CN209088529U - Frequency converter output earth short circuit protective device - Google Patents
Frequency converter output earth short circuit protective device Download PDFInfo
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- CN209088529U CN209088529U CN201821360143.3U CN201821360143U CN209088529U CN 209088529 U CN209088529 U CN 209088529U CN 201821360143 U CN201821360143 U CN 201821360143U CN 209088529 U CN209088529 U CN 209088529U
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Abstract
The utility model discloses frequency converter output earth short circuit protective devices, comprising: the first, second, and third resistance branch being mutually in parallel;Signal comparator, the tie point are connected to the first voltage input end to be compared of the signal comparator;Signal criterion potential circuit, one end connects a power supply, and its reference voltage output end connects the second voltage input end to be compared of the signal comparator;Resistance R branch, one end connects a power supply, and its other end is connected with the comparison result output end of the signal comparator and forms a level transition point, and level transition point is connected with interrupt signal pin.The utility model has the beneficial effects that can be responded in time to frequency converter output short circuit current and block frequency converter output, thus avoid short circuit current is excessive, overlong time and caused by device damage;And apparatus structure is simple, without increasing other particular components, thus save cost and occupy frequency converter space it is small.
Description
Technical field
The utility model relates to frequency converters to protect field of circuit technology, protect more particularly to frequency converter output earth short circuit
Device.
Background technique
Frequency converter output earth short circuit is a kind of phenomenon being commonly encountered in application of frequency converter.As motor long term high temperature makes
With motor coil or the continuous aging of motor line of force skin, the class of insulation can gradually reduce and breakdown, and frequency converter is caused to export
To big ground short circuit, frequency converter damage will lead to if not making to protect accordingly to frequency converter output.Domestic frequency converter is to frequency conversion at present
The protection of device itself output earth short circuit is mostly dependent on the band such as output end Hall current sensor or driving optocoupler such as APCL330 VCE
The device of detection is protected, and both the above detection mode has the defect of itself, and the Hall sensor response time is slow, band
The very big electric current of the optocoupler needs of VCE detection just reaches the state of protection, when both the above mode makes frequency converter enter protection
It is very big to export electric current, although can protect, due to the current stress that electric current ambassador winner circuit device is received is big by
Soft water station, after a long time can badly damaged device.
Utility model content
In view of the above technical problems, frequency converter output earth short circuit protective device provided by the utility model, can be right in time
Frequency converter output short circuit current responds and blocks frequency converter output, thus avoid short circuit current is excessive, overlong time and make
At device damage;And apparatus structure is simple, without increasing other particular components, to save cost and occupy frequency converter space
It is small.
Frequency converter output earth short circuit protective device, comprising:
Three-phase current summation signals output device, including the first, second, and third resistance branch being mutually in parallel, described
One, second and one end of 3rd resistor branch be respectively connected to three output ends of frequency converter output three-phase current signal, described the
One, second and the other end of 3rd resistor branch be linked into a tie point simultaneously;
Signal comparator, the tie point are connected to the first voltage input end to be compared of the signal comparator;
Reference voltage generator, one end connects a power supply, and its reference voltage output end connects the signal comparator
The second voltage input end to be compared;
Resistance R branch, one end connect a power supply, and the comparison result output end phase of its other end and the signal comparator
It connects and forms a level transition point, the level transition point is connected with interrupt signal pin.
It is further: it is connected to one second capacitive branch between the tie point and first voltage input end to be compared,
Another termination of second capacitive branch is with reference to ground.
Further: the signal comparator includes first comparator and the second comparator, first, second comparator
The first voltage input end to be compared access the tie point simultaneously;The comparison result output end of first, second comparator
And the other end intersection of the resistance R branch is to form the level transition point.
