CN101552452B - Short-circuit protection circuit for switching power supply of frequency converter - Google Patents

Short-circuit protection circuit for switching power supply of frequency converter Download PDF

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Publication number
CN101552452B
CN101552452B CN2009100456780A CN200910045678A CN101552452B CN 101552452 B CN101552452 B CN 101552452B CN 2009100456780 A CN2009100456780 A CN 2009100456780A CN 200910045678 A CN200910045678 A CN 200910045678A CN 101552452 B CN101552452 B CN 101552452B
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circuit
connects
capacitor
resistance
short
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CN101552452A (en
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徐勇
金辛海
蔡新波
成爱军
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Shanghai Step Electric Corp
Shanghai Sigriner Step Electric Co Ltd
Shanghai Step Electric Co Ltd
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Shanghai Step Electric Corp
Shanghai Sigriner Step Electric Co Ltd
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Abstract

The invention relates to a short-circuit protection circuit for switching power supply of a frequency converter, comprising a main power circuit. The main power circuit is respectively connected to anRCD absorbing circuit, a PWM controller and an output rectification circuit. A feedback circuit is respectively connected with the PWM controller and the output rectification circuit. The short-circu it protection circuit further comprises an overvoltage protection circuit connected with the PWM controller and the feedback circuit. In the +5V rectification output circuit of the output rectification circuit, a restorable fuse is serially connected between a 5V rectifier diode and a resistor. The beneficial effects of the invention are that the invention protects the output of any circuit and has perfect protection function; when short circuit appears, on-the-job accident of the frequency converter is not caused and failure of elements is not caused.

