CN204886664U - Converter detection device - Google Patents
Converter detection device Download PDFInfo
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- CN204886664U CN204886664U CN201520656348.6U CN201520656348U CN204886664U CN 204886664 U CN204886664 U CN 204886664U CN 201520656348 U CN201520656348 U CN 201520656348U CN 204886664 U CN204886664 U CN 204886664U
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Abstract
The utility model provides a converter detection device, includes: direct current busbar voltage sampling circuit samples to the direct current busbar voltage of converter, direct current busbar voltage maximum value and minimum detection circuitry detect the maximum value and the minimum of this voltage according to direct current busbar voltage's sampled value, load side voltage and current sampling circuit sample to the load side voltage and the electric current of converter, load side voltage virtual value and electric current virtual value computing circuit are according to sampled value this voltage of calculation of load side voltage and electric current and the virtual value of electric current, direct current BUS capacitors discharge time detection circuitry detects direct current BUS capacitors's discharge time according to direct current busbar voltage's sampled value, comparison circuit is according to direct current busbar voltage's a maximum value and a minimum production incoming signal, according to load side voltage and electric current virtual value and direct current BUS capacitors's the 2nd incoming signal of discharge time production to confirm according to an incoming signal and the 2nd incoming signal's comparative result whether direct current BUS capacitors damages.
Description
Technical field
The utility model relates to a kind of frequency-changing device detector, particularly relates to a kind of DC bus capacitor of frequency converter checkout gear.
Background technology
Frequency converter is the electric control appliance controlling alternating current motor by changing machine operation supply frequency mode.Frequency converter is primarily of circuit part compositions such as rectification (AC-DC), filtering, inversions (direct current becomes interchange).What current application was maximum also the widest is AC-DC-AC voltage frequency converter, there is DC energy storage filtering link namely, and the general big capacity electrolyte capacitor device that adopts realizes this function.
As the capacitor continuous firing of DC energy storage filtering link in charging, under discharge condition, and, frequency converter is in the severe operational environment such as high temperature usually, and the growth along with operating time and live load reduces by the service behaviour of DC bus capacitor of frequency converter gradually.Therefore, the device that DC bus capacitor of frequency converter is normally aging in frequency converter is the principal element determining the frequency converter life-span.
At present, check whether DC bus capacitor of frequency converter is aging or damage and periodically carry out mainly through manual type.If fail the aging of Timeliness coverage DC bus capacitor of frequency converter or damage, the damage of whole frequency converter may be caused, for user brings unnecessary loss.
Utility model content
In view of this, the purpose of this utility model is to find that whether DC bus capacitor of frequency converter is aging or damage in time, thus avoids causing damage to whole frequency converter.
To achieve these goals, the utility model provides a kind of frequency-changing device detector, comprising:
DC-bus voltage sampling circuit, it is sampled to the DC bus-bar voltage of described frequency converter;
DC bus-bar voltage maxima and minima testing circuit, it detects the maxima and minima of this voltage according to the sampled value of described DC bus-bar voltage;
Load side voltage and current sampling circuit, it is sampled to the load side voltage of described frequency converter and electric current;
Load side voltage effective value and current effective value counting circuit, it calculates the effective value of this voltage and the effective value of this electric current according to the sampled value of described load side voltage and electric current;
Dc-link capacitance testing circuit discharge time, it detects the discharge time of described DC bus capacitor of frequency converter according to the sampled value of described DC bus-bar voltage;
Comparison circuit, it produces the first input signal according to the maxima and minima of described DC bus-bar voltage, discharge time according to described load side voltage effective value, described load-side current effective value and described dc-link capacitance produces the second input signal, and determines whether described dc-link capacitance damages according to the comparative result of described first input signal and described second input signal.
By the frequency-changing device detector that the utility model provides, DC bus capacitor of frequency converter can be detected in time whether aging or damage, thus avoid causing damage to whole frequency converter, extend the life-span of frequency converter.Further, this detection, without the need to artificial participation, is carried out completely automatically, carrying out alarm, thus making the maintenance of frequency converter more easy, reducing the maintenance cost of frequency converter when finding that DC bus capacitor of frequency converter is aging or damage.
Accompanying drawing explanation
Below with reference to accompanying drawing, by being described in detail to the purpose of this utility model, characteristic sum effect according to specific embodiment of the utility model.These illustrate only for example, not in order to limit protection range of the present utility model.Wherein:
Fig. 1 shows the structural representation according to frequency-changing device detector of the present utility model;
Fig. 2 shows the structural representation of the comparison circuit according to the utility model embodiment;
Fig. 3 shows the structural representation of the DC bus-bar voltage maxima and minima testing circuit according to the utility model embodiment;
Fig. 4 shows the structural representation of dc-link capacitance testing circuit discharge time according to the utility model embodiment.