Further: the reference voltage generator includes positive reference voltage circuit and negative reference voltage circuit, described
Positive reference voltage circuit includes the 4th resistance, the 5th resistance and first capacitor, a foot, the 5th resistance of the 4th resistance
A foot and the first capacitor a foot simultaneously be connected to a little and formed the first reference voltage point, first reference voltage
Point connects the second voltage input end to be compared of the first comparator, and another foot of the 4th resistance connects a power supply, institute
It states another foot of the 5th resistance and another foot of the first capacitor while accessing with reference to ground;The negative reference voltage circuit includes
6th resistance, the 7th resistance and third capacitor, a foot of the 6th resistance, a foot of the 7th resistance and third electricity
The foot held is connected to a little simultaneously and forms the second reference voltage point, and the second reference voltage point connection described second is compared
Another foot of the voltage input end to be compared of the second of device, the 6th resistance connects a power supply, another foot of the 7th resistance
It is accessed simultaneously with another foot of the third capacitor with reference to ground.
It is further: it further include the 4th capacitor and the 5th capacitor, the first voltage input terminal of the first comparator and institute
The foot for stating the 4th capacitor is linked into a power supply together, and another foot of the 4th capacitor connects with reference to ground;The first comparator
Second voltage input terminal a power supply is linked into together with a foot of the 5th capacitor, and another foot of the 5th capacitor connects
With reference to ground.
Compared with prior art, the utility model has the beneficial effects that can be made in time to frequency converter output short circuit current
Respond and block frequency converter output, thus avoid short circuit current is excessive, overlong time and caused by device damage;And present apparatus knot
Structure is simple, without increasing other particular components, thus save cost and occupy frequency converter space it is small.
Detailed description of the invention
Fig. 1 is the structure chart of frequency converter output earth short circuit protective device provided by the embodiment of the utility model.
Fig. 2 is the circuit diagram of frequency converter output earth short circuit protective device provided by the embodiment of the utility model.
Meaning indicated by number in Fig. 1 and Fig. 2 is as follows:
1, three-phase current summation signals output device, 11, first resistor branch, 12, second resistance branch, 13, third electricity
Resistance branch, 14, output end, 15, tie point,
2, signal comparator, the 21, first voltage input end to be compared, the 22, second voltage input end to be compared, 23, second
Capacitive branch, 24, first comparator, the 25, second comparator, 26, level transition point, 27, comparison result output end, 211, first
The voltage input end to be compared of the first of comparator, the first voltage input end to be compared of the 212, second comparator, the 221, first ratio
Compared with the second voltage input end to be compared of device, the second voltage input end to be compared of the 222, second comparator, 241, first compares
The comparison result output end of device, 242, the first voltage input terminal of first comparator, 243, the second voltage of first comparator it is defeated
Enter to hold, the comparison result output end of the 251, second comparator,
3, reference voltage generator, 31, positive reference voltage circuit, 32, negative reference voltage circuit, the 33, first benchmark electricity
Pressure point, the 35, second reference voltage point, the 311, the 4th resistance, the 312, the 5th resistance, 313, first capacitor, the 321, the 6th resistance,
322, the 7th resistance, 323, third capacitor,
4, resistance R branch,
5, the 4th capacitor,
6, the 5th capacitor.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole
Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without making creative work
Every other embodiment obtained, fall within the protection scope of the utility model.
