Leakage inductance energy absorption and feedback circuit of flyback transformer and control method thereof

Abstract

The invention discloses a leakage inductance energy absorption and feedback circuit of a flyback transformer and a control method thereof. The leakage inductance energy absorption and feedback circuit is integrated together and formed by a clamper tube Sc and a clamper capacitor Cc only. The leakage inductance energy absorption and feedback circuit is simple and reliable in structure. According to the control method of the leakage inductance energy absorption and feedback circuit, the clamper tube is switched on for Tc after a flyback main tube is switched off, and Tc is half of a resonance period of leakage inductance and the clamper capacitor and far shorter than the switch-off time of the main tube. The leakage inductance energy absorbed by the clamper capacitor is released to a main power circuit by means of the resonance of the clamper capacitor and the leakage inductance, so that the switched-off voltage peak of the flyback circuit main tube is lowered effectively, and the efficiency of the flyback transformer is increased. Meanwhile, by means of non-complementary connection of the clamper tube and the main tube, the switch-on time of the clamper tube is far shorter than the switch-off time of the main tube, and therefore, the absorption and feedback circuit does not affect the switching process of the main tube and is suitable for flyback circuits in any operation modes. The circuit reliability and efficiency of a miniature photovoltaic grid-connected inverter utilizing the leakage inductance energy absorption and feedback circuit can be increased greatly.

Description

technical field [0001] The invention relates to an absorption and feedback circuit of leakage inductance energy of a flyback transformer in the field of photovoltaic grid-connected power generation and a control method thereof. Background technique [0002] The micro grid-connected photovoltaic inverter improves the power generation efficiency of the system under the conditions of photovoltaic module power mismatch and shadow, and at the same time has the advantages of safety and module-level monitoring. It has been obtained in the household photovoltaic grid-connected system application of photovoltaics. [0003] Micro grid-connected photovoltaic inverters are generally installed on the bracket under the module, or directly on the frame of the module. Maintenance is extremely troublesome, so it needs to have the same lifespan and reliability as the module. In addition, since the micro-inverter operates outdoors, the ambient temperature can reach up to 65°C. For reliability...

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Problems solved by technology

[0008] The present invention is suitable for flyback circuits in continuous, discontinuous and critical discontinuous operating modes, and solves the problems of the current critical discontinu

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