Single-circuit output flyback converter controlled in current mode

Abstract

The invention relates to a single-circuit output flyback converter controlled in a current mode. The single-circuit output flyback converter comprises an alternating current input source, wherein the alternating current input source inputs direct current to a first buffer circuit through an input filter capacitor after passing through a rectifier bridge circuit; the first buffer circuit is connected in parallel to a primary winding of a transformer, the primary winding is connected with the drain electrode of a switching tube, and a secondary winding is respectively connected with an output rectifier diode and the input end of a first absorption circuit and is connected to a control chip through a chip power supply circuit; the output end of the output rectifier diode is connected to a three-terminal voltage-stabilizing circuit through an output filter capacitor after being connected in parallel with the output end of the first absorption circuit; a second buffer circuit is connected in parallel between the source electrode and the drain electrode of the switching tube, and the grid electrode and the source electrode are respectively connected with the control chip through a sampling resistor; the compensation end of the control chip is connected with the output end of an isolating circuit, the input end of the insolating circuit is connected in parallel with the output filter capacitor, and the other input end of the isolating circuit is connected with the three-terminal voltage-stabilizing circuit which outputs voltage-stabilizing direct current; and a second absorption circuit is arranged in the three-terminal voltage-stabilizing circuit.

Description

technical field [0001] The invention relates to a flyback converter, in particular to a single output flyback converter used for current mode control in the field of switching power supplies. Background technique [0002] At present, in the fields of DC motor speed regulation, battery charging, switching power supply, etc., especially in electric traction, electric vehicles such as subways, urban light rails, electric locomotives, trolleybuses, battery cars, and electric forklifts used to use rheostats to realize electric power. The starting, speed regulation and braking of the car have problems such as high power consumption, low efficiency, stepped speed regulation, and poor running stability. After the introduction of DC chopper, electric vehicles are powered by constant DC power supply (such as battery, uncontrolled rectifier power supply), which can conveniently realize stepless speed regulation and stable operation, and more importantly, save electricity by 20% compare...

AI Technical Summary

Problems solved by technology

However, the use of a linear power supply requires a huge and heavy transformer, and the volume and weight of the filter capacitor required are also quite large, and the voltage feedback circuit works in a linear state, and there is a certain voltage drop on the regulator tube. When outputting a large operating current It will cause the power consumption of the adjustment tube to be too large, the conversion efficiency is low, and a large heat sink must be installed

The switching power supply has the advantages of small size, light weight, simple circuit structure, wide output voltage range, and modularization, but the traditional switching power supply still has the problems of poor commutation effect and low power quality, such as grid operating power Low factor, high switching loss and on-state loss, large transformer leakage inductance and easy to produce intermittent oscillation, low switching frequency, large ripple, insufficient precision of voltage and current stabilization, many harmonic components, poor anti-electromagnetic interference ability and Problems such as high-frequency noise of the transformer

In addition, BUCK, BOOST, BUCK-BOOST, CUK, SPEIC, ZETA and other non-isolated switching power supplies have poor anti-interference performance and poor load characteristics

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