CN201260073Y - Protection circuit applied to inverter - Google Patents
Protection circuit applied to inverter Download PDFInfo
- Publication number
- CN201260073Y CN201260073Y CNU2008201717774U CN200820171777U CN201260073Y CN 201260073 Y CN201260073 Y CN 201260073Y CN U2008201717774 U CNU2008201717774 U CN U2008201717774U CN 200820171777 U CN200820171777 U CN 200820171777U CN 201260073 Y CN201260073 Y CN 201260073Y
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- inverter
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- voltage
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Abstract
The utility model discloses a protective circuit applied to an inverter, wherein, a voltage division circuit is respectively connected on two terminals of an output end of the inverter, each voltage division node of the voltage division circuit is connected with a voltage detection signal output end by a rectification circuit, and further feeds back voltage detection signals to the inverter, so as to judge whether to execute overvoltage protection. In the meanwhile, a synonymic end of a first secondary coil and a homonymic end of a second secondary coil of an inverter transformer in the inverter are connected with a current detection signal output end by a current sampling circuit, and further feed back current detection signals to the inverter, so as to judge whether to execute the overflow protection. The utility model has advantages of simple structure and low cost, can timely and effectively protect the circuitry against damages when a load has short circuit or open circuit fault, and will not produce false protection when the circuitry is in normal operation, so the utility model is reliable and practical, and is suitable for being popularized and applied in household appliances with very high requirements on costs and reliability.
Description
Technical field
The utility model belongs to the inverter technology field, specifically, relates to a kind of short circuit, breaking protection circuit that is applied in the inverter circuit.
Background technology
Inverter INVERTER is a kind of flyback transformer that direct current is changed into alternating current, the inversion module of direct voltage in inverter of input is transformed into the alternating current of impulse form, and then be transformed into the output of the different alternating voltage of several pulse amplitude through contravariant transformer, adopt high-power to obtain, the high efficiency ac converter output of PWM pulse modulation technology usually.
Inverter circuit since the alternating voltage of output generally up to last kilovolt even several kilovolts; in case the high pressure shorted to earth takes place or causes open circuit conditions because of a variety of causes; as inverter socket disconnection etc.; if can not take safeguard measure timely and effectively, probably cause the injury of human body or phenomenons such as on fire take place.Such as the LCD TV product of present extremely consumer favor, its inner backlight lamp tube drives work by the ac high-voltage that inverter produces.If in user's use, backlight lamp tube opens circuit or during fault such as shorted to earth, if tv product inside lacks effective safeguard measure, very likely injures user's personal safety or causes the damage of liquid crystal TV set.
Traditional solution is varied, and the primary current size of passing through the detection contravariant transformer that has judges whether the execute protection measure; What have then comes the output voltage of contravariant transformer is carried out sampling analysis by divider resistance is set, and short circuit or open circuit fault or the like whether occur with decision circuitry.
These safeguard measures respectively have the pluses and minuses of himself, and the utility model aims to provide a kind of brand-new inverter short circuit, breaking protection circuit.
The utility model content
The purpose of this utility model is to provide a kind of protective circuit that is applied to inverter, load be short-circuited or during open circuit fault with realize to circuitry in time, effectively protection.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of protective circuit that is applied to inverter; on two terminals of described inverter output end, be connected with No. one bleeder circuit respectively; the dividing potential drop node of described bleeder circuit No. one rectification circuit of respectively hanging oneself connects the voltage detection signal output; and then to the inverter fed voltage detection signal, to judge whether to carry out overvoltage protection.
Wherein, described bleeder circuit preferably adopts two electric capacity to be formed by connecting, and one of them is a high-voltage capacitance, and another is a low-voltage capacitance, and described high-voltage capacitance one end connects the lead-out terminal of inverter, and the other end is through described low-voltage capacitance ground connection.
Further, include a two-way diode in described rectification circuit, the negative electrode of one of them diode connects the dividing potential drop node of described bleeder circuit, plus earth; The anode of another one diode connects the dividing potential drop node of described bleeder circuit, and negative electrode connects described voltage detection signal output.
Further again, in described inverter, include inversion module and contravariant transformer, in described contravariant transformer, comprise two secondary coils that the number of turn is identical at least; Wherein, the different name end of the end of the same name of first secondary coil and second subprime coil constitutes two lead-out terminals of described inverter.
In order to realize short-circuit protection, the different name end of described first secondary coil is connected the current detection signal output with the end of the same name of second subprime coil through current sampling circuit, and then to the inverter fed current detection signal, to judge whether to carry out overcurrent protection.
