Power converter, anomaly detection device, and anomaly detection method

Abstract

To appropriately detect an abnormality of a current detector.SOLUTION: An abnormality determination unit 51b is provided with: an original abnormality degree calculation unit 516; a first current estimation unit 517-1; a first abnormality degree calculation unit 518-1 which generates first abnormality degree estimation values AU1, AV1, AW1 representing an abnormality degree of each of a plurality of current detectors on the basis of first current estimation values IU1, IV1, IW1 in a plurality of phases; and a first abnormality degree correction unit 519-1 which generates first predicted abnormality degrees AU1C, AV1C, AW1C representing an abnormality degree of each of the plurality of current detectors on the basis of original abnormality degree calculation values AU0, AV0, AW0 and the first abnormality degree estimation values AU1, AV1, AW1.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a power conversion device, an anomaly detection device, and an anomaly detection method. [Background technology]

[0002] The following patent documents 1 to 3 describe techniques for detecting abnormalities in current detectors. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 3737370 [Patent Document 2] Japanese Patent Publication No. 2005-94912 [Patent Document 3] Japanese Patent Publication No. 2006-50702 [Overview of the project] [Problems that the invention aims to solve]

[0004] By the way, in the technology described above, there is a desire to detect abnormalities in the current detector more accurately. This invention has been made in view of the circumstances described above, and aims to provide a power conversion device, an abnormality detector, and an abnormality detection method that can appropriately detect abnormalities in a current detector. [Means for solving the problem]

[0005] To solve the above problems, the power conversion device of the present invention is a power conversion device provided between an AC power source and a load device, comprising: a plurality of current detectors that detect a plurality of phase AC currents flowing between the AC power source and the power conversion device, or between the power conversion device and the load device, for each phase; and an abnormality determination device that determines an abnormality of the current detectors, wherein the abnormality determination device comprises: a primary abnormality calculation unit that generates a primary abnormality calculation value representing the degree of abnormality of each of the plurality of current detectors based on the current detection values ​​of the plurality of phases detected by the current detectors; a first current estimation unit that calculates a first current estimation value for the plurality of phases based on the primary abnormality calculation value and the current detection values ​​of the plurality of phases; a first abnormality calculation unit that generates a first abnormality estimation value representing the degree of abnormality of each of the plurality of current detectors based on the first current estimation value for the plurality of phases; and a first abnormality correction unit that generates a first predicted abnormality value representing the degree of abnormality of each of the plurality of current detectors based on the primary abnormality calculation value and the first abnormality estimation value. [Effects of the Invention]

[0006] According to the present invention, abnormalities in the current detector can be appropriately detected. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of the configuration of a power conversion device according to the first embodiment. [Figure 2] This is a diagram showing an example of the detailed configuration of a power conversion device. [Figure 3] This is a block diagram of an AC / DC converter. [Figure 4] This is a block diagram of a DC / AC converter. [Figure 5] This is a block diagram of the inverter-side abnormality detection unit in the first embodiment. [Figure 6] This is a block diagram showing the details of the original abnormality calculation unit. [Figure 7] This is a block diagram of a computer. [Figure 8]This flowchart shows an example of the abnormality detection process in the inverter-side abnormality detection unit. [Figure 9] This is a circuit diagram of the load device and other components applied to the simulation. [Figure 10] This figure shows an example of the simulation results. [Figure 11] This figure shows another example of the simulation results. [Figure 12] This is a block diagram of the inverter-side abnormality detection unit in the second embodiment. [Figure 13] This is a block diagram of the inverter-side abnormality detection unit in the third embodiment. [Figure 14] This figure shows an example of the simulation results in the third embodiment. [Figure 15] This figure shows another example of the simulation results according to the third embodiment. [Figure 16] This figure shows an example of the configuration of a power conversion device according to the fourth embodiment. [Figure 17] This is a block diagram of the converter-side output estimator and the inverter-side output estimator in the fourth embodiment. [Modes for carrying out the invention]

[0008] [Summary of the Embodiment] The following methods can be considered as techniques for verifying the integrity of a current detector that detects the current flowing between a power converter and a load device. For example, by applying the technology described in Patent Document 1, it is possible to detect the current of each phase flowing between the power converter and the load device, and to determine the phase in which an abnormality has occurred by comparing the effective current value of each phase with the effective current value of the other phases. In other words, according to this technology, it is possible to determine the phase of the current detector in which an abnormality has occurred when a balanced three-phase load is connected to a three-phase three-wire output.

[0009] However, if an unbalanced three-phase load is connected to a three-phase three-wire output, more current will flow to the phase with the smaller load, resulting in a mismatch in the three-phase RMS current values. Alternatively, if at least one single-phase connected load is connected to a three-phase three-wire output, more current will flow to the phase with the smaller load, resulting in a mismatch in the three-phase RMS current values. For example, in the case of an uninterruptible power supply (UPS) application, if at least one single-phase connected load is connected and the three-phase RMS current values ​​become mismatched, there is a risk of false detection of an abnormality even if the current detector is functioning correctly.

