CN204089173U - A kind of frequency changer direct current bus voltage protection circuit - Google Patents
A kind of frequency changer direct current bus voltage protection circuit Download PDFInfo
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- CN204089173U CN204089173U CN201420539251.2U CN201420539251U CN204089173U CN 204089173 U CN204089173 U CN 204089173U CN 201420539251 U CN201420539251 U CN 201420539251U CN 204089173 U CN204089173 U CN 204089173U
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Abstract
A kind of frequency changer direct current bus voltage protection circuit, comprise voltage ratio unit for scaling, voltage threshold setup unit, comparing unit and protection output unit, the input of voltage ratio unit for scaling is connected to the DC bus of frequency converter, for the frequency changer direct current bus collected voltage signal is become a signal conversion voltage according to certain proportional zoom; Voltage threshold setup unit is for obtaining overvoltage threshold voltage and the brownout threshold voltage of setting; The output of input termination voltage ratio unit for scaling of comparing unit and two outputs of voltage threshold setup unit, for comparing the overvoltage threshold voltage of signal conversion voltage and setting and brownout threshold voltage and exporting high level signal or low level signal; The input of protection output unit is connected to the output of comparing unit, for receiving high level signal or the low level signal of comparing unit output, and output protection signal.The utility model available protecting frequency converter, simple and practical, reliability is high.
Description
Technical field
The utility model relates to frequency converter protective circuit field, is specifically related to a kind of frequency changer direct current bus voltage protection circuit.
Background technology
Frequency converter is a kind of more common speed control device in modern electrical equipment, have a very wide range of applications in fields such as boats and ships, iron and steel, papermaking, the functions such as the soft start to AC induction motor, frequency control, raising rotary speed precision and power factor (PF) can be realized.For frequency converter, frequency changer direct current bus overtension can cause damage to the power component of its inside, and may cause frequency converter aircraft bombing, is able to the important leverage of trouble free service so DC bus overvoltage protection is frequency converter.Cause the reason of overvoltage fault to have a lot, when such as inverter load slows down, setting parameter is too short its deceleration time, and brake unit resistance goes wrong etc.
In actual applications, the voltage protection circuit mode of frequency converter has following two kinds:
1, ADC analog quantity detects: detected DC bus-bar voltage, by after resistance step-down sampling, drops on the scope that ADC can detect, thus passes through the fault alarm scope of program setting voltage;
2, comparator detects: the voltage being fixed comparator one end by precision voltage source chip, and comparing with it after detected DC bus-bar voltage sampling, result is exported by comparator.
Along with the development of frequency converter, various protect IC is used for protecting the power model of costliness.But if protect IC is once break down, the over-voltage protecting function on chip can lose efficacy, the consequence produced therefrom will be very serious, likely makes high power switch unit damage.Therefore, design a kind of overvoltage crowbar to become and extremely need.
Summary of the invention
The technical problems to be solved in the utility model is, for the problems referred to above that existing frequency converter work exists because of overvoltage, provides a kind of simple and practical, frequency changer direct current bus voltage protection circuit that reliability is high.
The utility model for solving the problems of the technologies described above adopted technical scheme is:
A kind of frequency changer direct current bus voltage protection circuit, it comprises voltage ratio unit for scaling, voltage threshold setup unit, comparing unit and protection output unit, wherein:
The input of described voltage ratio unit for scaling is connected to the DC bus of frequency converter, for the frequency changer direct current bus collected voltage signal is become a signal conversion voltage according to certain proportional zoom;
Described voltage threshold setup unit is for obtaining overvoltage threshold voltage (magnitude of voltage of corresponding bus voltage upper limit threshold value after ratio conversion) and the brownout threshold voltage (magnitude of voltage of corresponding busbar voltage lower threshold after ratio conversion) of setting;
The output of input termination voltage ratio unit for scaling of described comparing unit and two outputs of voltage threshold setup unit, for comparing the overvoltage threshold voltage of the signal conversion voltage after voltage ratio unit for scaling convergent-divergent and setting and brownout threshold voltage and exporting high level signal or low level signal;
The input of described protection output unit is connected to the output of comparing unit, for receiving high level signal or the low level signal of comparing unit output, and output protection signal.
