Switching circuit for switching power supply control modes and control method for switching circuit

Abstract

The invention discloses a switching circuit for switching power supply control modes and a control method for the switching circuit. The switching circuit for the switching power supply control modes comprises a digital signal processor (DSP) circuit, an output voltage and current feedback circuit, a pulse width modulation (PWM) driving switching circuit, a PWM driving circuit and a full-bridge power circuit, wherein the DSP circuit is connected with the output voltage and current feedback circuit, the PWM driving switching circuit and the PWM driving circuit respectively; the full-bridge power circuit is connected with the output voltage and current feedback circuit and the PWM driving circuit respectively; and the PWM driving switching circuit is also connected with the PWM driving circuit. When the full-bridge power circuit is electrified to work, a bipolar control mode is adopted, and the DSP circuit judges whether the bipolar control mode or a finite bipolar control mode is adopted according to output power. According to the control method, the two control modes are switched, so that the problem of great loss under the finite bipolar control mode when the full-bridge power circuit is lightly loaded and unloaded is solved.

Description

technical field [0001] The invention relates to the technical field of a high-frequency switching power supply, in particular to a switching circuit of a switching power supply control mode and a control method thereof. Background technique [0002] When the voltage and current ratings of the power switch tubes are the same, the output power of the converter is usually proportional to the number of power switch tubes used. Therefore, at present, in the application of medium and high-power DC power supplies, full-bridge converters are usually used. Full-bridge converters Including full bridge inverter and output rectification filter circuit. The limited bipolar control method is a widely used control method for full-bridge converters to realize soft switching. It has the advantages of wide soft switching range and high efficiency, especially in welding and some electrochemical industries. However, this control The method is that the loss is extremely serious at no-load and l...

AI Technical Summary

Problems solved by technology

The limited bipolar control method is a widely used control method for full-bridge converters to realize soft switching. It has the advantages of wide soft switching range and high efficiency, especially in welding and some electrochemical industries. However, this control Method The loss is extremely serious at no-load and light load. In some applications, the no-load and light-load loss is even greater than full load. Even by increasing the commutation inductance, it is difficult to solve the problem of no-load loss

Images