CN105655982B - Output current of frequency converter detection circuit and its detection method - Google Patents
Output current of frequency converter detection circuit and its detection method Download PDFInfo
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- CN105655982B CN105655982B CN201610186861.2A CN201610186861A CN105655982B CN 105655982 B CN105655982 B CN 105655982B CN 201610186861 A CN201610186861 A CN 201610186861A CN 105655982 B CN105655982 B CN 105655982B
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- phase current
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- hall sensor
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
Abstract
The invention discloses a kind of output current of frequency converter detection circuit and its detection methods, the circuit includes the first Hall sensor, the second Hall sensor, rp-op amp, adder calculator, reverse phase arithmetic unit, respectively there is two-phase power supply line to pass through in first Hall sensor, the second Hall sensor, and an only phase power cord is mutually identical as one in the two-phase power supply line in the second Hall sensor in the two-phase power supply line of the first Hall sensor；First Hall sensor exports first detection signal, second Hall sensor output the second detection signal, first detection signal and the second detection signal obtain the first phase current signal and the second phase current signal after inverted operational amplifier operation respectively, first phase current signal and the second phase current signal are input to adder calculator again through a reverse phase arithmetic unit, obtain third phase current signal.The present invention can also be achieved the short-circuit protection of alternate and output relatively, have the advantages that simple in structure, at low cost.
Description
Technical field
The present invention relates to current detecting research field, more particularly to a kind of output current of frequency converter detection circuit and its detection
Method.
Background technology
Currently, the detection of output current of frequency converter is generally adopted in the following method：Using three Hall sensors or divide
Stream device (A, B, C) is respectively detected three-phase output current U, V, W of frequency converter, and structure is referring to Fig. 1.In each power cord
On a Hall sensor or current divider is respectively set.In this way, the size that can detect three-phase output current, into
The short-circuit protection of row U, V, W three-phase short-circuit protection between phase and phase and three-phase ground-to-ground (PE).
In practical applications, when being detected to the size of three-phase output current, zero original is added up to according to three-phase current
Reason, it is only necessary to detect that any of which biphase current, another phase can be obtained by calculating.In addition, U, V, W three-phase phase and phase
Between short-circuit protection specifically refer to detection U and V or U and W or V and W it is whether short-circuit, this phase fault equally only needs to examine
Measure arbitrary two-phase.But, the short-circuit protection that U, V, W three-phase distinguish (PE) over the ground is carried out, needs to have suddenly above three-phase
You could realize current detecting, referring to Fig. 2, if Hall sensor (A, B) is only arranged on the power cord of U, V two-phase carries out electricity
Stream detection easily leads to frequency converter damage then will be unable to protect when W relative ground circuits.Based on this consideration, although three-phase exports
Size and the phase fault protection of electric current can be realized with 2 sensors, but three-phase output cannot be accomplished to PE short circuits
Protection.Therefore general existing frequency converter still uses three sensors, i.e. U, V, respectively with a sensor above W three-phases.
Invention content
The shortcomings that it is a primary object of the present invention to overcome the prior art and deficiency provide a kind of output current of frequency converter inspection
Slowdown monitoring circuit can realize the detection of three-phase current only with two Hall sensors in the detection circuit, but can realize it is alternate with
And short-circuit protection relatively, save cost.
Another object of the present invention is to provide a kind of detection method based on above-mentioned output current of frequency converter detection circuit,
Numerical value that this method is acquired according to two Hall sensors, by calculating can obtain three-phase current and it is each relatively
Electric current, to realize protection.
The purpose of the present invention is realized by the following technical solution：Output current of frequency converter detection circuit, including first suddenly
That sensor, the second Hall sensor, rp-op amp, adder calculator, reverse phase arithmetic unit, first hall sensing
Respectively there is two-phase power supply line to pass through in device, the second Hall sensor, and in the two-phase power supply line of the first Hall sensor
An only phase power cord is mutually identical as one in the two-phase power supply line in the second Hall sensor；First Hall sensor is defeated
Go out first detection signal, the second Hall sensor output the second detection signal, first detection signal and the second detection signal difference
Obtain the first phase current signal and the second phase current signal after inverted operational amplifier operation, first phase current signal and
Second phase current signal is input to adder calculator again through a reverse phase arithmetic unit, obtains third phase current signal.The present invention passes through
Said program realizes the detection of three-phase current only with two Hall sensors, and realize alternate and relatively short
Road is protected, and is had the advantages that at low cost.