By such scheme, described voltage ratio unit for scaling comprises resistance R1, resistance R2, resistance R3, resistance R4, resistance R5 and amplifier U1, frequency changer direct current bus positive voltage DC+ is connected with the in-phase input end of amplifier U1 and one end of resistance R3 through resistance R1, the other end ground connection of resistance R3; DC bus negative voltage DC-is connected with the reverse input end of amplifier U1 through resistance R2, one end of the output connecting resistance R5 of amplifier U1, the other end of resistance R5 to be connected with the reverse input end of amplifier U1 and the other end of resistance R5 exports signal conversion voltage DCP through resistance R4;
Described voltage threshold setup unit comprises overvoltage threshold potential circuit and brownout threshold voltage circuit, described overvoltage threshold potential circuit is for obtaining the overvoltage threshold voltage REF1 of setting, and described brownout threshold voltage circuit is for obtaining the brownout threshold voltage REF2 of setting;
Described comparing unit comprises the dual comparator be made up of the first comparator U3 and the second comparator U4, signal conversion voltage DCP connects the reverse input end of the first comparator U3 and the positive input of the second comparator U4, overvoltage threshold voltage REF1 connects the positive input of the first comparator U3, and brownout threshold voltage REF2 connects the reverse input end of the second comparator U4;
Described protection output unit comprises resistance R14, resistance R15, resistance R16 and triode Q1; the output of the first comparator U3 and the second comparator U4 is connected with the base stage of one end of resistance R14 and triode Q1; the other end of resistance R14 is connected with+5V voltage source; the collector electrode of triode Q1 is connected with+5V voltage source through resistance R15; the emitter of triode Q1 is through resistance R16 ground connection, and the emitter of triode Q1 is as the output OV protecting output unit.
By such scheme, described overvoltage threshold potential circuit is by resistance R9, resistance R10, resistance R11, resistance R12, resistance R13, first a reference source Y1 and amplifier U2 composition, the negative electrode of the first a reference source Y1 is connected with+5V voltage source by resistance R9, the plus earth of the first a reference source Y1, the negative electrode of the first a reference source Y1 is extremely connected with the reference of self and accesses+2.5V voltage source, the reference pole of the first a reference source Y1 is connected with the in-phase input end of amplifier U2 through resistance R10, one end ground connection of resistance R11, the other end is connected with the reverse input end of amplifier U2 and resistance R12 respectively, the output of amplifier U2 is connected with one end of resistance R13, the other end of resistance R12 and the other end of resistance R13 and output overvoltage threshold voltage REF1,
Described brownout threshold voltage electricity routing resistance R6, resistance R7, resistance R8 and the second a reference source Y2 form, the negative electrode of the second a reference source Y2 is connected with+5V voltage source by resistance R8, the negative electrode of the second a reference source Y2 is extremely connected with the reference of self, the reference pole of the second a reference source Y2 is connected with one end of resistance R6, the other end of resistance R6 is connected with one end of resistance R7, ground connection after the other end of resistance R7 is connected with the anode of the second a reference source Y2, one end that resistance R6 is connected with resistance R7 exports brownout threshold voltage REF2.
By such scheme, described first a reference source Y1, the second a reference source Y2 all adopt TL431 tri-end adjustable shunt reference source.
By such scheme, described amplifier U1 adopts amplifier TL082.
By such scheme, described first comparator U3 and the second comparator U4 all adopts comparator LM293.
By such scheme, described triode Q1 adopts triode MMB4401LT1.
