CN102701081B - Frequency converter overload protection system and method thereof - Google Patents
Frequency converter overload protection system and method thereof Download PDFInfo
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- CN102701081B CN102701081B CN201210151882.2A CN201210151882A CN102701081B CN 102701081 B CN102701081 B CN 102701081B CN 201210151882 A CN201210151882 A CN 201210151882A CN 102701081 B CN102701081 B CN 102701081B
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Abstract
The invention provides a frequency converter overload protection system, which comprises an output control unit, a torque calculation unit, an output detection unit and an overload protection unit. The output control unit is used for making the frequency converter reach a set operation frequency and operate at the set frequency for specified time when the frequency converter executes a lifting operation; the output detection unit is used for detecting the output voltage and current of the frequency converter; the torque calculation unit is used for calculating the output torque of the frequency converter according to the output voltage and current; and the overload protection unit is used for determining overload and making the frequency converter execute deceleration and stop operations when the output torque exceeds a set maximum output torque, while disabling the lifting command. The invention also provides a corresponding method. According to the invention, frequency converter overload is determined by detecting the torque in uniform speed operation of the frequency converter, to achieve high overload determination accuracy and low cost.
Description
Technical field
The present invention relates to mechanical and electrical safety field, more particularly, relate to a kind of Frequency converter overload protection system and method.
Background technology
At present; hoisting crane is widely used in the occasions such as camp site, harbour, warehouse, workshop; for lifting building materials, machinery and equipment, goods etc., its work characteristics is that startup is frequent, hoisting capacity is uncertain, often there will be the situation of overload in the course of the work.When overload crane runs, can safety misadventure be caused and damage is caused to the parts of hoisting crane.In order to avoid the safety misadventure of hoisting crane, and extend the service life of hoisting crane, need to carry out overload restriction to hoisting crane.Such as, current lifting industry all requires to install load limiter on lift system.This load limiter part detects by mechanical deformation the load that crane lifting mechanism draws.The overload operation that control mechanism digital quantity signal is used for limiting crane lifting mechanism is exported to according to condition of loading.
But above-mentioned load limiter is expensive, many hoisting crane originating firm commercial cities uneasiness dress or use poor quality, lower-cost load limiter, cause the potential safety hazard of hoisting crane ubiquity overload operation on the market like this.In addition, the phenomenon that current domestic lifting industry ubiquity overload uses, even if producer uses standard, qualified load limiter, user can idea manage to remove load limiter to the restriction of lift system to allow overload crane operation.Based on above two reasons, functionally there is certain defect in what mechanical load limiter ran at restriction overload crane, can not play any restriction even in any case.
Summary of the invention
The technical problem to be solved in the present invention is, for the expensive problem of above-mentioned overload crane killer, provides a kind of Frequency converter overload protection system and method.
The technical scheme that the present invention solves the problems of the technologies described above is, provides a kind of Frequency converter overload protection system, comprises output control unit, torque-calculation unit, output detections unit and overload protection unit; Described output control unit, for when frequency converter performs lifting operation, makes frequency converter run to setpoint frequency and runs the fixed time at this setpoint frequency; Described output detections unit, for detecting output voltage and the electric current of frequency converter; Described torque-calculation unit, for the Driving Torque according to described output voltage and Current calculation frequency converter; Described overload protection unit, for confirming when described Driving Torque exceedes the maximum output torque of setting to overload and making described frequency converter perform ramp to stop operation, generates simultaneously and forbids promoting instruction.
In Frequency converter overload protection system of the present invention, described system also comprises sudden stop unit, for the output brake out code when described overload protection unit confirms overload until frequency converter stops.
In Frequency converter overload protection system of the present invention; described system also comprises promptly transfers unit, performs lowering operation and transferring to remove when torque is less than minimum Driving Torque and forbid promoting instruction at frequency converter for making described frequency converter after described sudden stop unit performs sudden stop.
