CN202111463U - Protection circuit for frequency converter - Google Patents
Protection circuit for frequency converter Download PDFInfo
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- CN202111463U CN202111463U CN2011202175820U CN201120217582U CN202111463U CN 202111463 U CN202111463 U CN 202111463U CN 2011202175820 U CN2011202175820 U CN 2011202175820U CN 201120217582 U CN201120217582 U CN 201120217582U CN 202111463 U CN202111463 U CN 202111463U
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- frequency converter
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- protection circuit
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Abstract
The utility model discloses a protection circuit for a frequency converter. The protection circuit comprises a voltage protection circuit, an over-current protection circuit and a driving protection circuit, wherein the voltage protection circuit is used for acquiring a direct current bus voltage signal coupled by a transformer through a sampling resistor, tracking through an operational amplifier and comparing the signal with a reference signal; the over-current protection circuit is used for acquiring a detection signal through a current detection circuit for detecting three-phase current, processing the detection signal through an operational amplifier and then comparing the detection signal with the reference signal; and the driving protection circuit is used for blocking the driving of the frequency converter through over current, over voltage and under voltage signals so as to forbid the output of the frequency converter and further guarantee that the frequency converter is not damaged due to over current and over voltage. Feedback signals of a voltage detection circuit and the current detection circuit are connected with the driving protection circuit. The circuit has a simple structure and high stability.
Description
Technical field
The utility model relates to a kind of frequency converter, and is especially relevant with the protective circuit of frequency converter.
Background technology
Frequency converter is a kind of device that becomes the power supply of fixed frequency and voltage through electric power, electronic device the power supply of adjustable frequency and voltage.Frequency converter has speed-regulating range width, and adjusting speed accuracy is high, and dynamic response is fast, and low speed torque is big, saves energy, high efficiency, advantage such as easy to use.
Main circuit of converter comprises rectification unit, filtering, energy-storage units and inversion unit.The control section of frequency converter comprises cpu control circuit, secondary power supply circuit, drive circuit and a series of protective circuits such as overcurrent protection, overvoltage protection and overheat protector.The overcurrent of frequency converter and the performance of excess voltage protection are directly connected to the performance and the life-span of frequency converter; As: the fluctuation of line voltage, the connection of power device shutoff or load transient etc. all can cause the change in voltage of frequency changer direct current bus, thereby cause puncturing rectifying tube.That frequency converter output short-circuit, winding damage, load stall, motor quicken is too fast, switching device lost efficacy or disturb misleading of causing can both cause the frequency converter overcurrent; Overcurrent fault is the modal fault of frequency converter always, also is the main reason of damaging frequency converter.Therefore be necessary to take measures to stablize the voltage and current fluctuation of frequency converter.
Summary of the invention
The technical problem that the utility model will solve is to overcome the deficiency that above-mentioned prior art exists, and a kind of protective circuit of frequency converter is provided, and it is simple in structure, good stability, and protective value is good, and cost is low.
For solving the problems of the technologies described above; The utility model provides a kind of protective circuit of frequency converter; Comprise: in order to obtain transformer coupled next DC bus-bar voltage signal through sampling resistor, follow the tracks of, with reference signal voltage protection circuit relatively through operational amplifier; In order to through detecting the current detection circuit of three-phase current, and the current foldback circuit that behind operational amplifier, compares detection signal with reference signal; And, block transducer drive signal in order to the overcurrent, overvoltage and the brownout signal that record through voltage protection circuit and current foldback circuit, forbid frequency converter output, with the Drive Protecting Circuit that guarantees that frequency converter is not damaged by overcurrent and overvoltage; The feedback signal of said voltage protection circuit and said current foldback circuit links to each other with said Drive Protecting Circuit respectively.
The useful technique effect of the utility model is: the protective circuit of this frequency converter is simple in structure, and cost is low, good stability.
Description of drawings
Fig. 1 is the voltage protection circuit of the utility model frequency converter.
Fig. 2 is the current foldback circuit of the utility model frequency converter.
Fig. 3 is the Drive Protecting Circuit of the utility model frequency converter.