Operation principle of the present utility model: the frequency changer direct current bus voltage signal collected is become a suitable signal conversion voltage DCP according to certain proportional zoom by voltage ratio unit for scaling; Voltage threshold setup unit setting overvoltage threshold voltage REF1 and brownout threshold voltage REF2; The overvoltage threshold voltage REF1 of the signal conversion voltage DCP after convergent-divergent and setting and brownout threshold voltage REF2 compares by comparing unit; Protection output unit receives high level signal or the low level signal of comparing unit output, and by its output OV output protection signal to controller, controller sends DC bus-bar voltage fault-signal to host computer after judging, when signal conversion voltage DCP exceed setting overvoltage threshold voltage REF1 or lower than setting brownout threshold voltage REF2 time, the dual comparator output low level signal that first comparator U3 and the second comparator U4 forms, now triode Q1 ends, the output OV output low level of the emitter of triode Q1; In like manner, when signal conversion voltage DCP is between the overvoltage threshold voltage REF1 set and brownout threshold voltage REF2, dual comparator exports high level signal, triode Q1 conducting, and the output OV of the emitter of triode Q1 exports high level.Therefore, (the overvoltage threshold voltage of setting and brownout threshold voltage be corresponding frequency changer direct current bus upper voltage limit threshold value and the magnitude of voltage of lower threshold after ratio is changed respectively only need to judge level state that the output OV of the emitter of triode Q1 exports just can to judge whether exceed the operating voltage of setting by frequency changer direct current bus voltage, the signal conversion voltage of ratio corresponding to after convergent-divergent contrasts, the operating voltage whether frequency changer direct current bus voltage exceedes setting can be obtained), by comparison frequency changer direct current bus voltage and the bus voltage upper limit threshold value of the proportional correspondence of this protective circuit, the size of busbar voltage lower threshold, thus make frequency converter at the operated within range meeting busbar voltage bound.The operating voltage of setting is exceeded once frequency changer direct current bus voltage; the output OV output low level of whole protective circuit sends into controller as overvoltage failure alarm signal; and on host computer, inform active user's frequency converter overvoltage fault thus protection frequency converter, frequency converter can be avoided when chip occurs abnormal because of overpressure problems to the heavy damage that it produces like this.
The beneficial effects of the utility model are: by this voltage ratio unit for scaling with comparing unit and protect output unit to compare with overvoltage threshold voltage and brownout threshold voltage signal conversion voltage, output level state, judge whether frequency changer direct current bus voltage exceedes the operating voltage of setting, thus effectively a kind of overvoltage protection means are added to frequency converter, frequency converter is run more safe and reliable; Simple and practical, reliability is high.
Accompanying drawing explanation
Fig. 1 is the logic diagram of the utility model frequency changer direct current bus voltage protection circuit;
Fig. 2 is the circuit theory diagrams of voltage ratio unit for scaling in Fig. 1;
Fig. 3 is the schematic diagram of the overvoltage threshold potential circuit of voltage threshold setup unit in Fig. 1;
Fig. 4 is the schematic diagram of the brownout threshold voltage circuit of voltage threshold setup unit in Fig. 1;
Fig. 5 is the circuit theory diagrams of comparing unit and protection output unit in Fig. 1.
Embodiment
Below in conjunction with drawings and Examples, the utility model is described in detail.
With reference to shown in Fig. 1, frequency changer direct current bus voltage protection circuit described in the utility model, it comprises voltage ratio unit for scaling, voltage threshold setup unit, comparing unit and protection output unit, wherein:
The input of described voltage ratio unit for scaling is connected to the DC bus of frequency converter, for the frequency changer direct current bus collected voltage signal is become a signal conversion voltage according to certain proportional zoom;
Described voltage threshold setup unit is for obtaining overvoltage threshold voltage (magnitude of voltage of corresponding bus voltage upper limit threshold value after ratio conversion) and the brownout threshold voltage (magnitude of voltage of corresponding busbar voltage lower threshold after ratio conversion) of setting;
The output of input termination voltage ratio unit for scaling of described comparing unit and two outputs of voltage threshold setup unit, for comparing the overvoltage threshold voltage of the signal conversion voltage after voltage ratio unit for scaling convergent-divergent and setting and brownout threshold voltage and exporting high level signal or low level signal;
The input of described protection output unit is connected to the output of comparing unit, for receiving high level signal or the low level signal of comparing unit output, and output protection signal.