As illustrated in fig. 1 and 2, frequency converter output earth short circuit protective device, comprising:
Three-phase current summation signals output device 1, including the first, second, and third resistance branch (11,12 being mutually in parallel
With 13, i.e., resistance R1 branch, resistance R2 branch and resistance R3 branch as shown in the figure), the first, second, and third resistance branch (11,
12 and one end 13) be respectively connected to frequency converter output three-phase current signal three output ends 14, described first, second, and third
The other end of resistance branch (11,12 and 13) is linked into a tie point 15 (A point as illustrated in the drawing) simultaneously;
Signal comparator 2, tie point 15 are connected to the first voltage input end 21 to be compared of signal comparator 2;Further
Scheme in, one second capacitive branch 23, the second capacitor branch are connected between tie point 15 and the first voltage input end 21 to be compared
23 other end of road ground connection;
Resistance R branch 4, one end connect a power supply, and be positive 5V voltage in the utility model embodiment, and its other end and letter
The comparison result output end 27 of number comparator 2 is connected and forms a level transition point 26, and level transition point 26 is connected with interruption
Signal pins can be the DSP interrupt signal pins of control panel;
In further embodiment, signal comparator 2 includes first comparator 24 and the second comparator 25, the first, second ratio
The first voltage input end (211 and 212) to be compared compared with device (24 and 25) accesses tie point 15 simultaneously;First, second comparator
The other end intersection of the comparison result output end (241 and 251) and resistance R branch 4 of (24 and 25) is to form level conversion
26 (D points as illustrated in the drawing) of point.It further include the 4th capacitor 5 and the 5th capacitor 6, first comparator 24 in further embodiment
First voltage input terminal 242 power supply is linked into together with a foot of the 4th capacitor 5, be positive in the utility model embodiment
15V voltage, another foot of the 4th capacitor 5 connect with reference to ground;The second voltage input terminal 243 and the 5th capacitor 6 of first comparator 24
A foot be linked into a power supply together, be negative 15V voltage in the utility model embodiment, and another foot of the 5th capacitor 6 connects ginseng
Examine ground;And
Reference voltage generator 3, one end connect a power supply, and its 31 connection signal comparator 2 of reference voltage output end
The second voltage input end 22 to be compared;In further embodiment, reference voltage generator 3 includes positive reference voltage circuit 31
With negative reference voltage circuit 32, positive reference voltage circuit 31 includes the 4th resistance 311, the 5th resistance 312 and first capacitor 313,
One foot of one foot of the 4th resistance 311, a foot of the 5th resistance 312 and first capacitor 313 is connected to a little simultaneously and forms the
Reference voltage point 33 (B point as illustrated in the drawing), B point are signal positive reference voltage, the first reference voltage point 33 connection first
The voltage input end 221 to be compared of the second of comparator 24, another foot of the 4th resistance 311 are connected to positive 5V voltage 37, the 5th electricity
Another foot of resistance 312 and another foot of first capacitor 313 access the reference ground of positive 5V voltage simultaneously;Negative reference voltage circuit 32 wraps
It includes including the 6th resistance 321, the 7th resistance 322 and third capacitor 323, the one of a foot of the 6th resistance 321, the 7th resistance 322
One foot of foot and third capacitor 323 is connected to a little simultaneously and forms the second reference voltage point 35 (C point as illustrated in the drawing), C
Point is the negative reference voltage of signal, and the second reference voltage point 35 connects the second voltage input end 222 to be compared of the second comparator 25,
Another foot of 6th resistance 321 is connected to negative 5V voltage 38, another foot of the 7th resistance 322 and another foot of third capacitor 323
The reference ground of negative 5V voltage is accessed simultaneously.
Do further statement to the structure of the utility model embodiment and working principle below: frequency converter exports three-phase current
Signal IU, IV, IW pass through first resistor (R1), second resistance (R2), three branches of 3rd resistor (R3) (11,12 and 13) connection
To a tie point (A point in figure).In conjunction with the principle of the sum of electric current in motor three phase mains, when frequency converter works normally, A point
Voltage value be 0, the reference voltage C of first comparator 24 and the second comparator 25 because of reference voltage B and the C point of B point at this time
In the presence of (in order to improve anti-interference ability in circuit and in conjunction with the current detection signal of frequency converter itself processing and set
The reference voltage B of the first comparator and reference voltage C of the second comparator), two signal comparators (24 and 25) are with high electricity
Flat output, D point voltage are high level;When inverter output terminal is short-circuit relative to the earth, the voltage value of A point is not equal to zero, and A point
Voltage value is raised rapidly with the increase of frequency converter output short circuit current, thus be more than reference voltage B or reference voltage C,
First comparator 24 or the second comparator 25 is set to enter rollover states, the overturning of D point voltage is the DSP that low level is input to control panel
Interrupt signal plays a protective role to block frequency converter output.