In Frequency converter overload protection system of the present invention, described torque-calculation unit is by the Driving Torque T:T=a × V × I of following formulae discovery frequency converter, wherein a=9550/N; for constant; N is motor speed is fixed value, and V is the output voltage of frequency converter, and I is the outgoing current of frequency converter.
In Frequency converter overload protection system of the present invention, described setpoint frequency is less than the rated frequency of frequency converter, and the described fixed time is not less than 0.3 second.
The present invention also provides a kind of frequency converter overload protection method, comprises the following steps:
A (), when frequency converter performs lifting operation, makes frequency converter run to setpoint frequency and runs the fixed time at this setpoint frequency;
B () detects the output voltage of frequency converter and electric current, and according to the Driving Torque of described output voltage and Current calculation frequency converter;
C () judges whether described Driving Torque exceedes the maximum output torque of setting, if then confirm that frequency converter overloads and makes described frequency converter perform ramp to stop operation, generate simultaneously and forbid promoting instruction.
In frequency converter overload protection method of the present invention, comprise the following steps after described step (c):
(d1) output brake out code is until frequency converter stops;
(d2) described frequency converter is made to perform lowering operation.
In frequency converter overload protection method of the present invention, comprise the following steps after described step (d2):
(d3) judge transferring torque and whether being less than minimum Driving Torque of frequency converter, if forbid promoting instruction described in then removing, otherwise return step (d2).
In frequency converter overload protection method of the present invention; by the Driving Torque T:T=a × V × I of following formulae discovery frequency converter in described step (b); wherein a=9550/N; for constant; N is motor speed is fixed value; V is the output voltage of frequency converter, and I is the outgoing current of frequency converter.
In frequency converter overload protection method of the present invention, the setpoint frequency in described step (a) is less than the rated frequency of frequency converter, and the described fixed time is not less than 0.3 second.
Frequency converter overload protection system of the present invention and method, torque when traveling at the uniform speed by detecting frequency converter judges whether frequency converter overloads, and the accuracy rate that overload judges is high and cost is extremely low.The present invention is by being integrated into the software simulating of frequency converter, and not easily manufactured manufacturer abandons.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of Frequency converter overload protection system first embodiment of the present invention.
Fig. 2 is the schematic diagram of Frequency converter overload protection system second embodiment of the present invention.
Fig. 3 is the schematic flow sheet of frequency converter overload protection method first embodiment of the present invention.
Detailed description of the invention
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
As shown in Figure 1, be the schematic diagram of Frequency converter overload protection system first embodiment of the present invention.In the present embodiment, system comprises output control unit 11, torque-calculation unit 13, output detections unit 12 and overload protection unit 14.Above-mentioned each unit can by the software simulating being integrated into frequency converter, and utilize original hardware device in frequency converter to carry out corresponding operating; Certain above-mentioned each unit also can adopt the equipment independent of frequency converter to realize.
Output control unit 11, for when frequency converter performs lifting operation (such as weight upwards promotes by hoisting crane), makes frequency converter run to setpoint frequency and runs the fixed time at this setpoint frequency.Now, frequency converter is in the state of traveling at the uniform speed, and its Driving Torque is the torque that this frequency converter pulls load.Above-mentioned setpoint frequency and fixed time all can set according to actual needs, and setpoint frequency is less than the rated frequency of frequency converter usually, and the fixed time is such as more than 0.3 second.
Output detections unit 12 for detecting output voltage V and the outgoing current I of frequency converter after frequency converter travels at the uniform speed the fixed time, and it directly can obtain above-mentioned detected value from the mouth of frequency converter.
Torque-calculation unit 13 calculates the Driving Torque of this frequency converter for the output voltage V that records according to output detections unit 12 and outgoing current I.Theory according to Electrical Motor can be learnt, power P=power × speed, that is: P=F × v (1)
Wherein F is the power acted on object, and v is the speed that object runs.