Embodiment
In the course of work of frequency converter, the energy of inverter load side is provided by DC bus capacitor of frequency converter, and the voltage of DC bus capacitor of frequency converter also becomes a voltage minimum from a voltage max in this discharge process.
Relation between the change in voltage of DC bus capacitor of frequency converter and the energy of inverter load side can be expressed as formula:
Wherein, C
0for the initial capacitance value of DC bus capacitor of frequency converter, U
1for the voltage max of DC bus capacitor of frequency converter, U
2for the voltage minimum of DC bus capacitor of frequency converter, U
3for inverter load side voltage effective value, I
3for inverter load side current effective value, T
0for the discharge time of DC bus capacitor of frequency converter.
If be out of shape by above-mentioned formula (1), following formula can be obtained:
When DC bus capacitor of frequency converter is aging or damage, its capacitance will significantly decline, and the voltage effective value of inverter load side and current effective value can remain unchanged.Then along with the capacitance of DC bus capacitor of frequency converter declines, the equation in above-mentioned formula (2) will be changed to as lower inequality:
According to above-mentioned formula (3), utilize maximum and the voltage effective value of minimum value and inverter load side, the relation between current effective value and the discharge time of DC bus capacitor of frequency converter of frequency changer direct current bus voltage, can detect the aging of DC bus capacitor of frequency converter or damage.
Fig. 1 shows the structural representation according to frequency-changing device detector of the present utility model.As shown in Figure 1, this frequency-changing device detector 10 comprises:
DC-bus voltage sampling circuit 11, it is sampled to the DC bus-bar voltage of described frequency converter;
DC bus-bar voltage maxima and minima testing circuit 12, it detects the maxima and minima of this voltage according to the sampled value of described DC bus-bar voltage;
Load side voltage and current sampling circuit 13, it is sampled to the load side voltage of described frequency converter and electric current;
Load side voltage effective value and current effective value counting circuit 14, it calculates the effective value of this voltage and the effective value of this electric current according to the sampled value of described load side voltage and electric current;
Dc-link capacitance testing circuit discharge time 15, it detects the discharge time of described DC bus capacitor of frequency converter according to the sampled value of described DC bus-bar voltage;
Comparison circuit 16, it produces the first input signal according to the maxima and minima of described DC bus-bar voltage, discharge time according to described load side voltage effective value, described load-side current effective value and described dc-link capacitance produces the second input signal, and determines whether described dc-link capacitance damages according to the comparative result of described first input signal and described second input signal.
By the frequency-changing device detector that the utility model provides, DC bus capacitor of frequency converter can be detected in time whether aging or damage, thus avoid causing damage to whole frequency converter, extend the life-span of frequency converter.Further, this detection, without the need to artificial participation, is carried out completely automatically, carrying out alarm, thus making the maintenance of frequency converter more easy, reducing the maintenance cost of frequency converter when finding that DC bus capacitor of frequency converter is aging or damage.
According in an embodiment of frequency-changing device detector of the present utility model, in order to simplify the circuit realiration of frequency-changing device detector further, above-mentioned formula (3) being out of shape further and can obtaining following formula:
The first input signal that then described comparison circuit 16 produces is the product of the difference of the maxima and minima sum of described DC bus-bar voltage and the maxima and minima of described DC bus-bar voltage.Ask poor by square value computing will be asked to change into, sue for peace and multiplying, the realization more simple economy of described comparison circuit 16 can be made.
The second input signal that described comparison circuit 16 produces is described load side voltage effective value, described load-side current effective value, the discharge time of described dc-link capacitance and the product of a constant.This constant can be determined by the initial capacitance value of described dc-link capacitance based on experience value or by experiment.Such as, can determine based on experience value, when the capacitance of DC bus capacitor of frequency converter drops to 0.8*C
0time, think that DC bus capacitor of frequency converter is aging or damage, then described constant can be set to
Described comparison circuit 16 compares described first input signal and described second input signal, when described first input signal is greater than described second input signal, determines that DC bus capacitor of frequency converter damages.
Fig. 2 shows the structural representation of the comparison circuit according to the utility model embodiment.As shown in Figure 2, this comparison circuit 26 comprises plus/minus method unit 261, multiplication unit 262 and 263 and comparing unit 264.Described plus/minus method unit 261 and described multiplication unit 262 are for calculating described first input signal, described multiplication unit 263 is for calculating described second input signal, and described comparing unit 264 is in comparing described first input signal and described second input signal.When described first input signal is greater than described second input signal, DC bus capacitor of frequency converter aged deterioration can be determined and alarm.
