An asymmetrical half-bridge flyback converter, wherein the asymmetrical half-bridge flyback converter comprises a first power transistor (101, Q L), a second power transistor (102, Q H), a primary-side resonant capacitor (103, C rp), a transformer, a third power transistor (105, Q 1), a secondary-side resonant capacitor (106, C rs), an excitation inductor (L m) and a transformer leakage inductor (L r); the first power transistor (101, Q L) and the second power transistor (102, Q H) are coupled to two terminals of a direct current power supply (V in) after being connected in series; the primary-side resonant capacitor (103, C rp) is connected between a terminal of the first power transistor (101, Q L) being connected to a terminal of the direct current power supply (V in) and the transformer leakage inductor (L r); the excitation inductor (L m) is connected between the transformer leakage inductor (L r), a terminal of the first power transistor (101, Q L) not being connected to a terminal of the direct current power supply (V in) and a terminal of the second power transistor (102, Q H) not being connected to a terminal of the direct current power supply (V in); and a primary side of the transformer is connected in parallel to two terminals of the first power transistor through the primary-side resonant capacitor (103, C rp), and a secondary side of the transformer is coupled to the third power transistor (105, Q 1) and the secondary-side resonant capacitor (106, C rs); and wherein when the first power transistor (101, Q L) is turned on, the primary-side resonant capacitor (103, C rp), the secondary-side resonant capacitor (106, C rs), and the transformer leakage inductor (L r) all participate in resonance, and the resonance is hybrid resonance; and a parameter of the hybrid resonance is adjusted, to reduce a root mean square value of a current flowing through the third power transistor (105, Qi); and characterised in that: the adjustment of the parameter of the hybrid resonance comprises adjusting initial state values of the hybrid resonance; the asymmetrical half-bridge flyback converter further comprises a second capacitor (C b), and the second capacitor (C b) is connected in parallel to the third power transistor (105, Qi); and the second capacitor (C b) is configured to adjust the initial state values of the hybrid resonance. the first power transistor (101, Q L) and the second power transistor (102, Q H) are coupled to two terminals of a direct current power supply (V in) after being connected in series; the primary-side resonant capacitor (103, C rp) is connected between a terminal of the first power transistor (101, Q L) being connected to a terminal of the direct current power supply (V in) and the transformer leakage inductor (L r); the excitation inductor (L m) is connected between the transformer leakage inductor (L r), a terminal of the first power transistor (101, Q L) not being connected to a terminal of the direct current power supply (V in) and a terminal of the second power transistor (102, Q H) not being connected to a terminal of the direct current power supply (V in); and a primary side of the transformer is connected in parallel to two terminals of the first power transistor through the primary-side resonant capacitor (103, C rp), and a secondary side of the transformer is coupled to the third power transistor (105, Q 1) and the secondary-side resonant capacitor (106, C rs); and wherein when the first power transistor (101, Q L) is turned on, the primary-side resonant capacitor (103, C rp), the secondary-side resonant capacitor (106, C rs), and the transformer leakage inductor (L r) all participate in resonance, and the resonance is hybrid resonance; and a parameter of the hybrid resonance is adjusted, to reduce a root mean square value of a current flowing through the third power transistor (105, Qi); and characterised in that: the adjustment of the parameter of the hybrid resonance comprises adjusting initial state values of the hybrid resonance; the asymmetrical half-bridge flyback converter further comprises a second capacitor (C b), and the second capacitor (C b) is connected in parallel to the third power transistor (105, Qi); and the second capacitor (C b) is configured to adjust the initial state values of the hybrid resonance. the adjustment of the parameter of the hybrid resonance comprises adjusting initial state values of the hybrid resonance; the asymmetrical half-bridge flyback converter further comprises a second capacitor (C b), and the second capacitor (C b) is connected in parallel to the third power transistor (105, Qi); and the second capacitor (C b) is configured to adjust the initial state values of the hybrid resonance.