection bridge leg;
• a common terminal of the first and second diodes is connected to a terminal of an AC power, and a common terminal of the third and fourth diodes is connected to the other terminal of the AC power;
• the three-port network has a first port and a second port with the capacitor connected therebetween, and a third port connected to the common terminal of the third and fourth diodes.