Wherein, in described current sampling circuit, include two sampling resistors, connect one to one with the different name end of first secondary coil of described contravariant transformer and the end of the same name of second subprime coil respectively, and No. one rectification circuit of respectively hanging oneself connects the current detection signal output.In described rectification circuit, then include a diode respectively, the anode of described diode respectively with the different name end of first secondary coil of described contravariant transformer or the corresponding connection of end of the same name of second subprime coil, negative electrode connects described current detection signal output.
Further again, in described inversion module, comprise control chip and inverter circuit, described inverter circuit receives the control signal of control chip output, and then direct voltage is changed into the primary coil that alternating voltage exports described contravariant transformer to; Described control chip receives the detection signal from described voltage detection signal output and current detection signal output, and then determines the state of the control signal of its output.Specifically, promptly when control chip received overvoltage or over-current detection signal, the output control signal stopped the output of inverter circuit.
Further, described contravariant transformer comprises one the tunnel or multichannel.
Compared with prior art; advantage of the present utility model and good effect are: inverter protective circuit of the present utility model is simple in structure; cost is low; when short circuit or open circuit fault appear in load; can in time, effectively protect circuitry to avoid damaging; and when the circuit operate as normal, can not produce the mistake protection, reliable and practical, be adapted at applying in all very high household appliances of cost and reliability requirement.
Description of drawings
Fig. 1 is the circuit theory diagrams of a kind of embodiment of the inverter protective circuit that proposes of the utility model;
Fig. 2 is the circuit theory diagrams of a kind of embodiment of inverter;
Fig. 3 be the utility model embodiment provide normal operation circuit the time a kind of voltage oscillogram by the output of voltage detection signal output and current detection signal output.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is done explanation in further detail.
The design principle of the inverter protective circuit that the utility model proposed is: by connect No. one bleeder circuit respectively on ac voltage output of inverter; low-voltage AC with gained after the dividing potential drop is undertaken feeding back to inverter after the waveform shaping by rectification circuit then; inverter judges just according to the current potential of the voltage detection signal that receives whether load open circuit fault takes place, thereby determines whether to carry out overvoltage protection.In addition, by the electric current that flows through the secondary coil of contravariant transformer in the inverter is sampled, and the sample rate current after the rectification is fed back to inverter, thereby judge the load fault that whether is short-circuited, to determine whether to carry out overcurrent protection.
Embodiment one, and as shown in Figure 1, present embodiment has specifically been enumerated wherein a kind of establishment structure of described short circuit, breaking protection circuit.
Among Fig. 1, T1 is a contravariant transformer, can be one the tunnel, also can be multichannel.It is that example is described in detail that present embodiment only gets one the tunnel.In described contravariant transformer T1, include a primary coil and at least two secondary coils that the number of turn is identical.Wherein, the different name end (i.e. 1 pin) of end of the same name of first secondary coil (i.e. 4 pin) and second subprime coil is as two lead-out terminals of inverter, and the High Level AC Voltage that output obtains after inversion boosting connects load by interface XP1.Be connected with No. one bleeder circuit respectively on the different name end of the end of the same name of described first secondary coil and second subprime coil, in the present embodiment, described bleeder circuit all adopts two electric capacity to be formed by connecting.Wherein, the end of the same name of first secondary coil is through dividing potential drop capacitor C 1, C3 ground connection, and C1 is a high-voltage capacitance, and C3 is a low-voltage capacitance, and its dividing potential drop node connects voltage detection signal output VS1 through a rectification circuit; The different name end of second subprime coil is through dividing potential drop capacitor C 2, C4 ground connection, and wherein, C2 is a high-voltage capacitance, and C4 is a low-voltage capacitance, and its dividing potential drop node connects described voltage detection signal output VS1 with the voltage division signal of taking out through another rectification circuit.Described rectification circuit is a half-wave rectifying circuit, can adopt a two-way diode VD3 or VD4 to realize respectively.As shown in Figure 1, in described bidirectional diode VD3 or VD4, the negative electrode of one of them diode connects the dividing potential drop node of described bleeder circuit, plus earth; The anode of another one diode connects the dividing potential drop node of described bleeder circuit; negative electrode connects described voltage detection signal output VS1; the ac voltage signal that electric capacity is obtained carries out exporting voltage detection signal output VS1 to after the rectification; and then feed back to inverter, to judge whether to carry out overvoltage protection.