[0010] Furthermore, by applying the technologies described in Patent Documents 2 and 3, it is possible to determine whether the sum of the three-phase current detection values ​​is zero, and if the sum of the three-phase currents is not zero, it is possible to determine which phase has an abnormality in the current detector by comparing the current values ​​of each phase or determining the sign. However, Patent Documents 2 and 3 do not specifically show a technology for quantitatively detecting the degree of abnormality in the current detector when the load connected to the three-phase three-wire output is unbalanced. Therefore, the embodiment described later aims to appropriately detect abnormalities in the current detector even when the load is unbalanced.

[0011] [First Embodiment] <Configuration of the first embodiment> Embodiments of the present invention will be described below with reference to the drawings. The embodiments are illustrative examples for explaining the present invention, and have been omitted and simplified as appropriate for clarity of explanation. Furthermore, not all of the elements and their combinations described in the embodiments are necessarily essential to the solution of the invention. When there are multiple components having the same or similar functions, the same reference numeral may be used with different subscripts in the description. Also, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description.

[0012] Figure 1 shows an example of the configuration of the power converter 100 according to the first embodiment. In Figure 1, the power conversion device 100 includes a power conversion unit 3, AC wiring 11, 12, 13, AC wiring 21, 22, 23, current detectors 14, 15, 16, current detectors 24, 25, 26, a control device 41, a pulse generator 42, an anomaly detection device 51, and a display device 52 (information display unit).

[0013] The power converter 100 receives AC power from the AC power source 1 via AC wiring 11, 12, and 13, performs power conversion using the power conversion unit 3, and outputs the converted AC power to the load device 2 via AC wiring 21, 22, and 23. In other words, the power converter 100 converts the AC voltage input from the AC power source 1 into other AC voltages with different voltages and frequencies and applies them to the load device 2. Current detectors 14, 15, and 16 detect the currents in the AC wiring 11, 12, and 13, respectively, i.e., the R phase, S phase, and T phase currents, and the resulting current detection value I R ,I S ,I T This is supplied to the control device 41 and the anomaly detection unit 51.

[0014] Current detectors 24, 25, and 26 detect the currents of the AC wiring 21, 22, and 23, respectively, i.e., the U-phase, V-phase, and W-phase currents, and the resulting current detection value I U ,I V ,I W This is supplied to the control device 41 and the abnormality detection unit 51. The control device 41 outputs an AC voltage command value for the output voltage of the power conversion unit 3 to the pulse generator 42. Based on this AC voltage command value, the pulse generator 42 generates pulse signals to control the on / off state of each switching element, etc. (not shown) in the power conversion unit 3, and outputs the generated pulse signals to the power conversion unit 3.

[0015] Figure 2 shows an example of the detailed configuration of the power converter 100. In FIG. 2, the power conversion unit 3 includes a converter unit 3a and an inverter unit 3b. The converter unit 3a converts the input AC voltage into a DC voltage and outputs it via DC wirings 31 and 32. The inverter unit 3b converts the DC voltage input via the DC wirings 31 and 32 into an AC voltage.

[0016] However, the configuration of the illustrated power conversion unit 3 is merely an example and is not necessarily limited to the illustrated configuration. For example, the number of the DC wirings 31 and 32 is not necessarily two, and in the case of a three-level converter, the number of DC wirings is three. Further, the power conversion unit 3 may convert an AC voltage into another AC voltage without passing through a DC voltage, such as a cycloconverter.

[0017] Further, the control device 41 includes a converter control section 41a and an inverter control section 41b. Further, the pulse generator 42 includes a converter-side pulse generation section 42a and an inverter-side pulse generation section 42b. Further, the abnormality determination device 51 includes a converter-side abnormality determination section 51a and an inverter-side abnormality determination section 51b. Further, the display 52 includes a converter-side display section 52a and an inverter-side display section 52b.

[0018] The current detection values I R , I S , I T detected by the current detectors 14, 15, and 16 are input to the converter control section 41a and the converter-side abnormality determination section 51a. The converter control section 41a outputs a DC voltage command value for commanding the DC voltage that the converter unit 3a should output to the converter-side pulse generation section 42a. The converter-side pulse generation section 42a generates a pulse signal for on / off control of each switching element (not shown) in the converter unit 3a based on this DC voltage command value, and outputs the generated pulse signal to the converter unit 3a.

[0019] Similarly, the current detection values I U , I V , IW This is input to the inverter control unit 41b and the inverter-side abnormality detection unit 51b. The inverter control unit 41b outputs an AC voltage command value to the inverter-side pulse generation unit 42b, which commands the AC voltage that the inverter unit 3b should output. Based on this AC voltage command value, the inverter-side pulse generation unit 42b generates pulse signals to control the on / off state of each switching element, etc. (not shown) in the inverter unit 3b, and outputs the generated pulse signals to the inverter unit 3b.

[0020] The converter-side abnormality detection unit 51a detects the current detection value I R ,I S ,I T Based on this, it is determined whether or not an abnormality has occurred in any of the current detectors 14, 15, or 16, and the result is displayed on the converter-side display unit 52a. Similarly, the inverter-side abnormality determination unit 51b determines whether or not an abnormality has occurred in the current detection value I U ,I V ,I W Based on this, it is determined whether or not there is an abnormality in any of the current detectors 24, 25, or 26, and the result is displayed on the converter-side abnormality determination unit 51a. In order to determine whether or not there is an abnormality in these current detectors, it is desirable that the AC power supply 1 and the load device 2 have their neutral points not grounded.

