| CPC H02M 3/33571 (2021.05) [H02M 1/0025 (2021.05); H02M 1/0048 (2021.05); H02M 1/0058 (2021.05); H02M 1/08 (2013.01); H02M 1/342 (2021.05); H02M 1/38 (2013.01); H02M 3/01 (2021.05); H02M 3/33507 (2013.01); H02M 3/33515 (2013.01); H02M 3/33523 (2013.01)] | 19 Claims |
|
1. A converter, comprising:
a direct current power supply;
a main power transistor;
an auxiliary power transistor
a first capacitor
a transformer
a control circuit; and
wherein:
the first capacitor and the transformer are connected in series to form a series circuit, the series circuit is connected to a first terminal and a second terminal of the auxiliary power transistor in parallel, a first terminal of the main power transistor is connected to the second terminal of the auxiliary power transistor, a second terminal of the main power transistor is connected to one of a positive electrode or a negative electrode of the direct current power supply, the first terminal of the auxiliary power transistor is connected to the other electrode of the direct current power supply, and the negative electrode is grounded; and
the control circuit is configured to:
when the main power transistor is in a cutoff state and a target voltage reaches a target valley voltage, control the main power transistor to be conducted, wherein the target voltage is a voltage between the first terminal of the main power transistor and the ground, and the target valley voltage is a voltage of at least one waveform valley in the target voltage when the converter operates;
detect an excitation current in the transformer when the excitation current in the transformer is discontinuous and the auxiliary power transistor is conducted; and
when the excitation current is equal to 0, control the auxiliary power transistor to be cut off.
|