CN105842577A - Power converter open-circuit fault diagnosis method in AC variable-frequency speed regulation system - Google Patents

Abstract

The invention discloses a power converter open-circuit fault diagnosis method in a variable-frequency speed regulation system. The power converter open-circuit fault diagnosis method comprises the steps of determining an array length sampled in a complete current period according to a preset speed; calculating the variance of a three-phase current sampling array, thereby determining a relative variance; calculating bias of the three-phase current sampling array; determining whether an open-circuit fault occurs through comparing the relative variance with two thresholds and a faulted leg when the fault occurs; and if single-tube open-circuit fault occurs, determining a fact that the fault occurs on an upper tube or a lower tube through the bias. According to the power converter open-circuit fault diagnosis method, through determining the length L of the periodical current signal array, calculating the variances Var of the three current sampling arrays, and calculating the relative variance epsilonx, whether the fault occurs is determined according to the obtained relative variance epsilonx. When a single-tube fault occurs, the position of the faulted power tube is further determined by means of the bias gammax. The power converter open-circuit fault diagnosis method improves accuracy in determining the fault of the power converter in the AC variable-frequency speed regulation system and furthermore has advantages of simple algorithm and easy realization.

Description

Power inverter open fault diagnostic method in a kind of AC variable-frequency speed regulation system

Technical field

The invention belongs to the technical field of Power Converter faults diagnosis, particularly relate in a kind of AC variable-frequency speed regulation system Power inverter open fault diagnostic method.

Background technology

In fields such as industry manufacture, Aero-Space, transportation, the frequency conversion speed-adjusting system that power inverter drives is with its energy Metric density is big, and efficiency advantages of higher is widely applied.Fig. 1 is traditional three-phase frequency-conversion speed-regulation system and basic structure thereof Figure.Along with these systems are more and more higher to the requirement of safety and reliability, to various parts, especially it is easiest to event The power inverter part of barrier, carries out fault detect and location seems and is even more important.Traditional method for diagnosing faults is broadly divided into Two kinds: one is by increasing sensor, directly detects the conduction voltage drop of power inverter or measures the temperature of power inverter, The system failure can quickly be positioned by this method, and the most this method needs to increase the hardware such as sensor, is carrying out merit The expense of system is added while rate pipe fault diagnosis；Two is to utilize existing sensor resource in frequency conversion speed-adjusting system, logical Cross the method that after comparing fault, correlated characteristic signal carries out fault diagnosis and location with deviation value under normal circumstances.At the second In algorithm, the most conventional has method for diagnosing faults based on intelligent classification, but erroneous judgement easily occurs in this method, its application Occasion is limited, and slightly aobvious complexity, need substantial amounts of data to be trained；Next to that utilize correlation coefficient, Euclidean distance, vector When angle cosine and Hausdorff distance scheduling algorithm carry out fault diagnosis, the most aobvious complexity of these methods, and in reality In application too many due to shared processor resource, it is achieved get up not uneconomical.

Summary of the invention

For the disadvantages described above of prior art, the technical problem to be solved of the present invention is to provide a kind of AC frequency conversion Power inverter open fault diagnostic method in governing system, by analyze under normal condition with the electric current probability under malfunction Density curve is distributed, and utilizes the variance of current sample sequence and the degree of bias to carry out the measure of similarity, more easily solves Diagnosis problem during frequency conversion speed-adjusting system power inverter generation open fault.

The present invention provides power inverter open fault diagnostic method in a kind of AC variable-frequency speed regulation system, including following step Rapid:

S1, determine the length of periodic current signal array, useRepresent, wherein T_sIt is adopting of controller In the sample cycle, p is the number of pole-pairs of motor, ω^*It is the speed of motor；

S2, in each sampling instant, write down current flow sampled value, obtain three current sample arrays A (L), B (L), C (L)；Calculate variance Var of three current sample arrays_x=σ²=EX²-μ², wherein { a, b, c} represent a, b, c tri-to x ∈ respectively Phase, X is in three current sample arrays；Then contra extent is calculated

S3, the degree of bias of three current sample arrays of calculatingWherein x ∈ {a,b,c}；

S4, relative variance ε according to gained_xJudge whether faulty generation, if faulty generation, also to judge event accordingly Brachium pontis and fault type that barrier occurs are single tube fault or two-tube fault；When there is single tube fault, then utilize degree of bias γ_xEnter The position of one step failure judgement power tube.