[0021] As described above, the power converter 100 converts the AC voltage input from the AC power source 1 into another AC voltage with a different voltage and frequency and applies it to the load device 2. Here, as in the example shown in Figure 2, if the power conversion unit 3 comprises a converter unit 3a, an inverter unit 3b, and DC wiring 31, 32, the power converter 100 can be separated into an AC / DC converter 100a (see Figure 3) and a DC / AC converter 100b (see Figure 4).

[0022] Figure 3 is a block diagram of the AC / DC converter 100a. As shown in the figure, the AC / DC converter 100a includes a converter unit 3a, AC wiring 11, 12, 13, current detectors 14, 15, 16, a converter control unit 41a, a converter-side pulse generation unit 42a, a converter-side abnormality detection unit 51a, and a converter-side display unit 52a.

[0023] Figure 4 is a block diagram of the DC / AC converter 100b. As shown in the figure, the DC / AC converter 100b comprises an inverter unit 3b, AC wiring 21, 22, 23, current detectors 24, 25, 26, an inverter control unit 41b, an inverter-side pulse generation unit 42b, an inverter-side abnormality detection unit 51b, and an inverter-side display unit 52b.

[0024] Each element in Figures 3 and 4 is the same as that shown in Figure 2. As shown in Figures 3 and 4, the AC / DC converter 100a and the DC / AC converter 100b can be independent devices. Therefore, depending on the application, either only the AC / DC converter 100a or only the DC / AC converter 100b may be provided.

[0025] In the following explanation, we will mainly describe the configuration and operation of the inverter-side abnormality detection unit 51b in the DC / AC converter 100b, but the configuration and operation of the converter-side abnormality detection unit 51a in the AC / DC converter 100a are the same as those of the inverter-side abnormality detection unit 51b.

[0026] <Various parameters, etc.> (Detection gain G U ,G V ,G W ) Next, the various parameters in this embodiment will be described. Current detection value I from current detectors 24, 25, and 26 U ,I V ,I W and true current I UT ,I VT ,I WTThe relationship can be expressed by the following equations (1) to (3). Note that G U , G V , G W This represents the detection gain in current detectors 24, 25, and 26. I U =I UT ×G U …(1) I V =I VT ×G V …(2) I W =I WT ×G W …(3) Therefore, in this embodiment, these detection gains G U ,G V ,G W By detecting abnormalities in the current detectors 24, 25, 26, etc., abnormalities are detected. Also, the actual value of the current flowing I UT ,I VT ,I WT Regarding this, the following equation (4) holds true from Kirchhoff's current law. I UT +I VT +I WT =0 …(4)

[0027] (Absolute abnormality level A) U ,A V ,A W ) Here, as information indicating the absolute degree of abnormality of current detectors 24, 25, and 26, absolute abnormality A U ,A V ,A W We will implement this. Absolute Abnormality Level A U ,A V ,A W The detection gain G U ,G V ,G W It is defined such that the following equations (5) to (7) hold. G U =1+A U …(5) G V =1+AV …(6) G W =1 + A W …(7)

[0028] Absolute abnormality degree A U , A V , A W When A is 0, the corresponding detection gain G U , G V , G W becomes "1", indicating that the current detectors 24, 25, and 26 are normal. On the other hand, when the absolute abnormality degree A U , A V , A W is a value other than 0, the corresponding detection gain G U , G V , G W becomes a value other than "1", indicating that the current detectors 24, 25, and 26 are abnormal. Therefore, the absolute abnormality degree A U , A V , A W is information representing the degree of abnormality, that is, the greater the deviation of these values from "0", the greater the influence of the abnormality.

[0029] Absolute abnormality degree A U , A V , A W Using it, the current detection values I shown by the above formulas (1) to (3) U , I V , I W are represented by the following formulas (8) to (10). I U = I UT × (1 + A U ) …(8) I V = I VT × (1 + A V ) …(9) I W = I WT × (1 + A W ) …(10)

[0030] Here, when all of the current detectors 24, 25, and 26 for the U-phase, V-phase, and W-phase are normal, "G U = G V = GW Since = 1, the following equation (11) holds. G U +G V +G W =3 …(11) On the other hand, if one of the current detectors 24, 25, or 26 is abnormal, then "G U ≠1 and G V =G W =1", G V ≠1 and G U =G W =1" and "G W ≠1 and G U =G V Since either "=1" or "G" is true, equation (11) does not hold, and therefore "G U +G V +G W ≠3.

[0031] Furthermore, if two or three of the current detectors 24, 25, and 26 are abnormal, "G U +G V +G W =3" or "G U +G V +G W Either ≠3 is true. U +G V +G W The value "=3" holds true when the deviation from "1" cancels out for the detection gain of the abnormal current detector. If the deviations do not cancel each other out, then "G U +G V +G W ≠3.

