A switching power supply and its control method

Abstract

The invention discloses a switch power supply and a control method of the switch power supply. The switch power supply is composed of a three-phase voltage type PWM rectifier and an H-bridge high-frequency DC / DC converter. Two additional inductance elements are introduced to the connecting middle point of a direct-current capacitor and the connecting middle point of a DC / DC converter bridge arm. The introduced additional inductance elements can provide an energy way for the transient state process of an electronic power switch of the DC / DC converter, and therefore the zero voltage switching-on and zero current switching-off of the electronic power switch are achieved. The active-disturbance-rejection control technology is adopted, and therefore stable control over the DC / DC converter can be effectively achieved, the number of switching-on and switching-off actions in the transient state process is lowered, and switching loss is reduced. By means of the switch power supply and the control method, the zero voltage switching-on and zero current switching-off of a lag bridge arm and the zero voltage switching-on and approximate zero current switching-off of an ahead bridge arm can be effectively and simultaneously achieved for the DC / DC converter under various load states, switching loss is reduced, and efficiency of the switch power supply is further improved.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a switching power supply and a control method thereof. Background technique [0002] With the development of power electronic devices, device topology and control technology, modern power electronic technology has become an important means and key factor for high efficiency, energy saving, traditional equipment transformation and industrial upgrading. In recent years, high-efficiency high-frequency switching power supplies for low-voltage fields have been developed successively at home and abroad. Switching power supply is a kind of power supply that uses modern power electronic technology to control the time ratio of semiconductor switching devices to turn on and off, and maintains a stable output voltage and current. Switching power supply is generally composed of a main circuit and a control circuit. The traditional electroplating electrolytic DC power supply mainly...

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Problems solved by technology

In order to achieve zero-voltage turn-on of the switch and zero-current turn-off at the same time, some literature proposes to use a secondary side energy recovery buffer circuit to reset the primary side current. The circuit structure is simple and has high engineering application value. However, the transformer needs to be The special design adds extra cost; there are also literatures that propose a full-bridge phase-shift pulse-width modulation DC / DC converter suitable for high-power arc welding, which introduces additional transformers and additional buffer circuits, which can realize the main work Zero-voltage turn-on and zero-current turn-off under no-load and short-circuit conditions, its topology is complex, and there is a circulating current

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