Embodiment
The protective circuit of the utility model frequency converter is divided into three parts, i.e. voltage protection circuit, current foldback circuit and Drive Protecting Circuit.Voltage protection circuit is obtained the transformer coupled DC bus-bar voltage signal that comes through sampling resistor, follows the tracks of through operational amplifier, compares to determine its whether overvoltage or under-voltage with reference signal.Current foldback circuit is through detecting the current detection circuit of three-phase current, and detection signal behind operational amplifier, compare its overcurrent whether of judgement with reference signal.The overcurrent that Drive Protecting Circuit records through voltage protection circuit and current foldback circuit, overvoltage and brownout signal are blocked the frequency converter drive circuit; Forbid frequency converter output; To guarantee that frequency converter is not damaged by overcurrent and overvoltage, the feedback signal of voltage protection circuit and current foldback circuit links to each other with Drive Protecting Circuit respectively.
Consult Fig. 1; For the voltage protection circuit of frequency converter, as shown in the figure, the first part of this voltage protection circuit is a voltage follower circuit that is made up of operational amplifier TL072; Obtain the transformer coupled DC bus-bar voltage signal DC VOL that comes through being added in the 3rd pin of operational amplifier TL072 after resistance R 141 and resistance R 143 and the potentiometer VR1 dividing potential drop through sampling resistor; Potentiometer VR1 plays the effect of calibration voltage, and BAV99 is a voltage clamp element, makes VDC end magnitude of voltage maximum over the ground can not surpass 5V; Minimum is 0V, thereby protects its circuit not damaged by high voltage.The VDC signal is transferred to CPU, after software processes, shows its pairing bus voltage value by keyboard LED, and the value of VDC will be as the reference value of frequency converter overvoltage protection and under-voltage protection, and overvoltage protection and under-voltage protection value are by software set.
The latter half of this voltage protection circuit is a comparison circuit; The reference voltage of its 4V obtains and acts on the positive input terminal of LM393 by R147 and R148 dividing potential drop, and the VDC signal acts on the negative input end of LM393, as VCD during less than 4V; OE exports high level; As VCD during greater than 4V, OE output low level, frequency converter overvoltage.
Consult Fig. 2; It is the current foldback circuit of frequency converter, and is as shown in the figure, and U, V port insert by the current detection circuit that detects three-phase current and transmit the signal of coming in; Through be superimposed on the positive-negative input end of operational amplifier TL072-IC2A behind operational amplifier TL072-IC1B, the TL072-IC1A by D3, D4, D5; Output acts on the negative input end of comparator LM393, makes comparisons with the reference voltage of just going into to fail end 3.97 volts (the last voltages got of R27) of LM393, when negative input end voltage during greater than 3.97 volts; The OC output low level, the frequency converter overcurrent.
Port IU place voltage is the instantaneous voltage of difference after R9 and R7 dividing potential drop by+5V voltage and U phase current feedback voltage, that is: IU=2.5+U/2 is because the effect of D1 makes 0V≤IU≤5V; Port IV place voltage is the instantaneous voltage of difference after R8 and R10 dividing potential drop by+5V voltage and V phase current feedback voltage, that is: IV=2.5+V/2 is because the effect of D2 makes 0V≤IV≤5V.IU and IV flow into CPU and carry out routine processes as the value of output current.
Consult Fig. 3, it is the Drive Protecting Circuit of frequency converter, and is as shown in the figure, and OC is the current signal that current foldback circuit records, and OE is the voltage signal that voltage protection circuit records.When OC and any signal of OE change, its circuit output switching activity once, the initial value of OC and OE is a high level; When OC or OE output low level, the 8th pin place output low level of NAND gate chip 74HC00 is because the effect of VCC, R152, Z6, R126; Finally produce the voltage of a 3.5V, thereby beginning T4 is in anti-state partially, thereby is a low level output at signal end DRV-P place in the base stage of T4; And signal end DRV-P links to each other with drive circuit; Thereby the output of drive circuit is blocked, forbid frequency converter output, reach the purpose of protection frequency converter.
The above is merely the preferable possible embodiments of the utility model, and the protection range of unrestricted the utility model, and the equivalent structure that all utilization the utility model specifications and accompanying drawing content have been done changes, and all is included in the protection range of the utility model.