In order to realize overcurrent protection; on the end of the same name (i.e. 8 pin) of the different name end (i.e. 5 pin) of first secondary coil of described contravariant transformer T1 and second subprime coil, be connected with the other end ground connection of the described sampling resistor R1 of one road sampling resistor R1, R2, R2 separately; the voltage signal that sampling obtains connects current detection signal output IS1 through rectification circuit; and then feed back to inverter, to judge whether to carry out overcurrent protection.In the present embodiment, described rectification circuit adopts a homophase double diode VD1 to realize, the anode of described homophase double diode VD1 connects one to one with the different name end of first secondary coil of described contravariant transformer T1 and the end of the same name of second subprime coil respectively, negative electrode connects described current detection signal output IS1, to export the current detection signal that sampling obtains.
In described inverter, specifically comprise direct voltage is transformed into the inversion module of alternating voltage and the alternating voltage of inversion module output is carried out boosting inverter, to generate one the tunnel or the contravariant transformer T1 of the different alternating voltage of multichannel amplitude, referring to shown in Figure 2.Wherein, in order to realize that direct voltage is to the conversion between the alternating voltage, in described inversion module, all include a control chip and an inverter circuit usually, described inverter circuit can adopt switch mosfet element commonly used at present to set up and form, receive the PWM pulse-width signal of control chip output, controlling the break-make sequential of its switch element, and then direct voltage is changed into the primary coil (i.e. 6,7 pin) that alternating voltage exports described contravariant transformer T1 to.In order to realize overvoltage, overcurrent protection to described inverter; utilize the detection signal of described control chip reception from voltage detection signal output VS1 and current detection signal output IS1; and then when overvoltage or over current fault took place, the output control signal was to stop the output of inverter circuit.Specifically; control chip compares the voltage detection signal that receives and current detection signal and the inner set point of storage in advance; if detected value surpasses set point; conclude that then short circuit or open circuit fault appear in load; and then enter locking state; promptly block the output of PWM pulse-width signal, quit work, enter guard mode with the control inverter circuit.At this moment, because the secondary of contravariant transformer T1 do not have voltage to export, therefore, played the purpose of design of protection load and circuitry.
Be the concrete course of work of setting forth above-mentioned protective circuit of example to be applied in the liquid crystal TV set below.
First talk about overvoltage protection, i.e. performed safeguard measure during load generation open circuit fault.
When the load operate as normal, be that backlight lamp tube in the liquid crystal display screen is when working properly, the voltage V1 of dividing potential drop node place, the V2 amplitude of the bleeder circuit of being made up of capacitor C 1～C4 are identical, phase place is opposite, become a voltage signal that is equivalent to the similar steamed bun ripple of full-wave rectification through bidirectional diode VD2, VD3, as shown in Figure 3, export the control chip of inverter to through voltage detection signal output VS1.Here; can set the amplitude of voltage V1, V2 lower, thereby make control chip not trigger protection by the appearance value of configuration dividing potential drop capacitor C 1, C2, C3, C4; contravariant transformer T1 drives the luminous operate as normal of backlight lamp tube by interface XP1 output High Level AC Voltage.
When a backlight lamp tube or two backlight lamp tube generation open circuit faults, because the backlight lamp tube self characteristics raises the output end voltage of inverter.At this moment; amplitude by dividing potential drop capacitor C 1, C2, C3, voltage V1, V2 that the C4 dividing potential drop obtains will become very high; after rectification circuit carries out waveform shaping; output amplitude higher voltage signal; and then feed back to the control chip of inverter by voltage detection signal output VS1, to trigger break protecting.
Besides overcurrent protection, i.e. performed safeguard measure when load is short-circuited fault.
When the load operate as normal, be that backlight lamp tube in the liquid crystal display screen is when working properly, because the existence of sampling resistor R1, R2, among Fig. 1, V3, V4 place will get a voltage signal that amplitude is identical, phase place is opposite, become a voltage signal that is equivalent to the similar steamed bun ripple of full-wave rectification through the rectification circuit that constitutes by double diode VD1 in the same way, as shown in Figure 3, export the control chip of inverter to through current detection signal output IS1.Here; can set the amplitude of voltage V3, V4 lower, thereby make control chip not trigger protection by the resistance of configuration sampling resistor R1, R2; contravariant transformer T1 drives the luminous operate as normal of backlight lamp tube by interface XP1 output High Level AC Voltage.