Description

The short-circuit protection circuit of switching power supply of frequency converter
Technical field
The present invention relates to a kind of switching power supply of frequency converter, relate in particular to the short-circuit protection circuit of this switching power supply of frequency converter.
Background technology
By Fig. 1, Fig. 2 as seen: the operation principle of the short-circuit protection circuit of existing switching power supply of frequency converter is as follows: when ± 15V; + 24V; when being short-circuited with the IGBT driving power of four tunnel+25V; feedback voltage+V5F is far below 5V; the full duty ratio output of PWM chip; because the short-circuited winding output current sharply increases, and has consumed most energy that the former limit of transformer provides, the voltage of other windings also all descends.Because the PWM chip operation needs the operating current about 10mA; by adjusting the resistance of R5; can be so that auxiliary winding voltage VCC reduce under the minimum voltage of PWM chip operation, Switching Power Supply enters and restarts the stage then, and dc bus charges to C4 by R1; when VCC rises to the starting resistor of chip of PWM; Switching Power Supply work if this moment, short circuit in winding was not removed, then repeats above-mentioned process; VCC voltage descends once more, thereby has realized " having the hiccups " protection.By adjusting the resistance of R5, can realize ± 15V+24V, " having the hiccups " protection of He Silu+25V; By adjusting the value of R1 and C4, the fall time of VCC in the time of can adjusting start-up time of Switching Power Supply and short-circuit protection and take place is not even short circuit so always can cause burning out of components and parts yet.Wherein: the PWM controller is by pwm chip U1, and resistance R 4 and capacitor C 3 are formed; Main power circuit is instead swashed high frequency transformer T1 and sampling resistor R8 and is formed by metal-oxide-semiconductor M1; RCD absorbs circuit D2, and R2 and C1 form; Feedback circuit comprises optocoupler TLP781, accurate voltage-stabiliser tube TL431 and R9, and R10, R12, R14, R15, C6 and C7 form; Output rectification circuit, output voltage+5V and a tunnel+24V exports expression with feedback; + 5V rectifying output circuit comprises rectifier diode D5V, rectifying and wave-filtering capacitor C 5V; + 24V output comprises rectifier diode D24V, dc filter capacitor C24V.
But there is following defective in above-mentioned line construction: when+when 5V was short-circuited ,+5V out-put supply was only exported low voltage (about 3V), did not far reach feedback voltage (5V), the full duty ratio output of PWM chip this moment, and intake increases.Because this road output voltage is lower, though be short-circuited, the energy that consumes is less than the energy that causes owing to the full duty ratio of PWM increasing, thereby the output voltage on other each roads all has rising, can not realize " having the hiccups " protection.The consequence that causes is as follows: the rectifier diode of+5V output can be burnt out, and the IGBT driving voltage of+25V rises and causes acting on the grid level on the IGBT and the voltage V of source electrode GERise, may cause the damage of IGBT; ± 15V and+rising of 24V voltage may cause failure of elements such as chip.
Summary of the invention
The technical issues that need to address of the present invention have provided a kind of short-circuit protection circuit of switching power supply of frequency converter, are intended to solve the above problems.
In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions:
The present invention includes: main power circuit; Described main power circuit connects RCD respectively and absorbs circuit, PWM controller and output rectification circuit; A feedback circuit connects PWM controller, output rectification circuit respectively; An overvoltage crowbar; Described overvoltage crowbar connects PWM controller and feedback circuit; Described output rectification circuit+the 5V rectifying output circuit in, between rectifier diode and resistance the serial connection one can recover fuse.
Compared with prior art, the invention has the beneficial effects as follows: can realize that the protection of any one tunnel output is had perfect defencive function; When short circuit takes place, can not cause the frequency converter operating accident, can not cause failure of elements yet.
Description of drawings
The module map of switching power supply of frequency converter in Fig. 1 prior art.
Fig. 2 is the concrete line map of switching power supply of frequency converter in the prior art;
Fig. 3 is a module map of the present invention;
Fig. 4 is a concrete line map of the present invention;
Embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail:
By Fig. 3, Fig. 4 as seen: the present invention includes: main power circuit; Described main power circuit connects RCD respectively and absorbs circuit, PWM controller and output rectification circuit; A feedback circuit connects PWM controller, output rectification circuit respectively; Also comprise: an overvoltage crowbar; Described overvoltage crowbar connects PWM controller and feedback circuit; Described output rectification circuit+the 5V rectifying output circuit in, between rectifier diode D5V and resistance the serial connection one can recover fuse F1;
Described overvoltage crowbar comprises: the positive pole of diode D4 connects the COMP end of PWM controller, and the negative pole of diode D4 connects by resistance R 11 and capacitor C 5 and the end that connects; The negative pole of diode D4 also connects the base stage of PNP transistor Q1, the collector electrode of NPN transistor Q2 and an end of capacitor C 9; Resistance R 11 and capacitor C 5 and the other end that connects are connected the emitter of PNP transistor Q1 and the node of resistance R 13 and capacitor C 8; The collector electrode of PNP transistor Q1 connects the base stage of the other end, the NPN transistor Q2 of capacitor C 8, by the positive pole of resistance R 16 and capacitor C 10 and an end that connects and voltage-stabiliser tube Z1; Negative pole and the VCC of the other end of resistance R 13 and voltage-stabiliser tube Z1 join; The grounded emitter of the other end of capacitor C 9 and NPN transistor Q2; Resistance R 16 and capacitor C 10 and the other end ground connection that connects.
PNP transistor Q1 in the overvoltage crowbar and NPN transistor Q2 such as Fig. 4 form the regenerative circuit of similar thyristor operation principle, when VCC voltage during greater than the burning voltage of voltage-stabiliser tube Z1, the Z1 conducting, trigger NPN diode Q2 conducting, Q1, Q2 are owing to the rapid conducting of positive feedback, and the negative electrode of D4 is clamped to low level; R16 and C10 play filter action, prevent owing to disturb the generation false triggering.
The present invention has designed on circuit and can recover fuse F1 and overvoltage crowbar (by D4, Z1, Q1, Q2, R11, R13, R16, C5, C8, C9, C10 composition).When+5V is short-circuited instantaneous; can recover fuse F1 has an effect; being equivalent to load disconnects; and short circuit is instantaneous; electric weight on the capacitor C 5V descends; the output voltage of+5VF reduces, feedback neutralization, the full duty ratio output of PWM chip; this moment, auxiliary winding VCC voltage rose; when voltage rose to the safe voltage of voltage-stabiliser tube Z1 setting, overvoltage crowbar was triggered, Q1; Q2 conducting (the similar silicon controlled operation principle of the principle of overvoltage protection; Q1 and Q2 form regenerative circuit, in case after the conducting, even triggering signal disappears; Q1 and Q2 still keep conducting); the voltage of VCC is dragged down, and the voltage of 1 pin by the clamped saturation conduction pressure drop VCE to Q2 of diode D4, do not work by Switching Power Supply yet.Has only after re-powering Switching Power Supply task again.
Operation principle of the present invention is as follows:
When ± 15V ,+24V is when the IGBT driving power of He Silu+25V is short-circuited, feedback voltage+V5F is far below 5V, and the full duty ratio output of PWM chip is because the short-circuited winding output current sharply increases, consumed most energy that the former limit of transformer provides, the voltage of other windings also all descends.Because the PWM chip operation needs the operating current about 10mA; by adjusting the resistance of R5; can be so that auxiliary winding voltage VCC reduce under the minimum voltage of PWM chip operation, Switching Power Supply enters and restarts the stage then, and dc bus charges to C4 by R1; when VCC rises to the starting resistor of chip of PWM; Switching Power Supply work if this moment, short circuit in winding was not removed, then repeats above-mentioned process; VCC voltage descends once more, thereby has realized " having the hiccups " protection.By adjusting the resistance of R5, can realize ± 15V+24V, " having the hiccups " protection of He Silu+25V; By adjusting the value of R1 and C4, the fall time of VCC in the time of can adjusting start-up time of Switching Power Supply and short-circuit protection and take place is not even short circuit so always can cause burning out of components and parts yet.
When+when 5V was short-circuited ,+5V out-put supply was only exported about 3V, did not far reach feedback voltage (5V), the full duty ratio output of PWM chip this moment, and intake increases.Because this road output voltage is lower, though be short-circuited, the energy that consumes is less than the energy that causes owing to the full duty ratio of PWM increasing, thereby the output voltage on other each roads all has rising, can not realize " having the hiccups " protection.The consequence that causes is as follows: the rectifier diode of+5V output can be burnt out, and the IGBT driving voltage of+25V rises and causes acting on the voltage VGH rising of grid and source electrode on the IGBT, may cause the damage of IGBT; ± 15V and+rising of 24V voltage may cause failure of elements such as chip.For this reason, on circuit, designed and to have recovered fuse F1 and overvoltage crowbar; When+5V is short-circuited instantaneous; can recover fuse F1 has an effect; being equivalent to load disconnects; and short circuit is instantaneous; electric weight on the capacitor C 5V descends; the output voltage of+5VF reduces, feedback neutralization, the full duty ratio output of PWM chip; this moment, auxiliary winding VCC voltage rose; when voltage rose to the safe voltage of voltage-stabiliser tube Z1 setting, overvoltage crowbar was triggered, Q1; Q2 conducting (the similar silicon controlled operation principle of the principle of overvoltage protection; Q1 and Q2 form regenerative circuit, in case after the conducting, even triggering signal disappears; Q1 and Q2 still keep conducting); the voltage of VCC is dragged down, and the voltage of 1 pin by the clamped saturation conduction pressure drop VCE to Q2 of diode D4, do not work by Switching Power Supply yet.Has only after re-powering Switching Power Supply task again.