See Fig. 2, described voltage ratio unit for scaling comprises resistance R1, resistance R2, resistance R3, resistance R4, resistance R5 and amplifier U1, frequency changer direct current bus positive voltage DC+ is connected with the in-phase input end of amplifier U1 and one end of resistance R3 through resistance R1, the other end ground connection of resistance R3; DC bus negative voltage DC-is connected with the reverse input end of amplifier U1 through resistance R2, one end of the output connecting resistance R5 of amplifier U1, the other end of resistance R5 to be connected with the reverse input end of amplifier U1 and the other end of resistance R5 exports signal conversion voltage DCP through resistance R4;
Described voltage threshold setup unit comprises overvoltage threshold potential circuit and brownout threshold voltage circuit, described overvoltage threshold potential circuit is for obtaining the overvoltage threshold voltage REF1 of setting, see Fig. 3, overvoltage threshold potential circuit is by resistance R9, resistance R10, resistance R11, resistance R12, resistance R13, first a reference source Y1 and amplifier U2 composition, + 5V voltage source is connected with the negative electrode of the first a reference source Y1 by resistance R9, the plus earth of the first a reference source Y1, the negative electrode of the first a reference source Y1 is extremely connected with the reference of self and accesses+2.5V voltage source, the reference pole of the first a reference source Y1 is connected with the in-phase input end of amplifier U2 through resistance R10, one end ground connection of resistance R11, the other end is connected with the reverse input end of amplifier U2 and resistance R12 respectively, the output of amplifier U2 is connected with one end of resistance R13, the other end (reverse input end of amplifier U2) of resistance R12 and the other end of resistance R13 and output overvoltage threshold voltage REF1,
Described brownout threshold voltage circuit is for obtaining the brownout threshold voltage REF2 of setting, see Fig. 4, brownout threshold voltage electricity routing resistance R6, resistance R7, resistance R8 and the second a reference source Y2 forms, + 5V voltage source is connected with the negative electrode of the second a reference source Y2 by resistance R8, the negative electrode of the second a reference source Y2 is extremely connected with the reference of self, the reference pole of the second a reference source Y2 is connected with one end of resistance R6, the other end of resistance R6 is connected with one end of resistance R7, ground connection after the other end of resistance R7 is connected with the anode of the second a reference source Y2, one end that resistance R6 is connected with resistance R7 exports brownout threshold voltage REF2.Described first a reference source Y1, the second a reference source Y2 all adopt TL431 tri-end adjustable shunt reference source.
See Fig. 5, described comparing unit comprises the dual comparator be made up of the first comparator U3 and the second comparator U4, signal conversion voltage DCP connects the reverse input end of the first comparator U3 and the positive input of the second comparator U4, overvoltage threshold voltage REF1 connects the positive input of the first comparator U3, and brownout threshold voltage REF2 connects the reverse input end of the second comparator U4;
Described protection output unit comprises resistance R14, resistance R15, resistance R16 and triode Q1, the output of the first comparator U3 and the second comparator U4 is connected with the base stage of one end of resistance R14 and triode Q1, the other end of resistance R14 is connected with+5V voltage source, the collector electrode of triode Q1 is connected with+5V voltage source through resistance R15, the emitter of triode Q1 is through resistance R16 ground connection, the emitter of triode Q1 is connected to as the emitter of the output OV(triode Q1 of protection output unit the output OV be connected with controller), the output OV of protection output unit is connected with controller, output OV output protection signal sends to controller, controller sends DC bus-bar voltage fault-signal to host computer after judging.
In the present embodiment, amplifier U1 adopts amplifier TL082; First comparator U3 and the second comparator U4 all adopts comparator LM293; Triode Q1 adopts triode MMB4401LT1.