Fig. 3 shows the structural representation of the DC bus-bar voltage maxima and minima testing circuit according to the utility model embodiment.As shown in Figure 3, this DC bus-bar voltage maxima and minima testing circuit 32 comprises maximum value detecting circuit 321 and minimum value testing circuit 322.Wherein, described maximum value detecting circuit 321 comprises comparing unit U1 and operation amplifier unit O1 and O2.As Vin > Vout1, U1 output low level, O1 exports high level; after resistance R1 and R2 amplifies; Vout1 high level output charges to electric capacity C2, until Vin and Vout1 voltage is equal, stops charging to electric capacity C2; C1 and R2 forms low pass filter; filter high-frequency signal, the protection of R3 restriction charging and discharging currents C2, O2 are operated in and penetrate a grade follower state; its output voltage is followed C2 change in voltage and changes, and output and C2 separate.As Vin < Vout1, U1 exports high level, O1 output low level, and diode D1 ends, and Vout1 remains unchanged.Vout1 is current detected voltage max, until new voltage max occurs.K switch 1, in order to discharge voltage on electric capacity C2 to minimum value, makes circuit reset.Consider that U1 mostly is open collector and exports, also can be U1 and pull-up resistor Ru1 is set.Described minimum value testing circuit 322 comprises comparing unit U2 and operation amplifier unit O3 and O4.As Vin < Vout2, U2 output low level, after resistance R4 and R5 amplifies, O3 output low level, electric capacity C4 is discharged by resistance R7, until Vin and Vout2 voltage is equal, stops electric discharge, C3 and R5 forms low pass filter, filter high-frequency signal, R6 reduces concussion, and O4 is operated in and penetrates a grade follower state, its output voltage is followed C4 change in voltage and changes, and output and C4 separate.As Vin > Vout2, U2 exports high level, and O3 exports high level, and diode D2 ends, and Vout2 remains unchanged.Vout2 is current detected voltage minimum, until new voltage minimum occurs.K switch 2, in order to recover magnitude of voltage on C4 to maximum, makes circuit reset.Consider that U2 mostly is open collector and exports, also can be U2 and pull-up resistor Ru2 is set.
Fig. 4 shows the structural representation of dc-link capacitance testing circuit discharge time according to the utility model embodiment.As shown in Figure 4, this dc-link capacitance testing circuit discharge time 45 comprises comparing unit U3 and operation amplifier unit O5.Resistance R8 and electric capacity C5 is in order to realize the phase delay to input signal Vin, and Vin compares with its phase delay signal by comparing unit U3, and during dc-link capacitance electric discharge, U3 exports high level, U3 output low level during dc-link capacitance charging.Utilize resistance R10 and electric capacity C6 to carry out filtering to the output signal of U3 and obtain the DC voltage value that amplitude changes with discharge time.K switch 3, for periodically controlling ground signalling, in order to make the magnitude of voltage on C6 can change along with the change of discharge time, considers that U3 mostly is open collector and exports, for U3 arranges the effect that resistance R9 plays pull-up.Testing result exports by the effect that operation amplifier unit O5 plays follower.Because charging-discharging cycle is fixing (being determined by mains frequency), therefore, discharge time is longer, the duty ratio of the square-wave signal that U3 exports is larger, the DC voltage value that R10 and C6 filtering exports is higher, otherwise, upon discharging more in short-term, the duty ratio of the square-wave signal that U3 exports is less, and the DC voltage value that R10 and C6 filtering exports is lower.Like this, just can detect the discharge time of dc-link capacitance according to the Output rusults Vout3 of O5.
According in an embodiment of frequency-changing device detector of the present utility model, described DC-bus voltage sampling circuit and described load side voltage and current sampling circuit can adopt voltage sensor and current sensor to realize.Described load side voltage effective value and current effective value counting circuit can adopt effective value computing chip, such as LTC1966 or AD736 etc.
In addition, according in an embodiment of frequency-changing device detector of the present utility model, described frequency-changing device detector can also comprise a warning circuit, and it, when described comparison circuit determines that described dc-link capacitance damages, produces an alarm signal.
Those skilled in the art should understand that, although this specification describes according to each embodiment, but not each embodiment only comprises an independently technical scheme, this narrating mode of specification is only for clarity sake, those skilled in the art should by specification integrally, technical scheme in each embodiment also through appropriately combined, can form other execution mode that it will be appreciated by those skilled in the art that.