Claims (1)
1. the protective circuit of a frequency converter is characterized in that, comprising: in order to obtain transformer coupled next DC bus-bar voltage signal through sampling resistor, follow the tracks of through operational amplifier, with a reference signal voltage protection circuit relatively; In order to through detecting the current detection circuit of three-phase current, and a current foldback circuit that behind operational amplifier, compares detection signal with reference signal; And, block transducer drive signal in order to the overcurrent, overvoltage and the brownout signal that record through voltage protection circuit and current foldback circuit, forbid frequency converter output, with a Drive Protecting Circuit that guarantees that frequency converter is not damaged by overcurrent and overvoltage; The feedback signal of said voltage protection circuit and said current foldback circuit links to each other with said Drive Protecting Circuit respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202175820U CN202111463U (en) | 2011-06-24 | 2011-06-24 | Protection circuit for frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202175820U CN202111463U (en) | 2011-06-24 | 2011-06-24 | Protection circuit for frequency converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202111463U true CN202111463U (en) | 2012-01-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011202175820U Expired - Fee Related CN202111463U (en) | 2011-06-24 | 2011-06-24 | Protection circuit for frequency converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202111463U (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102545161A (en) * | 2012-02-09 | 2012-07-04 | 西安理工大学 | Overcurrent protection device of variable-frequence governor |
| CN103022976A (en) * | 2012-12-13 | 2013-04-03 | 广州三晶电气有限公司 | Frequency converter output short circuit protection circuit and protection method |
| CN103166183A (en) * | 2013-01-29 | 2013-06-19 | 广东志高空调有限公司 | Protection circuit |
| CN103368366A (en) * | 2012-03-29 | 2013-10-23 | 深圳市安邦信电子有限公司 | Inverter over-current protection circuit |
| 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 |
| CN104852357A (en) * | 2015-05-15 | 2015-08-19 | 上海理工大学 | Over-voltage, under-voltage, and over-current protection circuit of frequency converter |
| CN106786393A (en) * | 2017-03-29 | 2017-05-31 | 深圳市奥地特电气技术有限公司 | A kind of current foldback circuit of AD200 frequency converters |
| CN108023332A (en) * | 2016-10-28 | 2018-05-11 | 沈阳高精数控智能技术股份有限公司 | A kind of under-voltage/over-voltage protection apparatus and method of high response servo-drive |
| CN108155783A (en) * | 2016-12-02 | 2018-06-12 | 长沙市日业电气有限公司 | A kind of circuit for improving overcurrent protection antijamming capability |
-
2011
- 2011-06-24 CN CN2011202175820U patent/CN202111463U/en not_active Expired - Fee Related
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102545161B (en) * | 2012-02-09 | 2014-08-06 | 西安理工大学 | Overcurrent protection device of variable-frequence governor |
| CN102545161A (en) * | 2012-02-09 | 2012-07-04 | 西安理工大学 | Overcurrent protection device of variable-frequence governor |
| CN103368366B (en) * | 2012-03-29 | 2016-10-19 | 深圳市安邦信电子有限公司 | Inverter over-current protection circuit |
| CN103368366A (en) * | 2012-03-29 | 2013-10-23 | 深圳市安邦信电子有限公司 | Inverter over-current protection circuit |
| CN103022976B (en) * | 2012-12-13 | 2015-10-28 | 广州三晶电气有限公司 | A kind of frequency converter output short circuit protection circuit and guard method |
| CN103022976A (en) * | 2012-12-13 | 2013-04-03 | 广州三晶电气有限公司 | Frequency converter output short circuit protection circuit and protection method |
| CN103166183A (en) * | 2013-01-29 | 2013-06-19 | 广东志高空调有限公司 | Protection circuit |
| CN103166183B (en) * | 2013-01-29 | 2015-04-08 | 广东志高空调有限公司 | Protection circuit |
| 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 |
| CN104852357A (en) * | 2015-05-15 | 2015-08-19 | 上海理工大学 | Over-voltage, under-voltage, and over-current protection circuit of frequency converter |
| CN108023332A (en) * | 2016-10-28 | 2018-05-11 | 沈阳高精数控智能技术股份有限公司 | A kind of under-voltage/over-voltage protection apparatus and method of high response servo-drive |
| CN108155783A (en) * | 2016-12-02 | 2018-06-12 | 长沙市日业电气有限公司 | A kind of circuit for improving overcurrent protection antijamming capability |
| CN108155783B (en) * | 2016-12-02 | 2020-09-22 | 长沙市日业电气有限公司 | Circuit for improving overcurrent protection anti-interference capability |
| CN106786393A (en) * | 2017-03-29 | 2017-05-31 | 深圳市奥地特电气技术有限公司 | A kind of current foldback circuit of AD200 frequency converters |
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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: 20120111 Termination date: 20130624 |