[0032] (Relative detection gain G) U0 ,G V0 ,G W0 ) Here, the relative detection gain G such that the sum of the gains is always 3. U0 ,G V0 ,G W0 and variable B I We will introduce a new feature. Relative detection gain G U0 ,G V0 ,G W0 and variable BI This is a quantity set such that the following equations (12), (13) to (15) hold true. G U0 +G V0 +G W0 =3 …(12) I U =I UT ×B I ×G U0 …(13) I V =I VT ×B I ×G V0 …(14) I W =I WT ×B I ×G W0 …(15)

[0033] From a comparison of equations (1) to (3) and equations (13) to (15), the detection gain G U ,G V ,G W and relative detection gain G U0 ,G V0 ,G W0 The following equations (16) to (18) hold between these two points. G U =B I ×G U0 …(16) G V =B I ×G V0 …(17) G W =B I ×G W0 …(18)

[0034] From the sum of equations (16) to (18), the following equation (19) holds. G U +G V +G W =B I ×(G U0 +G V0 +G W0 ) …(19) Substituting equation (12) into the right-hand side of equation (19) and rearranging, we obtain equation (20). BI =( G U +G V +G W ) / 3 …(20) That is, variable B I This refers to absolute gain G U , G V , G W This is the average value.

[0035] (Relative anomaly A) UR ,A VR ,A WR ) Here, equations (21) to (23) below hold for A. UR ,A VR ,A WR This is called the "relative anomaly." G U0 =1+A UR …(twenty one) G V0 =1+A VR …(twenty two) G W0 =1+A WR …(twenty three) This relative anomaly A UR ,A VR ,A WR Using this, equations (16) to (18) above can be expressed as equations (24) to (26). I U =I UT ×B I ×(1+A UR ) …(twenty four) I V =I VT ×B I ×(1+A VR ) …(twenty five) I W =I WT ×B I ×(1+A WR ) …(26)

[0036] Furthermore, from equations (12) and (21) to (23), relative anomaly A UR ,A VR ,A WR The following equation (27) holds true for the sum of . A UR +A VR +A WR =0 …(27) Therefore, relative anomaly A UR ,A VR ,A WR This refers to the absolute abnormality scale A, which represents the degree of abnormality. U ,A V ,A W It can be said that this is a normalized version such that equation (27) holds true. On the other hand, absolute abnormality A U ,A V ,A W Regarding this, if all current detectors 24, 25, and 26 are functioning normally (i.e., "G U =G V =G W If "=1" is true, then from equations (5) to (7) and equation (11), "A U +A V +A W =0. On the other hand, if one or more of the current detectors 24, 25, and 26 are abnormal, then "A U +A V +A W =0" or "A U +A V +A W It will be either ≠0.

[0037] <Details of each element> (Overview of the inverter-side abnormality detection unit 51b) Figure 5 is a block diagram of the inverter-side abnormality determination unit 51b in the first embodiment. In Figure 5, the inverter-side abnormality determination unit 51b includes a base abnormality calculation unit 516 (base abnormality calculation process), a current estimation unit 517-1 (first current estimation unit, first current estimation process), an abnormality calculation unit 518-1 (first abnormality calculation unit, first abnormality calculation process), an abnormality correction unit 519-1 (first abnormality correction unit, first abnormality correction process), and an abnormality determination unit 514.

[0038] (Original abnormality calculation unit 516) The original abnormality calculation unit 516 calculates the current detection value I U ,IV ,I W Based on the above, the relative anomaly A in equations (24) to (26) UR ,A VR ,A WR The estimated value of the original abnormality calculation A U0 ,A V0 ,A W0 This will be calculated. Details of this calculation method will be described later.

[0039] (Current estimation section 517-1) The current estimation unit 517-1 calculates the original abnormality value A calculated by the original abnormality calculation unit 516. U0 ,A V0 ,A W0 And, current detection value I U ,I V ,I W Based on this, the true value of the current I UT ,I VT ,I WT Current estimate I is an estimated value. U1 ,I V1 ,I W1 The (first current estimate) is calculated. For example, the current estimation unit 517-1 calculates the current estimate I using the following equations (28) to (30). U1 ,I V1 ,I W1 Calculate. I U1 =I U / (1+A U0 ) …(28) I V1 =I V / (1+A V0 ) …(29) I W1 =I W / (1+A W0 ) …(30)

[0040] By the way, the calculated value of the original abnormality A U0 ,A V0 ,A W0 True relative anomaly A UR ,A VR ,A WR If equal to (A U0 =A UR , A V0=A VR , and A W0 =A WR ), then equations (31) to (33) hold. I U1 =I UT ×B I …(31) I V1 =I VT ×B I …(32) I W1 =I WT ×B I …(33) In other words, the calculated value of the original abnormality A U0 ,A V0 ,A W0 and true relative anomaly A UR ,A VR ,A WR If and are equal, then the calculation result of the true value of the current (I) can be obtained using equations (4) and (31) to (33). U1 , I V1 , I W1 Regarding ), the following equation (34), which corresponds to Kirchhoff's current law, also holds. I U1 +I V1 +I W1 =0 …(34) On the other hand, the calculated value of the original abnormality A U0 ,A V0 ,A W0 True relative anomaly A UR ,A VR ,A WR If the situation differs from this (for example, if calculation errors occur due to a three-phase load imbalance), then equation (34) above will no longer hold.