Further, in described step S4: according to the relative variance calculated, then have

$f_l=\left\{\begin{array}{cc}0,& {\mathrm{\&epsiv;}}_x\&ap;{\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\\ 1,& \left\{\begin{array}{c}{P}_1<{\mathrm{\&epsiv;}}_x<P_2\\ {\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\end{array}\right.\\ 2,& \left\{\begin{array}{c}{\mathrm{\&epsiv;}}_x<P_1\\ {\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\end{array}\right.\end{array}\right.$

If f_lValue is 0, then x phase is healthy；If 1, then x phase has a pipe fault；If 2, then x phase has two fault pipes； If there being a power tube fault, then utilize degree of bias γ_xDetermine whether location of fault；

$f_s=\left\{\begin{array}{cc}1,& {\mathrm{\&gamma;}}_x<0\\ 0,& {\mathrm{\&gamma;}}_x>0\end{array}\right.$

Work as f_sValue is 0, then x phase down tube fault, works as f_sValue is 1, then pipe fault in x phase, thereby determines that the position that fault occurs Put.

In general, by the contemplated above technical scheme of the present invention compared with prior art, there is following useful effect Really:

In the AC variable-frequency speed regulation system of the present invention, power inverter open fault diagnostic method is determined by periodically electricity Length L of stream signal array, calculates variance Var of three current sample arrays, then calculates contra extent ε_x, root Relative variance ε according to gained_xJudging whether faulty generation, when there is single tube fault, then utilizing degree of bias γ_xDetermine whether The position of fault power pipe, improves the accuracy of the fault diagnosis of AC variable-frequency speed regulation system power inverter, and algorithm Simply, it is easy to accomplish.

Accompanying drawing explanation

Fig. 1 is traditional three-phase frequency-conversion speed-regulation system and basic block diagram thereof.

Fig. 2 be the present invention AC variable-frequency speed regulation system in the FB(flow block) of power inverter open fault diagnostic method.

Detailed description of the invention

Describing the detailed description of the invention of the present invention below in conjunction with the accompanying drawings in detail, it, as the part of this specification, passes through Embodiment illustrates the principle of the present invention, and other aspects of the present invention, feature and advantage thereof will be become by this detailed description Very clear.In the accompanying drawing of institute's reference, in different figures, same or analogous parts use identical drawing reference numeral to represent. For making the present invention easier to understand, the specific embodiment of the present invention is further illustrated below.

As in figure 2 it is shown, power inverter open fault diagnostic method in the AC variable-frequency speed regulation system of the present invention, including with Lower step:

S1, determine the length of periodic current signal array, useRepresent, wherein T_sIt is adopting of controller In the sample cycle, p is the number of pole-pairs of motor, ω^*It is the speed of motor.

S2, in each sampling instant, write down current flow sampled value, obtain three current sample arrays A (L), B (L), C (L)；Calculate variance Var of three current sample arrays_x=σ²=EX²-μ², wherein { a, b, c} represent a, b, c tri-to x ∈ respectively Phase, X is in three current sample arrays；Then contra extent is calculated

S3, the degree of bias of three current sample arrays of calculatingWherein x ∈ { a, b, c} utilize formulaCalculate the size of the current sample sequence degree of bias.

S4, relative variance ε according to gained_xJudge whether faulty generation, if faulty generation, also to judge event accordingly Brachium pontis and fault type that barrier occurs are single tube fault or two-tube fault；When there is single tube fault, then utilize degree of bias γ_xEnter The position of one step failure judgement power tube.