Frequency changer direct current bus voltage signal is after the voltage ratio unit for scaling that resistance R1, resistance R2, resistance R3, resistance R4, resistance R5 and amplifier U1 form is scaled to signal conversion voltage DCP, the overvoltage threshold voltage REF1 set with voltage threshold setup unit and brownout threshold voltage REF2 enters after comparing unit that the first comparator U3 and the second comparator U4 forms compares, and sends into the protection output unit be made up of resistance R14, resistance R15, resistance R16 and triode Q1; When signal conversion voltage DCP exceed setting overvoltage threshold voltage REF1 or lower than setting brownout threshold voltage REF2 time, the dual comparator output low level signal that first comparator U3 and the second comparator U4 forms, now triode Q1 ends, the output OV output low level of the emitter of triode Q1; In like manner, when signal conversion voltage DCP is between the overvoltage threshold voltage REF1 set and brownout threshold voltage REF2, dual comparator exports high level signal, triode Q1 conducting, and the output OV of the emitter of triode Q1 exports high level.Therefore, (the overvoltage threshold voltage of setting and brownout threshold voltage be corresponding frequency changer direct current bus upper voltage limit threshold value and the magnitude of voltage of lower threshold after ratio is changed respectively only need to judge level state that the output OV of the emitter of triode Q1 exports just can to judge whether exceed the operating voltage of setting by frequency changer direct current bus voltage, the signal conversion voltage of ratio corresponding to after convergent-divergent contrasts, the operating voltage whether frequency changer direct current bus voltage exceedes setting can be obtained), by comparison frequency changer direct current bus voltage and the bus voltage upper limit threshold value of the proportional correspondence of this protective circuit, the size of busbar voltage lower threshold, thus make frequency converter at the operated within range meeting busbar voltage bound.The operating voltage of setting is exceeded once frequency changer direct current bus voltage; the output OV output low level of whole protective circuit sends into controller as overvoltage failure alarm signal; and on host computer, inform active user's frequency converter overvoltage fault thus protection frequency converter, frequency converter can be avoided when chip occurs abnormal because of overpressure problems to the heavy damage that it produces like this.
The above is only preferred embodiment of the present utility model; not any pro forma restriction is done to the utility model; those skilled in the art utilize the technology contents of above-mentioned announcement to make a little simple modification, and equivalent variations or modification all drop in protection range of the present utility model.
Claims (7)
1. a frequency changer direct current bus voltage protection circuit, is characterized in that: it comprises voltage ratio unit for scaling, voltage threshold setup unit, comparing unit and protection output unit, wherein:
The input of described voltage ratio unit for scaling is connected to the DC bus of frequency converter, for the frequency changer direct current bus collected voltage signal is become a signal conversion voltage according to certain proportional zoom;
Described voltage threshold setup unit is for obtaining overvoltage threshold voltage and the brownout threshold voltage of setting;
The output of input termination voltage ratio unit for scaling of described comparing unit and two outputs of voltage threshold setup unit, for comparing the overvoltage threshold voltage of the signal conversion voltage after voltage ratio unit for scaling convergent-divergent and setting and brownout threshold voltage and exporting high level signal or low level signal;
The input of described protection output unit is connected to the output of comparing unit, for receiving high level signal or the low level signal of comparing unit output, and output protection signal.
2. frequency changer direct current bus voltage protection circuit according to claim 1, it is characterized in that: described voltage ratio unit for scaling comprises resistance R1, resistance R2, resistance R3, resistance R4, resistance R5 and amplifier U1, frequency changer direct current bus positive voltage DC+ is connected with the in-phase input end of amplifier U1 and one end of resistance R3 through resistance R1, the other end ground connection of resistance R3; DC bus negative voltage DC-is connected with the reverse input end of amplifier U1 through resistance R2, one end of the output connecting resistance R5 of amplifier U1, the other end of resistance R5 to be connected with the reverse input end of amplifier U1 and the other end of resistance R5 exports signal conversion voltage DCP through resistance R4;
Described voltage threshold setup unit comprises overvoltage threshold potential circuit and brownout threshold voltage circuit, described overvoltage threshold potential circuit is for obtaining the overvoltage threshold voltage REF1 of setting, and described brownout threshold voltage circuit is for obtaining the brownout threshold voltage REF2 of setting;
Described comparing unit comprises the dual comparator be made up of the first comparator U3 and the second comparator U4, signal conversion voltage DCP connects the reverse input end of the first comparator U3 and the positive input of the second comparator U4, overvoltage threshold voltage REF1 connects the positive input of the first comparator U3, and brownout threshold voltage REF2 connects the reverse input end of the second comparator U4;
Described protection output unit comprises resistance R14, resistance R15, resistance R16 and triode Q1; the output of the first comparator U3 and the second comparator U4 is connected with the base stage of one end of resistance R14 and triode Q1; the other end of resistance R14 is connected with+5V voltage source; the collector electrode of triode Q1 is connected with+5V voltage source through resistance R15; the emitter of triode Q1 is through resistance R16 ground connection, and the emitter of triode Q1 is as the output OV protecting output unit.