[0041] (Abnormality calculation unit 518-1) The abnormality calculation unit 518-1 calculates the current estimate I U1 ,I V1 ,I W1 Based on the above, the relative anomaly A in equations (24) to (26) UR ,A VR ,A WR An anomaly score A is the estimated result of this estimation. U1 ,A V1,A W1 Output the (first anomaly estimate).

[0042] The original abnormality calculation value A calculated by the original abnormality calculation unit 516 described above. U0 ,A V0 ,A W0 True relative anomaly A UR ,A VR ,A WR If equal to the above, the anomaly estimate A is calculated by the anomaly calculation unit 518-1. U1 ,A V1 ,A W1 In "A U1 =A V1 =A W1 The equation "=0" holds true. Therefore, equation (35) below holds true. |A U0 |+|A V0 |+|A W0 | > |A U1 |+|A V1 |+|A W1 | …(35)

[0043] Original abnormality calculation value A U0 ,A V0 ,A W0 True relative anomaly A UR ,A VR ,A WR If it differs from this, the anomaly estimate A U1 ,A V1 ,A W1 This is the estimated current value I U1 ,I V1 ,I W1 This can be considered as the relative anomaly calculated for the correction error in [the given value]. Therefore, the anomaly estimate A U1 ,A V1 , A W1 At least one of them will be a value other than "0".

[0044] However, if the calculation result of the original abnormality calculation unit 516 is valid, the current detection value I input to the original abnormality calculation unit 516 U ,I V ,I W Rather, the current estimate I input to the abnormality calculation unit 518-1U1 ,I V1 ,I W1 The true value of current I UT ,I VT ,I WT Since it is considered to be approaching this value, the above equation (35) holds true.

[0045] (Abnormality correction unit 519-1) The abnormality correction unit 519-1 calculates the original abnormality value A U0 ,A V0 ,A W0 And, the estimated value of the anomaly A U1 ,A V1 ,A W1 Using and, for example, based on the following equations (36) to (38), predict relative anomaly A U1C ,A V1C ,A W1C Calculate the (first predicted anomaly). A U1C =A U0 +A U1 …(36) A V1C =A V0 +A V1 …(37) A W1C =A W0 +A W1 …(38)

[0046] In the above equations (36) to (38), the original abnormality calculation value A U0 ,A V0 ,A W0 And, the estimated value of the anomaly A U1 ,A V1 ,A W1 Although we simply added the two, we could also perform a sum-of-products operation by multiplying both by a weighting constant and then adding the results.

[0047] (Abnormality judgment unit 514) The anomaly detection unit 514 predicts relative anomaly A U1C ,A V1C ,A W1CBased on this, the system determines whether or not there is an abnormality in the current detectors 24, 25, and 26, and displays abnormality information identifying the current detector that was determined to have an abnormality on the inverter-side display unit 52b. Furthermore, the abnormality detection unit 514 predicts the period until a predetermined abnormal state occurs in the current detectors 24, 25, and 26 based on the history of the degree of abnormality of the current detectors 24, 25, and 26 over multiple occasions, and displays the predicted period on the inverter-side display unit 52b.

[0048] For example, the predicted relative anomaly A is considered to be when current detectors 24, 25, and 26 are considered to be functioning normally. U1C ,A V1C ,A W1C Assume that the tolerance value was Ath (not shown). The anomaly determination unit 514 determines each predicted relative anomaly A based on the past trend of predicted relative anomalies. U1C ,A V1C ,A W1C The inverter-side display unit 52b displays the period until the value is predicted to exceed the allowable value Ath. Further details of the abnormality detection unit 514 will be described later.

[0049] (Details of the inverter-side abnormality detection unit 51b) <<Original abnormality degree calculation unit 516>> The details of each part of the inverter-side abnormality detection unit 51b described above will be explained below. Figure 6 is a block diagram showing the details of the original abnormality calculation unit 516. The original anomaly calculation unit 516 includes an anomaly calculation processing unit 511. However, in the illustrated example, the original anomaly calculation unit 516 is equivalent to the anomaly calculation processing unit 511.

[0050] The abnormality calculation processing unit 511 calculates the input current value I UX ,I VX ,I WX Based on this, the anomaly calculation result A UX ,A VX ,A WX It outputs the following. The original abnormality calculation unit 516 then calculates the current detection value I U ,I V ,I W As such, the input current value IUX ,I VX ,I WX Apply this and calculate the anomaly score A UX ,A VX ,A WX Original abnormality calculation value A U0 ,A V0 ,A W0 This is what will be output.

[0051] In Figure 6, the abnormality calculation processing unit 511, or rather the original abnormality calculation unit 516, comprises an adder 5111 (first adder), multipliers 5112U, 5112V, 5112W (first multiplier), filters 5113U, 5113V, 5113W (first filter), multipliers 5114U, 5114V, 5114W (third multiplier), adder 5115 (third adder), filter 5116 (third filter), multipliers 5114CU, 5114CV, 5114CW (second multiplier), adder 5115C (second adder), filter 5116C (second filter), and an arithmetic unit 5117.

