Double-transistor forward converter with wide input voltage and high dynamic response

A forward converter, high dynamic technology, applied in the direction of converting DC power input to DC power output, output power conversion device, adjusting electrical variables, etc., can solve problems such as system instability, damage, and winding occupying a large space. , to achieve high dynamic response characteristics, reduce coil loss, and improve reliability.

Active Publication Date: 2021-02-05
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the existing method of switching the transformer turns ratio, the transformer windings are selectively used, and the unused windings will occupy a large space, and the advantages of all windings cannot be exerted; and the network voltage detection circuit is usually placed in the switching power supply The input terminal is easily damaged by the impact of grid voltage spikes; the increase of the turn ratio will also make the crossover frequency move to a higher place, in order not to cause the crossover frequency of the converter to move to a higher point in the high turn ratio operation mode. The system is unstable, and the crossover frequency of the converter in the low turn ratio working mode is usually set at a low point, which makes it impossible for the converter to have high dynamic response characteristics in both high and low turn ratio working modes

Method used

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  • Double-transistor forward converter with wide input voltage and high dynamic response
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  • Double-transistor forward converter with wide input voltage and high dynamic response

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Embodiment 1

[0024] Overall structure of the present invention and overall working process of embodiment 1

[0025] Such as figure 1 As shown, a double-transistor forward converter with wide input voltage and high dynamic response according to the present invention consists of main switches S1 and S2, diodes D1 and D2 for magnetic reset, current sampling resistor R1, transformer T, Double pole double throw relay K, output rectification filter circuit F, current limiting resistor R2, rectifier diode D3, auxiliary power supply circuit D, control circuit Ctrl, switching circuit C and feedback circuit Fb.

[0026]The on-off of the main switches S1 and S2 is controlled by the control circuit Ctrl. When the main switches S1 and S2 are turned on, the input voltage Vin is transformed by the transformer T, and the output voltage of the transformer T is smoothed by the output rectification filter circuit F to obtain the output voltage. Vout, the load Load is powered; when the main switches S1 and S...

Embodiment 2

[0029] Embodiment 2 The specific structure and working principle of the switching circuit C of the present invention

[0030] Such as figure 2 As shown, the switching circuit C includes a Zener diode VD, resistors R3-R6, switching tubes S3-S5 and a capacitor C1, figure 2 K in is the double-pole double-throw relay K described in Embodiment 1. The DC voltage Vns3 is generated by the auxiliary power supply winding Ns3 and the auxiliary power supply circuit D, which indirectly reflects the size of the input network voltage Vin and then affects the switching circuit C to control the double-pole double-throw relay K to change the series-parallel connection of the secondary windings Ns1 and Ns2, The purpose of changing the turn ratio of the transformer T to adapt to the input voltage Vin is achieved.

[0031] When the input voltage Vin is high (220V), Vns3 is also high, the Zener diode VD is turned on, and the DC voltage Vns3 minus the conduction voltage drop of the Zener diode V...

Embodiment 3

[0033] Embodiment 3 The specific structure and working principle of the feedback circuit Fb of the present invention

[0034] Such as image 3 As shown, the feedback circuit Fb includes resistors R7-R14, capacitors C2 and C3, optocouplers OC1 and OC2, and error amplifier U1, and S3 in the figure is the switch tube S3 described in Embodiment 2.

[0035] The voltage dividing resistors R12 and R14 divide the output voltage Vout of the output rectification and filtering circuit F, and then the error amplifier U1 amplifies the error voltage, and the amplified error voltage passes the error voltage to the optical through the resistors R8 and R9 and the optocouplers OC1 and OC2. Coupled output terminal Vfb, and then the error voltage is fed back to the control circuit Ctrl.

[0036] When the input terminals of the optocouplers OC1 and OC2 are not conducting, the resistors R10 and R13 provide an operating current to the error amplifier U1 to ensure that the error amplifier U1 can sta...

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PUM

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Abstract

A double-tube forward converter with wide input voltage and high dynamic response, belonging to the technical field of switching power supplies, comprises a transformer T, an output rectifying and filtering circuit F, an auxiliary power supply circuit D, a control circuit Ctrl, a double-pole double-throw relay K, a switching circuit C and a feedback circuit Fb. According to the invention, wide voltage input of the double-tube forward converter is achieved through a transformer turn ratio switching method, the high dynamic response characteristic is achieved in the high turn ratio working modeand the low turn ratio working mode, the auxiliary power supply winding Ns3 is used for indirectly detecting the network voltage, and the reliability of the network voltage detection circuit is improved.

Description

technical field [0001] The invention belongs to the technical field of switching power supplies, and in particular relates to a double-tube forward converter with wide input voltage and high dynamic response. Background technique [0002] Among the numerous isolated switching power supply topologies, the dual-transistor forward topology is widely used in environments with high reliability requirements due to its excellent stability and safety, such as computers, aviation equipment, medical equipment, etc. environment. [0003] At present, there are two AC grid voltages in the world, namely AC 110V and AC 220V. In order to be compatible with the two grid voltages and consider grid voltage fluctuations, switching power supplies are usually designed to have a full voltage input range (AC 90V ~ AC 264V). However, due to the shortcoming of the traditional dual-transistor forward converter whose duty ratio cannot be greater than 0.5, it is difficult for this type of converter to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M3/335
CPCH02M3/33569
Inventor 索辉许泷潇杨罕
Owner JILIN UNIV
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