Specifically, first comparator 24 is overturn when the voltage of A point is higher than the voltage of B point, D point voltage is turned by high level
Change low level into;When the voltage of A point is lower than the voltage of C point, the second comparator 25 overturning, D point voltage is converted by high level
Low level;D point is high level when frequency converter is normal, the frequency converter block output when D point is low level.To defeated to frequency converter
Short circuit current timely responds to simultaneously act in time out, and it is too late because protecting to solve frequency converter output earth short circuit for block frequency converter output
When and the phenomenon that damage frequency converter;And structure is simple, without increasing other particular components, to save cost and occupy frequency converter
Space is small, to solve the problems, such as that existing scheme cost is excessively high;It is big to solve the problems, such as that existing scheme accounts for frequency converter inner space.
While there has been shown and described that the embodiments of the present invention, for the ordinary skill in the art,
It is understood that these embodiments can be carried out with a variety of variations in the case where not departing from the principles of the present invention and spirit, repaired
Change, replacement and variant, the scope of the utility model is defined by the appended claims and the equivalents thereof.
Claims (3)
1. frequency converter output earth short circuit protective device characterized by comprising
Three-phase current summation signals output device, including the first, second, and third resistance branch being mutually in parallel, described first,
Second and 3rd resistor branch one end be respectively connected to frequency converter output three-phase current signal three output ends, described first,
Second and the other end of 3rd resistor branch be linked into a tie point simultaneously;
Signal comparator, the tie point are connected to the first voltage input end to be compared of the signal comparator;The signal
Comparator includes first comparator and the second comparator, and the first voltage input end to be compared of the first, second comparator is same
When access the tie point;
Reference voltage generator, one end connects a power supply, and its reference voltage output end connects the of the signal comparator
Two voltage input ends to be compared;The reference voltage generator includes positive reference voltage circuit and negative reference voltage circuit, institute
Stating positive reference voltage circuit includes the 4th resistance, the 5th resistance and first capacitor, a foot of the 4th resistance, the 5th electricity
One foot of resistance and a foot of the first capacitor are connected to a little simultaneously and form the first reference voltage point, the first benchmark electricity
Pressure point connects the second voltage input end to be compared of the first comparator, and another foot of the 4th resistance connects a power supply,
Another foot of 5th resistance and another foot of the first capacitor are accessed simultaneously with reference to ground;The negative reference voltage circuit packet
Include the 6th resistance, the 7th resistance and third capacitor, a foot of the 6th resistance, a foot of the 7th resistance and the third
One foot of capacitor is connected to a little simultaneously and forms the second reference voltage point, the second reference voltage point connection second ratio
Compared with the second voltage input end to be compared of device, another foot of the 6th resistance connects a power supply, the 7th resistance it is another
Another foot of foot and the third capacitor is accessed simultaneously with reference to ground;
Resistance R branch, one end connects a power supply, and its other end is connected with the comparison result output end of the first, second comparator
It connects and forms a level transition point, the level transition point is connected with interrupt signal pin.
2. frequency converter output earth short circuit protective device according to claim 1, it is characterised in that: the tie point and institute
It states and is connected to one second capacitive branch between the first voltage input end to be compared, another termination of the second capacitive branch is with reference to ground.
3. frequency converter output earth short circuit protective device according to claim 1, it is characterised in that: further include the 4th capacitor
With the 5th capacitor, the first voltage input terminal of the first comparator is linked into an electricity together with a foot of the 4th capacitor
Source, another foot of the 4th capacitor connect with reference to ground;The second voltage input terminal of the first comparator and the 5th capacitor
A foot be linked into a power supply together, and another foot of the 5th capacitor connects with reference to ground.
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CN201821360143.3U CN209088529U (en) | 2018-08-23 | 2018-08-23 | Frequency converter output earth short circuit protective device |
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CN201821360143.3U CN209088529U (en) | 2018-08-23 | 2018-08-23 | Frequency converter output earth short circuit protective device |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN108879614A (en) * | 2018-08-23 | 2018-11-23 | 深圳市默贝克驱动技术有限公司 | Frequency converter output earth short circuit protects circuit |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN108879614A (en) * | 2018-08-23 | 2018-11-23 | 深圳市默贝克驱动技术有限公司 | Frequency converter output earth short circuit protects circuit |
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