Preferably, between first Hall sensor and rp-op amp, the second Hall sensor and reverse phase fortune
It calculates and is equipped with first voltage lifting circuit between amplifier, first voltage lifting circuit is used for first detection signal and the
Sine wave lifting in two detection signals originally on the basis of 0V is the sine wave on the basis of 2.5V.
Preferably, the output current of frequency converter detection circuit further includes comparison circuit, first phase current signal,
Two-phase current signal, third phase current signal are separately input to comparison circuit, and comparison circuit is used for the first phase current signal, the
Two-phase current signal, third phase current signal are compared with preset overcurrent protection threshold value respectively, once overcurrent occurs, are then sent
Control signal arrive frequency converter CPU, and then trigger frequency converter short-circuit protection circuit progress short-circuit protection.
Further, it is equipped with second voltage before the comparison circuit and is lifted circuit, the second voltage is lifted circuit
For the lift of the sine wave on the basis of 0V to be carried out in the first phase current signal, the second phase current signal, third phase current signal Central Plains
The sine wave being upgraded on the basis of 2.5V.
A kind of detection method based on above-mentioned output current of frequency converter detection circuit is equal to first according to first detection signal
The negative value of phase current signal, the second detection signal are equal to the negative value of the second phase current signal, the first phase current signal, two phase electricity
Stream signal, third phase current signal are added and are zero, obtain third phase current signal；A default overcurrent protection threshold value, by first
Phase current signal, the second phase current signal, third phase current signal three value compared respectively with the overcurrent protection threshold value, one
Denier is more than the overcurrent protection threshold value, then sends the short-circuit protection that control signal realizes frequency converter.
Compared with prior art, the present invention having the following advantages that and advantageous effect：
The detection of existing inverter current and overcurrent protection (especially tri- relative ground circuit of U, V, W is protected) with three suddenly
You realize sensor, and the present invention only needs to can be realized using two Hall sensors, is each passed through in each Hall sensor
Two output lines, and the output of a wherein phase will be also cross two Hall sensors, according to the measured value of Hall sensor
U, V, W three-phase output current are obtained by corresponding relationship and carries out three relative ground circuit protections, are saved cost, are made system
More simplify.
Description of the drawings
Fig. 1 is the one of which connection relationship diagram of Hall sensor and power cord in existing inverter current detection.
Fig. 2 is that the wherein another connection relation of Hall sensor and power cord is illustrated in existing inverter current detection
Figure.
Fig. 3 is the connection relationship diagram of Hall sensor and power cord in 1 current detecting of the embodiment of the present invention.
Fig. 4 is the circuit diagram of 1 current detection circuit of the embodiment of the present invention.
Fig. 5 is to obtain the circuit diagram of third phase current using adder calculator in the embodiment of the present invention 1.
Fig. 6 is the connection relationship diagram of Hall sensor and power cord in 2 current detecting of the embodiment of the present invention.
Fig. 7 is the connection relationship diagram of Hall sensor and power cord in 3 current detecting of the embodiment of the present invention.
Specific implementation mode
Present invention will now be described in further detail with reference to the embodiments and the accompanying drawings, but embodiments of the present invention are unlimited
In this.
Embodiment 1
As shown in figure 3, the present embodiment output current of frequency converter detection circuit includes the first Hall sensor A, the second Hall
Sensor B, the first Hall sensor A pass through U phases and V phases in U, V, W three-phase power line, the second Hall sensor B pass through U,
V, the W phases and V phases in W three-phase power lines may be implemented two functions of current detecting and short-circuit protection by the circuit, tie below
Circuit diagram is closed it is specifically described.
One, current detecting
Referring to Fig. 4 and Fig. 5, by taking the first Hall sensor A as an example, the first Hall sensor A exports first detection signal, should
Detection signal first passes through the first voltage lifting circuit of the compositions such as R569, R570, and first voltage is lifted circuit and the first detection is believed
Number originally point was lifted to the sine wave lifting for the voltage waveform benchmark put centered on 2.5V as using 2.5V as base centered on 0V
Accurate sine wave.Then rp-op amp IC505 is sent signal to, first is obtained after inverted operational amplifier operation
Phase current signal, the signal are W phase current signals.