And torque T=torsion F × radius of action R, that is:
F＝T/R (2)
Linear velocity v=2 π R × rotating speed n per second, then can derive:
v＝πR×N/30 (3)
Wherein N is per minute rotating speed.(3) (2) formula is substituted into formula with formula (1) can obtain:
P＝F*v＝T/R×πRN/30＝π/30×T×N (4)
Wherein P is power, and unit is W; T is torque, and unit is Nm; N is the motor speed of per minute, and unit is r/min.If be kW by the Conversion of measurement unit of P, then above formula can be derived as:
P×1000＝π/30×T×N
30000/3.1415926×P＝T×N
9549.297×P＝T×N
Finally obtain torque calculation formula: T=9550*P/N (5)
Such as, due to motor speed: N=60F/p (p is the p=2 of motor number of pole-pairs, four-stage motor), therefore when output frequency is fixed value, motor speed N is also fixed value.Thus only need know that the horsepower output P of frequency converter can obtain the Driving Torque of frequency converter: T=9550 × V × I/N, i.e. T=a × V × I (wherein a=9550/N is constant).
Confirm overload and make frequency converter perform ramp to stop overload protection unit 14 is for exceeding maximum output torque (this value can according to settings such as the rating horsepowers of frequency converter) of setting during at Driving Torque and operate; generate simultaneously and forbid promoting instruction, namely forbid that frequency converter performs lifting operation again.
Certainly, in actual applications, the power that also can directly travel at the uniform speed by comparing setpoint frequency judges whether to overload with setting maximum power.
In said system, due to frequency converter from execution lifting operation to accelerate to setpoint frequency and the time traveled at the uniform speed very short, therefore the distance of heavy lift is little, once find overload and ramp to stop, thus eliminates potential safety hazard.When above-mentioned unit is integrated into frequency converter, without the need to increasing hardware cost, and not easily abandoned by production firm.
As shown in Figure 2, be the schematic diagram of Frequency converter overload protection system second embodiment of the present invention.This system, except comprising output control unit 21, torque-calculation unit 23, output detections unit 22 and overload protection unit 24, also comprises sudden stop unit 25 and promptly transfers unit 26.
Output brake out code when sudden stop unit 25 is for confirming to overload at overload protection unit is until frequency converter stops.Promptly transfer unit 26 for making frequency converter perform lowering operation after sudden stop unit 25 performs sudden stop and transferring to remove when torque is less than minimum Driving Torque (weight now promoted lands) and forbid promoting instruction at frequency converter, thus frequency converter again can perform lifting operation and carry out overload judgement after loss of weight.Above-mentionedly transfer torque and perform in lowering operation process at frequency converter and detect in real time, and can directly use formula (5) to calculate.Although the result of calculation of the relative formula of actual torque (5) may have error, do not affect weight and land judgement.
As shown in Figure 3, be the diagram of circuit of frequency converter overload protection method first embodiment of the present invention, the method by being integrated into the software of frequency converter or realizing independent of the equipment of frequency converter, can comprise the following steps:
Step S31: when frequency converter performs lifting operation, makes frequency converter run to setpoint frequency and runs the fixed time at this setpoint frequency.Now, frequency converter is in the state of traveling at the uniform speed, and its Driving Torque is the torque that this frequency converter pulls load.Above-mentioned setpoint frequency and fixed time all can set according to actual needs, and setpoint frequency is less than the rated frequency of frequency converter usually, and the fixed time is such as more than 0.3 second.
Step S32: detect the output voltage of frequency converter and electric current, and according to the Driving Torque of output voltage and Current calculation frequency converter.In this step, specifically can calculate the Driving Torque T:T=a × V × I of frequency converter in the following ways, wherein a is constant, and V is the output voltage of frequency converter, and I is the outgoing current of frequency converter.
Step S33: judge whether Driving Torque exceedes the maximum output torque of setting, if then perform step S35, otherwise performs step S34.
Step S34: make frequency converter recover normal and run, such as, accelerate to rated frequency and perform corresponding operating.
Step S35: confirm that frequency converter overloads and makes frequency converter perform ramp to stop operation, generate simultaneously and forbid promoting instruction.