The foregoing is only exemplifying embodiment, and be not used to limit scope of the present invention.Any those skilled in the art, the equivalent variations done under the prerequisite not departing from design of the present invention and principle, amendment and combination, all should belong to the scope of protection of the invention.
Claims (5)
1. a frequency-changing device detector, is characterized in that, comprising:
DC-bus voltage sampling circuit, it is sampled to the DC bus-bar voltage of described frequency converter;
DC bus-bar voltage maxima and minima testing circuit, it detects the maxima and minima of this voltage according to the sampled value of described DC bus-bar voltage;
Load side voltage and current sampling circuit, it is sampled to the load side voltage of described frequency converter and electric current;
Load side voltage effective value and current effective value counting circuit, it calculates the effective value of this voltage and the effective value of this electric current according to the sampled value of described load side voltage and electric current;
Dc-link capacitance testing circuit discharge time, it detects the discharge time of described DC bus capacitor of frequency converter according to the sampled value of described DC bus-bar voltage;
Comparison circuit, it produces the first input signal according to the maxima and minima of described DC bus-bar voltage, discharge time according to described load side voltage effective value, described load-side current effective value and described dc-link capacitance produces the second input signal, and determines whether described dc-link capacitance damages according to the comparative result of described first input signal and described second input signal.
2. frequency-changing device detector as claimed in claim 1, is characterized in that,
Described first input signal is the product of the difference of the maxima and minima sum of described DC bus-bar voltage and the maxima and minima of described DC bus-bar voltage;
Described second input signal is described load side voltage effective value, described load-side current effective value, the discharge time of described dc-link capacitance and the product of a constant; Further,
When described first input signal is greater than described second input signal, determine that described dc-link capacitance damages.
3. frequency-changing device detector as claimed in claim 2, is characterized in that,
Described constant is determined according to the initial capacitance value of described dc-link capacitance.
4. frequency-changing device detector as claimed in claim 3, is characterized in that,
Described constant is
wherein, C
0for the initial capacitance of described dc-link capacitance.
5. the frequency-changing device detector as described in as arbitrary in above-mentioned Claims 1-4, is characterized in that, also comprise:
One warning circuit, it, when described comparison circuit determines that described dc-link capacitance damages, produces an alarm signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520656348.6U CN204886664U (en) | 2015-08-27 | 2015-08-27 | Converter detection device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520656348.6U CN204886664U (en) | 2015-08-27 | 2015-08-27 | Converter detection device |
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| CN204886664U true CN204886664U (en) | 2015-12-16 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109596923A (en) * | 2018-12-24 | 2019-04-09 | 日立电梯（中国）有限公司 | Frequency converter bus capacitor on-line measuring device, method and frequency converter |
| CN112798869A (en) * | 2019-11-13 | 2021-05-14 | 南京国电南自新能源科技有限公司 | Capacitance detection method and system for unit series type converter |
| CN113612424A (en) * | 2021-08-05 | 2021-11-05 | 四川虹美智能科技有限公司 | Bus capacitor capacity monitoring method of permanent magnet synchronous motor driving system |
| CN116577590A (en) * | 2023-06-13 | 2023-08-11 | 深圳正泰电源系统有限公司 | Inverter self-checking method |
| CN116683822A (en) * | 2023-08-04 | 2023-09-01 | 长治市本立科技有限公司 | Energy-saving control method and system for dynamic load tracking frequency converter |
-
2015
- 2015-08-27 CN CN201520656348.6U patent/CN204886664U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109596923A (en) * | 2018-12-24 | 2019-04-09 | 日立电梯（中国）有限公司 | Frequency converter bus capacitor on-line measuring device, method and frequency converter |
| CN112798869A (en) * | 2019-11-13 | 2021-05-14 | 南京国电南自新能源科技有限公司 | Capacitance detection method and system for unit series type converter |
| CN113612424A (en) * | 2021-08-05 | 2021-11-05 | 四川虹美智能科技有限公司 | Bus capacitor capacity monitoring method of permanent magnet synchronous motor driving system |
| CN113612424B (en) * | 2021-08-05 | 2023-06-23 | 四川虹美智能科技有限公司 | Bus capacitor capacity monitoring method of permanent magnet synchronous motor driving system |
| CN116577590A (en) * | 2023-06-13 | 2023-08-11 | 深圳正泰电源系统有限公司 | Inverter self-checking method |
| CN116683822A (en) * | 2023-08-04 | 2023-09-01 | 长治市本立科技有限公司 | Energy-saving control method and system for dynamic load tracking frequency converter |
| CN116683822B (en) * | 2023-08-04 | 2023-10-17 | 长治市本立科技有限公司 | Energy-saving control method and system for dynamic load tracking frequency converter |
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