CN106093677A - A kind of three level active wave filter IGBT open fault localization methods - Google Patents

Abstract

A kind of three level active wave filter IGBT open fault localization methods, belong to frequency converter IGBT method for diagnosing faults.Method for diagnosing faults, by two kinds of concrete grammar observation active filter three-phase output point X current potentials to dc bus midpoint M, and determines the concrete position that open fault IGBT occurs by similarity-rough set；A kind of method is to obtain the potential difference to bus midpoint M for the three-phase output point X in real time by Circuit theory loop equation, represents actual real potential difference；Another kind of method be first assume that 4 IGBT of X phase open a way respectively after, calculated by current loop analysis and draw the potential difference to bus midpoint M for the three-phase output point X after 4 IGBT open circuits of X phase, represent the potential difference deducing.Supposition potential difference has and only one of which waveform is close with the potential difference that first method is tried to achieve, thus judge fault.Advantage: 1) independent of load type.2) still can be with Precise Diagnosis in the case of load changing；3) accuracy is high, and 4) do not need extra hardware cost.

Description

A kind of three level active wave filter IGBT open fault localization methods

Technical field

The present invention relates to a kind of frequency converter IGBT method for diagnosing faults, particularly a kind of three level active wave filter IGBT open Road Fault Locating Method.

Background technology

Frequency converter is widely used in electric machine speed regulation field.Frequency converter must use the power switch device of high switching frequency Part.Device for power switching usually has the situation of damage to occur, and once power device fault occurs even to lead affecting system work Cause to shut down.According to statistics, power device fault occupies more than the 70% of frequency converter failure, therefore enters power device fast and effectively Row fault location, and it is most important for frequency converter with fault-tolerant measure to make protection.

Research has discovered that a lot of transducer power device fault diagnostic method, such as PARK vector method, neutral net Method etc..These methods are only suitable for and frequency conversion speed-adjusting system, are not suitable for active filter, and basic reason is because that motor is adjusted The target of speed is the sineization realizing electric current.For frequency converter, during malfunction, electric current is no longer sinusoidal, this be easy to into Row differentiates.But during for active filter, the accuracy of these determination methods greatly reduces.Because active filter electric current The target of output is not sinusoidal in most cases, the even normal condition current ratio electric machine speed regulation frequency converter of active filter Malfunction electric current more irregular.And active filter is sometimes for compensating zero-sequence component, therefore power device fault is sentenced Disconnected difficulty is very big.

Traditional IGBT method for diagnosing faults, the general normally work output electric current that is only suitable for is sinusoidal situation, Er Qiechuan The accuracy of system method for diagnosing faults is limited by loading, inapplicable under a lot of loading conditions.Traditional detection method is general It is not suitable for the situation of three-phase current unbalance.Other conventional method is easy to feelings wrong diagnosis occur when load changing Condition.

Content of the invention

The invention aims to provide a kind of three level active wave filter IGBT open fault localization methods, solve existing The very big problem of the power device breakdown judge difficulty of active filter.

The object of the present invention is achieved like this: this Fault Locating Method comprises the following steps:

Step one: analog signals collection, including the three-phase primary voltage e of three-level three-phase four-wire system active filter_A、 e_B、e_C, three-phase exports electric current i_A、i_B、i_C, DC bus-bar voltage, described DC bus-bar voltage includes Up Highway UHW voltage u_dc1Under with Busbar voltage u_dc2, and current in middle wire i_N；

Step 2: when fault does not occur, the control pulse S according to active filter_xState, this S_xState can Directly read by controller and obtain, and the DC bus-bar voltage signal that step one gathers extrapolates the output of active filter three-phase Point X is for the current potential V of active filter dc bus midpoint M_XM, i.e. V_AM、V_BM、V_CM, wherein X=A or B or C；

Step 3: the part signal being gathered according to step one, substitutes into formula

$V_{XM}^C=i_X\·r_X+L_X\·\frac{{\mathrm{di}}_X}{dt}+e_X-L_N\·\frac{{\mathrm{di}}_N}{dt}-i_N\·r_N$

Obtain the actual potential for active filter dc bus midpoint M for the active filter three-phase output point X respectivelyI.e.It (is called for short)；