After above-mentioned steps S35, also comprise: output brake out code is until frequency converter stops; Frequency converter is made to perform lowering operation.In execution lowering operation process, by judging transferring torque and whether being less than minimum Driving Torque and judging whether weight lands of frequency converter, forbid promoting instruction if then remove, thus frequency converter again can perform lifting operation and carry out overload judgement after loss of weight.
The above; be only the present invention's preferably detailed description of the invention, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.
Claims (10)
1. a Frequency converter overload protection system, is characterized in that: comprise output control unit, torque-calculation unit, output detections unit and overload protection unit; Described output control unit, for when frequency converter performs lifting operation, makes frequency converter run to setpoint frequency and runs the fixed time at this setpoint frequency; Described output detections unit, for detecting output voltage and the electric current of frequency converter; Described torque-calculation unit, for the Driving Torque according to described output voltage and Current calculation frequency converter; Described overload protection unit, for confirming when described Driving Torque exceedes the maximum output torque of setting to overload and making described frequency converter perform ramp to stop operation, generates simultaneously and forbids promoting instruction.
2. Frequency converter overload protection system according to claim 1, is characterized in that: described system also comprises sudden stop unit, for the output brake out code when described overload protection unit confirms overload until frequency converter stops.
3. Frequency converter overload protection system according to claim 2; it is characterized in that: described system also comprises promptly transfers unit, performing lowering operation for making described frequency converter after described sudden stop unit performs sudden stop and transferring to remove when torque is less than minimum Driving Torque and forbid promoting instruction at frequency converter.
4. Frequency converter overload protection system according to claim 1; it is characterized in that: described torque-calculation unit is by the Driving Torque T:T=a × V × I of following formulae discovery frequency converter; wherein a=9550/N; for constant; N is motor speed is fixed value; V is the output voltage of frequency converter, and I is the outgoing current of frequency converter.
5. the Frequency converter overload protection system according to any one of claim 1-4, is characterized in that: described setpoint frequency is less than the rated frequency of frequency converter, and the described fixed time is not less than 0.3 second.
6. a frequency converter overload protection method, is characterized in that: comprise the following steps:
A (), when frequency converter performs lifting operation, makes frequency converter run to setpoint frequency and runs the fixed time at this setpoint frequency;
B () detects the output voltage of frequency converter and electric current, and according to the Driving Torque of described output voltage and Current calculation frequency converter;
C () judges whether described Driving Torque exceedes the maximum output torque of setting, if then confirm that frequency converter overloads and makes described frequency converter perform ramp to stop operation, generate simultaneously and forbid promoting instruction.
7. frequency converter overload protection method according to claim 6, is characterized in that: comprise the following steps after described step (c):
(d1) output brake out code is until frequency converter stops;
(d2) described frequency converter is made to perform lowering operation.
8. frequency converter overload protection method according to claim 7, is characterized in that: comprise the following steps after described step (d2):
(d3) judge transferring torque and whether being less than minimum Driving Torque of frequency converter, if forbid promoting instruction described in then removing, otherwise return step (d2).
9. frequency converter overload protection method according to claim 6; it is characterized in that: by the Driving Torque T:T=a × V × I of following formulae discovery frequency converter in described step (b); wherein a=9550/N; for constant; N is motor speed is fixed value; V is the output voltage of frequency converter, and I is the outgoing current of frequency converter.
10. the frequency converter overload protection method according to any one of claim 6-9, it is characterized in that: the setpoint frequency in described step (a) is less than the rated frequency of frequency converter, the described fixed time is not less than 0.3 second.