[0052] Current detection value I detected by the U-phase current detector 24 (see Figure 1) U The input current value I of the U phase UX The current detected by the V-phase current detector 25 is supplied as follows: adder 5111 and multipliers 5112U, 5114U, 5114CV, 5114CW. V The input current value I of the V phase VX The current is supplied to the adder 5111 and the multipliers 5112V, 5114V, 5114CW, and 5114CU. The current detection value I detected by the W-phase current detector 26 W The input current value I for the W phase is WX It is supplied to adder 5111 and multipliers 5112W, 5114W, 5114CU, and 5114CV.

[0053] The adder 5111 receives an input current value I UX ,I VX ,I WX Enter the sum of the sum I I0 (=I UX +I VX +IWX Output as ). The calculated input sum I I0 These are input to the multipliers 5112U, 5112V, and 5112W, respectively. Incidentally, it is desirable for the original abnormality calculation unit 516 to employ a judgment method that utilizes Kirchhoff's current law.

[0054] In other words, according to Kirchhoff's current law, the true value of the current I UT ,I VT ,I WT Since the sum is 0, the input sum value I I0 If the value is "0", then current detectors 24, 25, and 26 (see Figure 2) can be presumed to be functioning normally. On the other hand, the total input value I I0 If the value is not "0", it can be estimated that one of the current detectors 24, 25, or 26 is malfunctioning. Furthermore, a method that can quantitatively calculate the relative degree of malfunction of the current detectors is desirable.

[0055] The multiplier 5112U uses the input current value I for the U phase. UX and the input sum value I I0 Product D U The multiplier 5112V calculates the input current value I of the V phase. VX and the input sum value I I0 Product D V The multiplier 5112W calculates the input current value I for the W phase. WX and the input sum value I I0 Product D W Calculate the product D for filters 5113U, 5113V, and 5113W, respectively. U ,D V ,D W By performing a process to reduce or remove the AC component from (the first product), the DC component F is determined for the calculation unit 5117. U ,F V ,F W The (first filter result) is output. Filters 5113U, 5113V, and 5113W are filters or low-pass filters that output the average value for an input within a given time range. Filters 5113U, 5113V, and 5113W reduce or remove the AC component contained in the input signal, but below it will simply be described as "removing".

[0056] The multipliers 5114U, 5114V, and 5114W are each based on the input current value I UX ,I VX ,I WX I is the square of UX 2 ,I VX 2 ,I WX 2 It outputs the following. Adder 5115 outputs these squared values ​​I UX 2 ,I VX 2 ,I WX 2 Total value SH I (The third summation value) is output, and the filter 5116 outputs the summation value SH I The result obtained by removing the AC component is the DC component H I Output this as (the third filter result).

[0057] The multipliers 5114CU, 5114CV, and 5114CW are used with an input current value I UX ,I VX ,I WX Based on this, the multiplication result I VX I WX ,I WX I UX ,I UX I VX It outputs the following. The adder 5115C outputs these squared values ​​I UX 2 ,I VX 2 ,I WX 2 Total value SK I The filter 5116C outputs (the second summation value) and filters the summation value to remove or reduce high-frequency components, and the result is the DC component K I Output this as (second filter result).

[0058] The calculation unit 5117 receives the input DC component F U ,F V ,F W ,H I ,K I Based on this, the anomaly calculation result A UX ,AVX ,A WX The result of the abnormality calculation A is calculated below. UX ,A VX ,A WX The method for calculating this will be described in detail.

[0059] True values ​​of current I in U-phase, V-phase, and W-phase UT ,I VT ,I WT For example, if the waveform of the true current is a sine wave and the amplitude of the true current is I for all three phases. IA Therefore, if the phase difference of the sinusoidal waveforms of the true current values ​​of each phase is 2π / 3 (radians), then it can be expressed by the following equations (39) to (41). I UT =I IA ×cos(ωt) …(39) I VT =I IA ×cos(ωt-2π / 3) …(40) I WT =I IA ×cos(ωt-4π / 3) …(41) However, I IA As mentioned earlier, ω is the current amplitude, t is time, and ω = 2πf is the angular frequency (f is the frequency).

[0060] Furthermore, from equations (21) to (26) and equations (39) to (41), the current detection values ​​I for the U phase, V phase, and W phase are obtained. U ,I V ,I W This is expressed by equations (42) to (44). I U =(1+A UR ) × B I ×cos(ωt) …(42) I V =(1+A VR ) × B I ×cos(ωt-2π / 3) …(43) I W =(1+A WR ) × B I ×cos(ωt-4π / 3) …(44)

[0061] In the case where the current shown in equations (39) to (41) above is flowing, the total input value I in the original abnormality calculation unit 516 I0 , product D U ,D V ,D W , DC component F U ,F V ,F W , DC component H I , DC component K I Explain the significance of these terms.