Similarly, the second Hall sensor B first passes through the first voltage lifting circuit of the compositions such as R603, R604, then passes through
The second phase current signal is obtained after crossing the operation of rp-op amp MC34074, which is U phase current signals.
After obtaining W phase current signals and U phase current signals, using circuit shown in fig. 5, two paths of signals is input to and is added
After method arithmetic unit third phase current signal, i.e. V phase current signals are obtained through a reverse phase arithmetic unit again.
So far, the present embodiment realizes the detection of three-phase current only with two Hall sensors, can will obtain
Current signal is sent to external controller for operations such as storage, the detections of current signal.
Two, short-circuit protection
After obtaining three-phase current by foregoing circuit, U, V, W three-phase between phase and phase short can also be further carried out
Road is protected and the short-circuit protection of three relatively (PE).Short-circuit protection is realized by comparing circuit.
Referring to Fig. 4, by taking the first Hall sensor A as an example, after detection obtains W phase currents, second voltage lifting electricity is first passed through
Road (including R535, R544, R536 etc.), second voltage are lifted circuit the sine on the basis of 0V originally in W phase current signals
Wave lifting is sine wave on the basis of 2.5V, is then input to comparison circuit (see the IC501 in figure), and comparison circuit is by W phases
Current signal is compared with preset overcurrent protection threshold value, if it exceeds overcurrent protection threshold value, then send control signals to frequency conversion
The CPU of device, and then trigger frequency converter short-circuit protection circuit and carry out short-circuit protection.
Similarly, the second Hall sensor B is detected after obtaining U phase currents, first pass through second voltage lifting circuit (including
R609, R610, R611 etc.), second voltage be lifted circuit in U phase current signals by originally centered on 0V point be lifted to
The voltage waveform put centered on 2.5V is then input to comparison circuit (see the IC502 in figure), and comparison circuit believes U phase currents
It number is compared with preset overcurrent protection threshold value, if it exceeds overcurrent protection threshold value, then send control signals to frequency converter
CPU, and then trigger frequency converter short-circuit protection circuit and carry out short-circuit protection.
Through this embodiment, phase fault and relatively (PE) short circuit can be detected, it is achieved that only with two
Hall sensor carries out short-circuit protection, has the advantages that simple in structure, at low cost.
Embodiment 2
The present embodiment in addition to following characteristics other structures with embodiment 1：
In embodiment 1, the first Hall sensor A passes through U phases and V phases in U, V, W three-phase power line, the second hall sensing
Device B passes through W phases and V phases in U, V, W three-phase power line, and in the present embodiment, U phases are passed through referring to Fig. 6, the first Hall sensor A
With W phases, output first detection signal is-V, and the second Hall sensor B passes through W phases and V phases, output the second detection signal-U to lead to
It crosses using circuit shown in Fig. 4,5, U, V, W three-phase current signal can be obtained, and then can realize short circuit according to three-phase current signal
Protection.
Embodiment 3
The present embodiment in addition to following characteristics other structures with embodiment 1：
In the present embodiment, it is-V to pass through U phases and W phases, output first detection signal referring to Fig. 7, the first Hall sensor A,
Second Hall sensor B passes through U phases and V phases, the second detection of output signal-W that can be obtained by using circuit shown in Fig. 4,5
U, V, W three-phase current signal, and then can realize short-circuit protection according to three-phase current signal.
The above embodiment is a preferred embodiment of the present invention, but embodiments of the present invention are not by above-described embodiment
Limitation, it is other it is any without departing from the spirit and principles of the present invention made by changes, modifications, substitutions, combinations, simplifications,
Equivalent substitute mode is should be, is included within the scope of the present invention.