When the backlight lamp tube shorted to earth; the electric current that flows through sampling resistor R1 or R2 will sharply increase; the amplitude of voltage V3, V4 will sharply raise at this moment; after double diode VD1 rectification in the same way; output amplitude higher voltage signal; and then feed back to the control chip of inverter by current detection signal output IS1, to trigger short-circuit protection.
Inverter short circuit of the present utility model, breaking protection circuit are simple in structure, safe and practical, are not only applicable in the higher household appliances of cost and reliability requirement, and can be widely used in the slab bridge drive circuit that all kinds of needs isolate cold and hotly.
Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and variation, remodeling, interpolation or replacement that those skilled in the art are made in essential scope of the present utility model also should belong to protection range of the present utility model.
Claims (10)
1, a kind of protective circuit that is applied to inverter; it is characterized in that: on two terminals of described inverter output end, be connected with No. one bleeder circuit respectively; the dividing potential drop node of described bleeder circuit No. one rectification circuit of respectively hanging oneself connects the voltage detection signal output, so to the inverter fed voltage detection signal to judge whether execute protection.
2, the protective circuit that is applied to inverter according to claim 1 is characterized in that: include a two-way diode in described rectification circuit, the negative electrode of one of them diode connects the dividing potential drop node of described bleeder circuit, plus earth; The anode of another one diode connects the dividing potential drop node of described bleeder circuit, and negative electrode connects described voltage detection signal output.
3, the protective circuit that is applied to inverter according to claim 1 is characterized in that: described bleeder circuit is formed by connecting by two electric capacity.
4, the protective circuit that is applied to inverter according to claim 3; it is characterized in that: in described two electric capacity, one is high-voltage capacitance, and another is a low-voltage capacitance; described high-voltage capacitance one end connects the lead-out terminal of inverter, and the other end is through described low-voltage capacitance ground connection.
5, according to each described protective circuit that is applied to inverter in the claim 1 to 4, it is characterized in that: in described inverter, include inversion module and contravariant transformer, in described contravariant transformer, comprise two secondary coils that the number of turn is identical at least; Wherein, the different name end of the end of the same name of first secondary coil and second subprime coil constitutes two lead-out terminals of described inverter.
6, the protective circuit that is applied to inverter according to claim 5; it is characterized in that: the different name end of described first secondary coil is connected the current detection signal output with the end of the same name of second subprime coil through current sampling circuit, so to the inverter fed current detection signal to judge whether execute protection.
7, the protective circuit that is applied to inverter according to claim 6; it is characterized in that: in described current sampling circuit, include two sampling resistors; connect one to one with the different name end of first secondary coil of described contravariant transformer and the end of the same name of second subprime coil respectively, and No. one rectification circuit of respectively hanging oneself connects the current detection signal output.
8, the protective circuit that is applied to inverter according to claim 7; it is characterized in that: in described rectification circuit, include a diode respectively; the anode of described diode respectively with the different name end of first secondary coil of described contravariant transformer or the corresponding connection of end of the same name of second subprime coil, negative electrode connects described current detection signal output.
9, the protective circuit that is applied to inverter according to claim 6, it is characterized in that: in described inversion module, comprise control chip and inverter circuit, described inverter circuit receives the control signal of control chip output, and then direct voltage is changed into the primary coil that alternating voltage exports described contravariant transformer to; Described control chip receives the detection signal from described voltage detection signal output and current detection signal output, and then determines the state of the control signal of its output.
10, the protective circuit that is applied to inverter according to claim 9 is characterized in that: described contravariant transformer comprises one the tunnel or multichannel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201717774U CN201260073Y (en) | 2008-09-19 | 2008-09-19 | Protection circuit applied to inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201717774U CN201260073Y (en) | 2008-09-19 | 2008-09-19 | Protection circuit applied to inverter |
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| Publication Number | Publication Date |
|---|---|
| CN201260073Y true CN201260073Y (en) | 2009-06-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008201717774U Expired - Fee Related CN201260073Y (en) | 2008-09-19 | 2008-09-19 | Protection circuit applied to inverter |
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| CN (1) | CN201260073Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9553443B2 (en) | 2011-12-29 | 2017-01-24 | General Electric Company | Inverter and power system with fuse protection |
-
2008
- 2008-09-19 CN CNU2008201717774U patent/CN201260073Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9553443B2 (en) | 2011-12-29 | 2017-01-24 | General Electric Company | Inverter and power system with fuse protection |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090617 Termination date: 20120919 |