[0062] The sum of input values ​​I output from adder 5111 in Figure 6. I0 This can be expressed by the following equation (45). I I0 =I UX +I VX +I WX =I U +I V +I W =B I × (A UR ×cos(ωt)+A VR ×cos(ωt-2π / 3) +A WR ×cos(ωt-4π / 3)) …(45)

[0063] Furthermore, the product D is the output of the multipliers 5112U, 5112V, and 5112W. U ,D V ,D W This is expressed by the following equations (46) to (48). In equations (46) to (48), the symbol √(X) represents X. 1 / 2 This represents the same, and so on. D U =(I UX +I VX +I WX ) × I UX =(I U +I V +I W ) × I U = 1 / 2 × B I 2 A UR ×(1+AUR )×(1+cos(2ωt)) -1 / 4×B I 2 A VR ×(1+A UR )×(1+cos(2ωt)-√(3)×sin(2ωt)) -1 / 4×B I 2 A WR ×(1+A UR )×(1+cos(2ωt)+√(3)×sin(2ωt)) …(46)

[0064] D V =(I UX +I VX +I WX )×I VX =(I U +I V +I W )×I V =-1 / 4×B I 2 A UR ×(1+A VR )×(1+cos(2ωt)-√(3)×sin(2ωt)) +1 / 2×B I 2 A VR ×(1+A VR )×(1+cos(2ωt-4π / 3)) -1 / 4×B I 2 A WR ×(1+A VR )×(1-2×cos(2ωt)) …(47)

[0065] D W =(I UX +I VX +I WX )×I WX =(I U +I V +I W )×I W =-1 / 4×B I 2 AUR ×(1+A WR )×(1+cos(2ωt)+√(3)×sin(2ωt)) -1 / 4 × B I 2 A VR ×(1+A WR ) × (1 - 2 × cos(2ωt)) +1 / 2 × B I 2 A WR ×(1+A WR ) × (1 + cos(2ωt - 8π / 3)) …(48)

[0066] DC component F output by filters 5113U, 5113V, and 5113W U ,F V ,F W is the product D U ,D V ,D W This is obtained by removing the periodic change component due to trigonometric functions, and is expressed by the following equations (49) to (51). F U = 1 / 4 × B I 2 × (2A UR -A VR -A WR ) × (1 + A UR ) …(49) F V = 1 / 4 × B I 2 × (2A VR -A WR -A UR ) × (1 + A VR ) …(50) F W = 1 / 4 × B I 2 × (2A WR -A UR -A VR ) × (1 + A WR ) …(51)

[0067] Furthermore, substituting the aforementioned equation (27) into equations (49) to (51) and rearranging, we get the DC component F. U ,F V ,F WThis can be expressed by equations (52) to (54). F U = 3 / 4 × B I 2 A UR ×(1+A UR ) …(52) F V = 3 / 4 × B I 2 A VR ×(1+A VR ) …(53) F W = 3 / 4 × B I 2 A WR ×(1+A WR ) …(54)

[0068] Also, the sum SH output by adder 5115 I This is as shown in equation (55). SH I =I UX 2 +I VX 2 +I WX 2 =I U 2 +I V 2 +I W 2 =B I 2 ×(1+A UR ) 2 ×(1+cos(2ωt)) / 2 +B I 2 ×(1+A VR ) 2 ×(1+cos(2ωt-4π / 3)) / 2 +B I 2 ×(1+A WR ) 2 ×(1+cos(2ωt-8π / 3)) / 2 …(55)

[0069] DC component H output by filter 5116 IThe total value is SH I This is obtained by removing the periodic change component due to trigonometric functions, and is expressed by the following equation (56). Note that the aforementioned equation (27) was used in the calculation process. H I = 3 / 2 × B I 2 +1 / 2 × B I 2 × (A UR 2 +A VR 2 +A WR 2 ) …(56)

[0070] The sum SK output by adder 5115C I This can be expressed by the following equation (57). SK I =I UX I VX +I VX I WX +I WX I UX =I U I V +I V I W +I W I U = -1 / 4 × B I 2 ×(1+A UR ) × (1 + A VR )×(1+cos(2ωt)-√(3)×sin(2ωt)) -1 / 4 × B I 2 ×(1+A VR ) × (1 + A WR ) × (1 + 2 × cos(2ωt)) -1 / 4 × B I 2 ×(1+A WR ) × (1 + A UR )×(1+cos(2ωt)+√(3)×sin(2ωt)) …(57)

[0071] Filter 5116C receives the total value SK I For each of these, a filtering process is performed to remove the AC component contained in each, and the total value SK is obtained. I The DC component of is K I Outputs. The total value SK expressed by the above formula (57) I When filtering is applied to remove the AC component, that is, when the periodic change of the trigonometric function is removed, the DC component K output by filter 5116C is I This is expressed by equation (58). Note that equation (27) mentioned above was used in the calculation process. K I = -3 / 4 × B I 2 -1 / 4 × B I 2 × (A UR A VR +A VR A WR +A WR A UR ) …(58)

[0072] The calculation unit 5117 processes the DC component F output from filters 5113U, 5113V, 5113W, 5116, and 5116C. U ,F V ,F W ,H I ,K I Based on this, the anomaly calculation result A UX ,A VX ,A WX (In the original abnormality calculation unit 516, the original abnormality calculation value A U0 ,A V0 ,A W0 The result of the abnormality calculation A is calculated. UX ,A VX ,A WX This is calculated using equations (61), (65) to (67), and (69) to (71), which will be described later.