Claims (3)
1. output current of frequency converter detection method, which is characterized in that be based on following detection circuit, detection circuit includes the first Hall
Sensor, the second Hall sensor, rp-op amp, adder calculator, reverse phase arithmetic unit, first hall sensing
Respectively there is two-phase power supply line to pass through in device, the second Hall sensor, and in the two-phase power supply line of the first Hall sensor
An only phase power cord is mutually identical as one in the two-phase power supply line in the second Hall sensor；First Hall sensor is defeated
Go out first detection signal, the second Hall sensor output the second detection signal, first detection signal and the second detection signal difference
Obtain the first phase current signal and the second phase current signal after inverted operational amplifier operation, first phase current signal and
Second phase current signal is input to adder calculator again through a reverse phase arithmetic unit, obtains third phase current signal；
The output current of frequency converter detection circuit further includes comparison circuit, first phase current signal, the second phase current letter
Number, third phase current signal be separately input to comparison circuit, comparison circuit is used to believe in the first phase current signal, the second phase current
Number, third phase current signal compared respectively with preset overcurrent protection threshold value, once occur overcurrent, then send control signals to
The CPU of frequency converter, and then trigger frequency converter short-circuit protection circuit and carry out short-circuit protection；
Detection method step is：It is equal to the negative value of the first phase current signal according to first detection signal, the second detection signal is equal to
The negative value of second phase current signal, the first phase current signal, the second phase current signal, third phase current signal are added and are zero,
Obtain third phase current signal；A default overcurrent protection threshold value, by the first phase current signal, the second phase current signal, third phase
The value of current signal three is compared with the overcurrent protection threshold value respectively, once being more than the overcurrent protection threshold value, then sends control
Signal realizes the short-circuit protection of frequency converter.
2. output current of frequency converter detection method according to claim 1, which is characterized in that first Hall sensor
First voltage lifting electricity is equipped between rp-op amp, between the second Hall sensor and rp-op amp
Road, first voltage lifting circuit are used for the sine on the basis of 0V originally in first detection signal and the second detection signal
Wave lifting is the sine wave on the basis of 2.5V.
3. output current of frequency converter detection method according to claim 1, which is characterized in that set before the comparison circuit
There is second voltage to be lifted circuit, second voltage lifting circuit is used for the first phase current signal, the second phase current signal, the
Sine wave lifting in three-phase current signal originally on the basis of 0V is the sine wave on the basis of 2.5V.
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| CN201610186861.2A CN105655982B (en) | 2016-03-28 | 2016-03-28 | Output current of frequency converter detection circuit and its detection method |
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| CN105655982A CN105655982A (en) | 2016-06-08 |
| CN105655982B true CN105655982B (en) | 2018-10-30 |
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| CN111812385A (en) * | 2020-07-22 | 2020-10-23 | 南京工业职业技术学院 | Three-phase bus current detection method |
| CN112415418B (en) * | 2020-10-23 | 2022-05-24 | 湖南中科电气股份有限公司 | Electromagnetic stirring variable frequency power supply fault detection circuit |
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| CN101329090A (en) * | 2007-06-20 | 2008-12-24 | 乐金电子(天津)电器有限公司 | Variable frequency air conditioner outdoor machine |
| CN103499736A (en) * | 2013-10-22 | 2014-01-08 | 重庆长安汽车股份有限公司 | Over-current detection circuit and over-current protection circuit |
| CN103605396A (en) * | 2013-11-22 | 2014-02-26 | 苏州汇川技术有限公司 | Converter output current processing circuit and converter output current processing method |
| CN105140899A (en) * | 2015-08-04 | 2015-12-09 | 西北工业大学 | Current-limiting protection device of high-power permanent-magnet brushless direct-current motor |
| CN205646778U (en) * | 2016-03-28 | 2016-10-12 | 广州七喜智能设备有限公司 | Converter output current detection circuitry |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6033529B2 (en) * | 2011-05-30 | 2016-11-30 | 株式会社東海理化電機製作所 | Detection device and current sensor |
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- 2016-03-28 CN CN201610186861.2A patent/CN105655982B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101329090A (en) * | 2007-06-20 | 2008-12-24 | 乐金电子(天津)电器有限公司 | Variable frequency air conditioner outdoor machine |
| CN103499736A (en) * | 2013-10-22 | 2014-01-08 | 重庆长安汽车股份有限公司 | Over-current detection circuit and over-current protection circuit |
| CN103605396A (en) * | 2013-11-22 | 2014-02-26 | 苏州汇川技术有限公司 | Converter output current processing circuit and converter output current processing method |
| CN105140899A (en) * | 2015-08-04 | 2015-12-09 | 西北工业大学 | Current-limiting protection device of high-power permanent-magnet brushless direct-current motor |
| CN205646778U (en) * | 2016-03-28 | 2016-10-12 | 广州七喜智能设备有限公司 | Converter output current detection circuitry |
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