Step 4: with the V in step 2_XMWith in step 3Do difference, obtain the potential errors to M point for the X point

Step 5: when fault has occurred and that, by loop analysis during three level active wave filter IGBT faults, can To dope the X point of X corresponding brachium pontis when certain IGBT the breaks down prediction current potential to M pointSpecificallyUnder can passing through Formula obtains:

$V_{XM}^{*}=\left\{\begin{array}{cc}{V}_{XM}^{\′}& \left|i_X\right|>\mathrm{\ϵ}\\ e_X-\frac{2}{3}\underset{i\∈\{A,B,C\}}{\underset{i\≠X}{\Σ}}{e}_i+\frac{1}{3}\underset{i\∈\{A,B,C\}}{\underset{i\≠X}{\Σ}}{V}_{iM}& \left|i_X\right|\≤\mathrm{\ϵ}\end{array}\right..$

Here ε take very little on the occasion of；V′_XMCan be obtained by following table；

Step 6: with the V in step 2_XMWith in step 5Do difference, obtain the potential errors current potential to M point for the X point

Step 7: by step 4 gainedWith step 6 gainedCarry out digital high frequency filtering process, filter High-frequency noise；ObtainWith

Step 2 is explained further to step 7 process:WithIt is to utilize two kinds of different methods The X point obtaining is to the error level of M point；12 results altogether, respectively 12 of corresponding three level active wave filters IGBT, i.e. A phaseB phase C phaseOne has 3 results, respectively corresponding three level Active filter three-phase A, B, C brachium pontis

Step 8: set threshold value λ, λ is volt according to concrete systematic parameter value, unit, and λ takes the dc bus of default The 25% of magnitude of voltage；And judge three of step 7 gainedIt whether is more than threshold value λ；If In three, certain is more than threshold value λ, then this phase there occurs IGBT open fault；

Step 9: determine that in mutually concrete 4 IGBT of ore deposit barrier, which there occurs open fault；

In step 8More than threshold value λ, then there is IGBT open fault in A phase；Now step 7 gained In A phaseUpgrade to characteristic vector；WillWith Do similarity comparison respectively, similarity i.e. corresponding this brachium pontis IGBT fault the highest Particular location；IfWithSimilarity is the highest, then 1 pipe generation open fault of this brachium pontis；Other fault electricity Position is by that analogy.

Beneficial effect, owing to have employed said method, IGBT open fault is accurately positioned, and not defeated by active filter Go out the size of electric current, shape, the restriction of frequency, be not only applicable to various load feelings such as perception, capacitive, resistive and harmonic wave Condition, stands good when three-phase current unbalance, and remains to detect fault and not in the transient state engineering of load changing Fault can be reported by mistake.Method for diagnosing faults belongs to the category carrying out failure judgement according to voltage, but unlike conventional voltage diagnostic method Need to add extra hardware device, thus without the extra hardware cost of introducing.Solve the power of existing active filter Device fault judges the very big problem of difficulty, has reached the purpose of the present invention.

Advantage: 1) independent of load type.I.e. being applicable to various loadtype, no matter active filter compensates Electric current is capacitive, perception or harmonic wave, and this patent method is all suitable for, and conventional method can not have both.2) in load changing situation Under still can with Precise Diagnosis and also fault will not be reported by mistake, conventional method much all can not solve the wrong diagnosis problem of load changing. 3) when three-phase current unbalance, still may determine that fault.4) accuracy is high, and this patent method detection process introduces height Frequency filtering link, eliminates noise jamming, and the fault signature similarity difference tried to achieve is very big, the corresponding phase of abort situation IGBT It is easy to be screened like degree.5) extra hardware cost is not needed.Do not need to add extra sensor.

Brief description:

When Fig. 1 is the A phase 1 pipe IGBT fault of the present invention, 4 IGBT are corresponding for A phaseWaveform.

When Fig. 2 is the A phase 1 pipe IGBT fault of the present invention, A phase current waveform,Waveform,Waveform and Judge signal.

When Fig. 3 is the A phase 2 pipe IGBT fault of the present invention, 4 IGBT are corresponding for A phaseWaveform.

When Fig. 4 is the A phase 2 pipe IGBT fault of the present invention, A phase current waveform,Waveform,Waveform and Judge signal.