Claims (1)

1. the short-circuit protection circuit of a switching power supply of frequency converter comprises: main power circuit; Described main power circuit connects RCD respectively and absorbs circuit, PWM controller and output rectification circuit; A feedback circuit connects PWM controller, output rectification circuit respectively; It is characterized in that also comprising: an overvoltage crowbar; Described overvoltage crowbar connects PWM controller and feedback circuit; Described output rectification circuit+the 5V rectifying output circuit in, between rectifier diode D5V and resistance the serial connection one can recover fuse; Described overvoltage crowbar comprises: the positive pole of diode D4 connects the COMP end of PWM controller, and the negative pole of diode D4 connects by resistance R 11 and capacitor C 5 and the end that connects; The negative pole of diode D4 also connects the base stage of PNP transistor Q1, the collector electrode of NPN transistor Q2 and an end of capacitor C 9; Resistance R 11 and capacitor C 5 and the other end that connects are connected the emitter of PNP transistor Q1 and the node of resistance R 13 and capacitor C 8; The collector electrode of PNP transistor Q1 connects the base stage of the other end, the NPN transistor Q2 of capacitor C 8, by the positive pole of resistance R 16 and capacitor C 10 and an end that connects and voltage-stabiliser tube Z1; Negative pole and the VCC of the other end of resistance R 13 and voltage-stabiliser tube Z1 join; The grounded emitter of the other end of capacitor C 9 and NPN transistor Q2; Resistance R 16 and capacitor C 10 and the other end ground connection that connects.
CN2009100456780A 2009-01-16 2009-01-16 Short-circuit protection circuit for switching power supply of frequency converter Active CN101552452B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2009100456780A CN101552452B (en) 2009-01-16 2009-01-16 Short-circuit protection circuit for switching power supply of frequency converter

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Application Number Priority Date Filing Date Title
CN2009100456780A CN101552452B (en) 2009-01-16 2009-01-16 Short-circuit protection circuit for switching power supply of frequency converter

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CN101552452A CN101552452A (en) 2009-10-07
CN101552452B true CN101552452B (en) 2011-05-25

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Publication number Priority date Publication date Assignee Title
CN103187711B (en) * 2013-04-18 2015-05-20 山东五洲电气股份有限公司 Automatic overvoltage protection circuit for switching power supply
CN103474965A (en) * 2013-08-27 2013-12-25 崧顺电子(深圳)有限公司 Low-cost alternating-current input overvoltage protection circuit and switching power supply
CN105990819B (en) * 2015-01-29 2018-10-02 宝山钢铁股份有限公司 The DC voltage detection of low voltage frequency converter and protection circuit
CN105430813B (en) * 2015-12-29 2018-03-02 横店集团得邦照明股份有限公司 It is a kind of to be applied to protection circuit and implementation method with damping phase-cut dimming circuit
CN112688277B (en) * 2021-01-08 2023-03-10 四川湖山电器股份有限公司 Switching power supply overcurrent protection detection device and switching power supply

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