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| CN201210151882.2A CN102701081B (en) | 2012-05-16 | 2012-05-16 | Frequency converter overload protection system and method thereof |
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| CN201210151882.2A CN102701081B (en) | 2012-05-16 | 2012-05-16 | Frequency converter overload protection system and method thereof |
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| CN102701081B true CN102701081B (en) | 2015-06-10 |
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| CN103274297B (en) * | 2013-06-04 | 2015-09-16 | 中联重科股份有限公司 | A kind of tower crane lifting control convenience, method, system and tower machine |
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| CN111362170B (en) * | 2020-03-31 | 2022-06-21 | 三一海洋重工有限公司 | Control method and device for hanger cable reel and crane |
| CN115385247A (en) * | 2022-08-02 | 2022-11-25 | 中联重科建筑起重机械有限责任公司 | Control method, processor and device for tower crane and tower crane |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU981192A1 (en) * | 1981-05-08 | 1982-12-15 | Производственное Объединение "Ждановтяжмаш" | Safety device of crane |
| DE3247369A1 (en) * | 1982-12-22 | 1984-07-05 | Mannesmann AG, 4000 Düsseldorf | Circuit arrangement for load limiting and overload protection of a hoist drive |
| EP1894882A2 (en) * | 2006-08-31 | 2008-03-05 | Liebherr-Werk Nenzing GmbH | Safety and steering method for cranes |
| CN201195665Y (en) * | 2008-02-25 | 2009-02-18 | 江苏省特种设备安全监督检验研究院 | Electrical control equipment for load speed governing crane |
| CN201580908U (en) * | 2009-12-10 | 2010-09-15 | 大连华锐股份有限公司 | Overload protecting system of crane lifting transmission chain |
| CN202080825U (en) * | 2011-05-20 | 2011-12-21 | 王怀军 | Multifunctional load measuring instrument |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04112198A (en) * | 1990-08-29 | 1992-04-14 | Hitachi Ltd | Detection of overload |
| JPH07125987A (en) * | 1993-11-08 | 1995-05-16 | Komatsu Mec Corp | Suspension load/overturning moment detecting device for mobile crane |
| JP4185619B2 (en) * | 1999-03-26 | 2008-11-26 | 住友重機械工業株式会社 | Torque monitoring method for inverter control motor in crane |
-
2012
- 2012-05-16 CN CN201210151882.2A patent/CN102701081B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU981192A1 (en) * | 1981-05-08 | 1982-12-15 | Производственное Объединение "Ждановтяжмаш" | Safety device of crane |
| DE3247369A1 (en) * | 1982-12-22 | 1984-07-05 | Mannesmann AG, 4000 Düsseldorf | Circuit arrangement for load limiting and overload protection of a hoist drive |
| EP1894882A2 (en) * | 2006-08-31 | 2008-03-05 | Liebherr-Werk Nenzing GmbH | Safety and steering method for cranes |
| CN201195665Y (en) * | 2008-02-25 | 2009-02-18 | 江苏省特种设备安全监督检验研究院 | Electrical control equipment for load speed governing crane |
| CN201580908U (en) * | 2009-12-10 | 2010-09-15 | 大连华锐股份有限公司 | Overload protecting system of crane lifting transmission chain |
| CN202080825U (en) * | 2011-05-20 | 2011-12-21 | 王怀军 | Multifunctional load measuring instrument |
Non-Patent Citations (2)
| Title |
|---|
| PLC和变频器在桥式起重机中的应用;倪振峰;《电气传动自动化》;天水电气传动研究所;20101231;第32卷(第6期);第44-47页 * |
| 基于变频器计算转矩的超载限制器研究;王怀军;《起重运输机械》;北京起重运输机械设计研究院;20100831(第8期);第92-94页 * |
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Effective date of registration: 20160229 Address after: Wuzhong District Wuzhong Economic Development Zone, Suzhou City, Jiangsu province 215000 Wang Xiang Shan Industrial Park Road on the north side of friends Patentee after: Suzhou Huichuan Technology Co.,Ltd. Patentee after: Shenzhen Inovance Technology Co., Ltd. Address before: Wuzhong District Wuzhong Economic Development Zone, Suzhou City, Jiangsu province 215000 Wang Xiang Shan Industrial Park Road on the north side of friends Patentee before: Suzhou Huichuan Technology Co.,Ltd. Patentee before: Suzhou Monarch Control Technology Co., Ltd. Patentee before: Shenzhen Inovance Technology Co., Ltd. |