According to the relative variance calculated, then have

$f_l=\left\{\begin{array}{cc}0,& {\mathrm{\&epsiv;}}_x\&ap;{\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\\ 1,& \left\{\begin{array}{c}{P}_1<{\mathrm{\&epsiv;}}_x<P_2\\ {\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\end{array}\right.\\ 2,& \left\{\begin{array}{c}{\mathrm{\&epsiv;}}_x<P_1\\ {\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\end{array}\right.\end{array}\right.$

If f_lValue is 0, then x phase is healthy；If 1, then x phase has a pipe fault；If 2, then x phase has two fault pipes. If there being a power tube fault, then utilize degree of bias γ_xDetermine whether location of fault

$f_s=\left\{\begin{array}{cc}1,& {\mathrm{\&gamma;}}_x<0\\ 0,& {\mathrm{\&gamma;}}_x>0\end{array}\right.$

Work as f_sValue is 0, then x phase down tube fault, works as f_sValue is 1, then pipe fault in x phase.Thereby determine that the position that fault occurs It is T₁,T₂,T₃,T₄,T₅,T₆In which one or two, be shown in Table I.

Table I is the fault type table of detection method.

Table I

The present invention, according to speed preset, determines the array length of a full current periodic sampling；Calculating three-phase current is adopted The variance of sample array, and determine relative variance with this；Calculate the degree of bias of three current sample arrays；By relative variance and two threshold values The brachium pontis of guilty culprit when contrast determines whether open fault occurs and breaks down；If there is single tube open fault, the most again root Determine that fault is upper pipe or down tube according to the degree of bias.

In the AC variable-frequency speed regulation system of the present invention, power inverter open fault diagnostic method is determined by periodically electricity Length L of stream signal array, calculates variance Var of three current sample arrays, then calculates contra extent ε_x, root Relative variance ε according to gained_xJudging whether faulty generation, when there is single tube fault, then utilizing degree of bias γ_xDetermine whether The position of fault power pipe, improves the accuracy of the fault diagnosis of AC variable-frequency speed regulation system power inverter, and algorithm Simply, it is easy to accomplish.

Claims (2)

1. power inverter open fault diagnostic method in an AC variable-frequency speed regulation system, it is characterised in that include following step Rapid:

S1, determine the length of periodic current signal array, useRepresent, wherein T_sIt it is the sampling week of controller Phase, p is the number of pole-pairs of motor, ω^*It is the speed of motor；

S2, in each sampling instant, write down current flow sampled value, obtain three current sample arrays A (L), B (L), C (L)； Calculate variance Var of three current sample arrays_x=σ²=EX²-μ², wherein { a, b, c} represent a, b, c three-phase to x ∈ respectively, and X is In three current sample arrays one；Then contra extent is calculated

S3, the degree of bias of three current sample arrays of calculatingWherein x ∈ a, b, c}；

S4, relative variance ε according to gained_xJudge whether faulty generation, if faulty generation, also failure judgement to send out accordingly Raw brachium pontis and fault type are single tube fault or two-tube fault；When there is single tube fault, then utilize degree of bias γ_xFurther The position of failure judgement power tube.

Power inverter open fault diagnostic method in AC variable-frequency speed regulation system the most according to claim 1, its feature It is, in described step S4: according to the relative variance calculated, then have

$f_l=\left\{\begin{array}{cc}0,& {\mathrm{\&epsiv;}}_x\&ap;{\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\\ 1,& \left\{\begin{array}{c}{P}_1<{\mathrm{\&epsiv;}}_x<P_2\\ {\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\end{array}\right.\\ 2,& \left\{\begin{array}{c}{\mathrm{\&epsiv;}}_x<P_1\\ {\mathrm{\&epsiv;}}_y\&ap;{\mathrm{\&epsiv;}}_z\&ap;1\end{array}\right.\end{array}\right.$

If f_lValue is 0, then x phase is healthy；If 1, then x phase has a pipe fault；If 2, then x phase has two fault pipes；If having one Individual power tube fault, then utilize degree of bias γ_xDetermine whether location of fault；

$f_s=\left\{\begin{array}{cc}1,& {\mathrm{\&gamma;}}_x<0\\ 0,& {\mathrm{\&gamma;}}_x>0\end{array}\right.$

Work as f_sValue is 0, then x phase down tube fault, works as f_sValue is 1, then pipe fault in x phase, thereby determines that the position that fault occurs.