3. frequency changer direct current bus voltage protection circuit according to claim 1, it is characterized in that: described overvoltage threshold potential circuit is by resistance R9, resistance R10, resistance R11, resistance R12, resistance R13, first a reference source Y1 and amplifier U2 composition, the negative electrode of the first a reference source Y1 is connected with+5V voltage source by resistance R9, the plus earth of the first a reference source Y1, the negative electrode of the first a reference source Y1 is extremely connected with the reference of self and accesses+2.5V voltage source, the reference pole of the first a reference source Y1 is connected with the in-phase input end of amplifier U2 through resistance R10, one end ground connection of resistance R11, the other end is connected with the reverse input end of amplifier U2 and resistance R12 respectively, the output of amplifier U2 is connected with one end of resistance R13, the other end of resistance R12 and the other end of resistance R13 and output overvoltage threshold voltage REF1,
Described brownout threshold voltage electricity routing resistance R6, resistance R7, resistance R8 and the second a reference source Y2 form, the negative electrode of the second a reference source Y2 is connected with+5V voltage source by resistance R8, the negative electrode of the second a reference source Y2 is extremely connected with the reference of self, the reference pole of the second a reference source Y2 is connected with one end of resistance R6, the other end of resistance R6 is connected with one end of resistance R7, ground connection after the other end of resistance R7 is connected with the anode of the second a reference source Y2, one end that resistance R6 is connected with resistance R7 exports brownout threshold voltage REF2.
4. frequency changer direct current bus voltage protection circuit according to claim 3, is characterized in that: described first a reference source Y1, the second a reference source Y2 all adopt TL431 tri-end adjustable shunt reference source.
5. frequency changer direct current bus voltage protection circuit according to claim 2, is characterized in that: described amplifier U1 adopts amplifier TL082.
6. frequency changer direct current bus voltage protection circuit according to claim 2, is characterized in that: described first comparator U3 and the second comparator U4 all adopts comparator LM293.
7. frequency changer direct current bus voltage protection circuit according to claim 2, is characterized in that: described triode Q1 adopts triode MMB4401LT1.
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| CN201420539251.2U CN204089173U (en) | 2014-09-19 | 2014-09-19 | A kind of frequency changer direct current bus voltage protection circuit |
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| CN201420539251.2U CN204089173U (en) | 2014-09-19 | 2014-09-19 | A kind of frequency changer direct current bus voltage protection circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104218532A (en) * | 2014-09-19 | 2014-12-17 | 中冶南方（武汉）自动化有限公司 | Voltage protection circuit for frequency converter direct current (DC) bus |
| CN108596592A (en) * | 2018-04-19 | 2018-09-28 | 深圳鼎智通讯股份有限公司 | A kind of triggering lock machine method of intelligent terminal |
| CN112505535A (en) * | 2020-11-10 | 2021-03-16 | 广西电网有限责任公司南宁供电局 | Circuit breaker opening and closing characteristic testing method and system |
-
2014
- 2014-09-19 CN CN201420539251.2U patent/CN204089173U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104218532A (en) * | 2014-09-19 | 2014-12-17 | 中冶南方（武汉）自动化有限公司 | Voltage protection circuit for frequency converter direct current (DC) bus |
| CN108596592A (en) * | 2018-04-19 | 2018-09-28 | 深圳鼎智通讯股份有限公司 | A kind of triggering lock machine method of intelligent terminal |
| CN112505535A (en) * | 2020-11-10 | 2021-03-16 | 广西电网有限责任公司南宁供电局 | Circuit breaker opening and closing characteristic testing method and system |
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