Fig. 5 is similarity comparison during 12 IGBT fault respectively of the present invention.

Fig. 6 is the three level active filter topologies figures of the present invention.

Fig. 7 is the overall flow figure of the present invention.

Detailed description of the invention

Embodiment 1: this Fault Locating Method comprises the following steps:

Step one: analog signals collection, including the three-phase primary voltage e of three-level three-phase four-wire system active filter_A、 e_B、e_C, three-phase exports electric current i_A、i_B、i_C, DC bus-bar voltage, described DC bus-bar voltage includes Up Highway UHW voltage u_dc1Under with Busbar voltage u_dc2, and current in middle wire i_N；

Step 2: when fault does not occur, the control pulse S according to active filter_xState, this S_xState can Directly read by controller and obtain, and the DC bus-bar voltage signal that step one gathers extrapolates the output of active filter three-phase Point X is for the current potential V of active filter dc bus midpoint M_XM, i.e. V_AM、V_BM、V_CM, wherein X=A or B or C；

Step 3: the part signal being gathered according to step one, substitutes into formula

$V_{XM}^C=i_X\·r_X+L_X\·\frac{{\mathrm{di}}_X}{dt}+e_X-L_N\·\frac{{\mathrm{di}}_N}{dt}-i_N\·r_N$

Obtain the actual potential for active filter dc bus midpoint M for the active filter three-phase output point X respectivelyI.e.It (is called for short)；

Step 4: with the V in step 2_XMWith in step 3Do difference, obtain the potential errors to M point for the X point

Step 5: when fault has occurred and that, by loop analysis during three level active wave filter IGBT faults, can To dope the X point of X corresponding brachium pontis when certain IGBT the breaks down prediction current potential to M pointSpecificallyUnder can passing through Formula obtains:

$V_{XM}^{*}=\left\{\begin{array}{cc}{V}_{XM}^{\′}& \left|i_X\right|>\mathrm{\ϵ}\\ e_X-\frac{2}{3}\underset{i\∈\{A,B,C\}}{\underset{i\≠X}{\Σ}}{e}_i+\frac{1}{3}\underset{i\∈\{A,B,C\}}{\underset{i\≠X}{\Σ}}{V}_{iM}& \left|i_X\right|\≤\mathrm{\ϵ}\end{array}\right..$

Here ε take very little on the occasion of；V′_XMCan be obtained by following table；

Step 6: with the V in step 2_XMWith in step 5Do difference, obtain the potential errors current potential to M point for the X point

Step 7: by step 4 gainedWith step 6 gainedCarry out digital high frequency filtering process, filter High-frequency noise；ObtainWith

Step 2 is explained further to step 7 process:WithIt is to utilize two kinds of different methods The X point obtaining is to the error level of M point；12 results altogether, respectively 12 of corresponding three level active wave filters IGBT, i.e. A phaseB phase C phaseOne has 3 results, respectively corresponding three level Active filter three-phase A, B, C brachium pontis

Step 8: set threshold value λ, λ is volt according to concrete systematic parameter value, unit, and λ takes the dc bus of default The 25% of magnitude of voltage；And judge three of step 7 gainedIt whether is more than threshold value λ；If In three, certain is more than threshold value λ, then this phase there occurs IGBT open fault；

Step 9: determine that in concrete 4 IGBT of fault phase, which there occurs open fault；

In step 8More than threshold value λ, then there is IGBT open fault in A phase；Now step 7 gained In A phaseUpgrade to characteristic vector；WillWith Do similarity comparison respectively, similarity i.e. corresponding this brachium pontis IGBT fault the highest Particular location；IfWithSimilarity is the highest, then 1 pipe generation open fault of this brachium pontis；Other fault potentials By that analogy.

Overall flow figure is as shown in Figure 7.

Fig. 1 and Fig. 2 shows waveform when A phase 1 pipe breaks down.Fig. 1 is corresponding Four waveforms, just this four waveforms be used for andMake comparisons, see four waveforms Who andSimilarity is the highest.Fig. 2 showsElectric current and judge signal waveform.Can be seen thatSimilarity is very high, and therefore corresponding 1 pipe fault is positioned.

Fig. 3 and Fig. 4 shows waveform when A phase 2 pipe breaks down.Fig. 3 is corresponding Four waveforms, just this four waveforms be used for andMake comparisons, see four ripples Shape who andSimilarity is the highest.Fig. 4 showsElectric current and judge signal waveform.Can see Go outSimilarity is very high, and therefore corresponding 2 pipe faults are positioned.

The fault waveform of other 10 IGBT is similar with determination methods, no longer describes in detail.12 IGBT open faults are corresponding Similarity Measure result is as shown in Figure 5.Similarity maximum is the IGBT of corresponding open fault.

Claims (1)

1. a three level active wave filter IGBT open fault localization method, is characterized in that: this Fault Locating Method include with Lower step:

Step one: analog signals collection, including the three-phase primary voltage e of three-level three-phase four-wire system active filter_A、e_B、 e_C, three-phase exports electric current i_A、i_B、i_C, DC bus-bar voltage, described DC bus-bar voltage includes Up Highway UHW voltage u_dc1With lower mother Line voltage u_dc2, and current in middle wire i_N；

Step 2: when fault does not occur, the control pulse S according to active filter_xState, and step one gather DC bus-bar voltage signal extrapolates the current potential for active filter dc bus midpoint M for the active filter three-phase output point X V_XM, i.e. V_AM、V_BM、V_CM, wherein X=A or B or C；

Step 3: the part signal being gathered according to step one, substitutes into formula

$V_{XM}^C=i_X\·r_X+L_X\·\frac{{\mathrm{di}}_X}{dt}+e_X-L_N\·\frac{{\mathrm{di}}_N}{dt}-i_N\·r_N$

Obtain the actual potential for active filter dc bus midpoint M for the active filter three-phase output point X respectively I.e.It (is called for short)；

Step 4: with the V in step 2_XMWith in step 3Do difference, obtain the potential errors to M point for the X point

Step 5: when fault has occurred and that, by loop analysis during three level active wave filter IGBT faults, can be pre- Measure the X point of X corresponding brachium pontis when certain IGBT the breaks down prediction current potential to M pointSpecificallyCan be obtained by following formula :

$V_{XM}^{*}=\left\{\begin{array}{cc}{V}_{XM}^{\′}& \left|i_X\right|>\mathrm{\ϵ}\\ e_X-\frac{2}{3}\underset{i\∈\left\{A,B,C\right\}}{\underset{i\≠X}{\mathrm{\Σ}}}{e}_i+\frac{1}{3}\underset{i\∈\left\{A,B,C\right\}}{\underset{i\≠X,}{\mathrm{\Σ}}}{V}_{iM}& \left|i_X\right|\≤\mathrm{\ϵ}\end{array}\right..$

Here ε take very little on the occasion of；V ' therein_XMCan be obtained by following table；

Step 6: with the V in step 2_XMWith in step 5Do difference, obtain the potential errors current potential to M point for the X point

Step 7: by step 4 gainedWith step 6 gainedCarry out digital high frequency filtering process, filter high frequency Noise；ObtainWith

Step 2 is explained further to step 7 process:WithIt is the X utilizing two kinds of different methods to obtain Point is to the error level of M point；12 results altogether, respectively 12 IGBT of corresponding three level active wave filters, i.e. A phase 'sB phase C phase 's One has 3 results, respectively corresponding three level active filters Ripple device three-phase A, B, C brachium pontis

Step 8: set threshold value λ, λ is volt according to concrete systematic parameter value, unit, and λ takes the DC bus-bar voltage of default The 25% of value；And judge three of step 7 gainedIt whether is more than threshold value λ；If three In certain be more than threshold value λ, then this phase there occurs IGBT open fault；

Step 9: determine that in concrete 4 IGBT of fault phase, which there occurs open fault；

In step 8More than threshold value λ, then there is IGBT open fault in A phase；Now step 7 gainedIn A PhaseUpgrade to characteristic vector；WillWith Do similarity comparison respectively, similarity i.e. corresponding this brachium pontis IGBT fault the highest Particular location；IfWithSimilarity is the highest, then 1 pipe generation open fault of this brachium pontis；Other fault electricity Position is by that analogy.