[0073] As mentioned above H I Equations (56) and K relating to I By rearranging each of equations (58) related to the above using equation (27), we obtain the following equations (59) and (60). 2×H I =3 × B I 2 +2×B I 2 × (A VR 2 +A WR 2 +A VR A WR ) …(59) 8×K I = -6 × B I 2 +2×B I 2 × (A VR 2 +A WR 2 +A VR A WR ) …(60)

[0074] From equations (59) and (60), relative anomaly A UR ,A VR ,A WR Eliminating this leads to equation (61). B I 2 =(2H I -8K I ) / 9 …(61) Rearranging equations (52) to (54) above, the relative anomaly A is as shown in equations (62) to (64). UR ,A VR ,A WR A quadratic equation is obtained for each of these. 3B I 2 A UR 2 +3B I 2 A UR -4F U =0 …(62) 3B I 2 A VR 2 +3B I 2 A VR -4F V=0 …(63) 3B I 2 A WR 2 +3B I 2 A WR -4F W =0 …(64)

[0075] The relative anomaly score A was obtained by applying the quadratic formula to each of equations (62) to (64). UR ,A VR ,A WR The solution is shown below in the abnormality calculation result A. U0C ,A V0C ,A W0C This is called the abnormality calculation result A. U0C ,A V0C ,A W0C This is given by equations (65) to (67). A U0C =(-3B I 2 +√(9B I 4 +48B I 2 F U )) / (6B I 2 ) …(65) A V0C =(-3B I 2 +√(9B I 4 +48B I 2 F V )) / (6B I 2 ) …(66) A W0C =(-3B I 2 +√(9B I 4 +48B I 2 F W )) / (6B I 2 ) …(67)

[0076] As shown in equations (39) to (41) above, the true value of the current IUT ,I VT ,I WT This assumes that the current is sinusoidal. Therefore, the abnormality calculation result A calculated by equations (65) to (67) U0C ,A V0C ,A W0C This represents the degree of abnormality in the U, V, and W phases under an ideal state without current pulsation.

[0077] Note that while the sign immediately preceding the square root in the quadratic formula is ±, in equations (65) to (67) it is +. In this case, the abnormality calculation result A U0C If we assume that is "0", then the right-hand side of equation (65) is "(-3B I 2 +√(9B I 4 +48B I 2 F U Since )) becomes "0", this is the DC component F U This means that it is "0". On the other hand, if the sign immediately before the square root is "-", then the right side of equation (65) is "(-3B I 2 -√(9B I 4 +48B I 2 F U The result of )) does not become "0". Therefore, the sign immediately preceding the square root must be "+".

[0078] Abnormality calculation result A U0C ,A V0C ,A W0C This represents the degree of abnormality in the U, V, and W phases in an ideal state without current pulsation. Therefore, if the current waveform does not contain a pulsating component, the abnormality calculation result A U0C ,A V0C ,A W0C The sum of these is the relative anomaly A UR ,A VR ,A WR The result is "0", similar to the case above. In other words, if the current waveform does not contain a pulsating component, the result is "A U0C +A V0C +A W0Cbecomes "= 0". On the other hand, when the current waveform contains a pulsation component, "A U0C + A V0C + A W0C > 0".

[0079] Therefore, the abnormality calculation result A UX , A VX , A WX is introduced. The abnormality calculation result A UX , A VX , A WX , that is, the abnormality calculation result A U0C , A V0C , A W0C is defined as a quantity set so that the following equations (68) to (71) hold. A UX + A VX + A WX = 0 …(68) A UX = A U0C - (A U0C + A V0C + A W0C ) / 3 …(69) A VX = A V0C - (A U0C + A V0C + A W0C ) / 3 …(70) A WX = A W0C - (A U0C + A V0C + A W0C ) / 3 …(71)

[0080] The second term on the right side of each of the equations (69) to (71) can be considered as a correction term for the abnormality calculation result A U0C , A V0C , A W0C to satisfy the equation (68). Even when the current waveform contains a pulsation component and "A U0C + A V0C + A W0C > 0", for the abnormality calculation result A UX , A VX , A WX , it is "A UX + A VX + AWX The statement "=0" holds true. And, as described above, in the original abnormality calculation unit 516, abnormality calculation result A UX ,A VX ,A WX The original abnormality calculation value A U0 ,A V0 ,A W0 Output as follows.

[0081] <<Computer>> Figure 7 is a block diagram of the computer 980. Both the control device 41 and the anomaly detection unit 51 shown in Figure 1 are equipped with one or more computers 980 as shown in Figure 7. In Figure 7, the computer 980 comprises a CPU 981, a storage unit 982, a communication interface 983, an input / output interface 984, and a media interface 985. Here, the storage unit 982 comprises a RAM 982a, a ROM 982b, and an HDD 982c. The communication interface 983 is connected to the communication circuit 986. The input / output interface 984 is connected to the input / output device 987. The media interface 985 reads and writes data to and from the recording medium 988.

[0082] ROM982b stores the IPL (Initial Program Loader) and other programs executed by the CPU. HDD982c stores control programs and various data. CPU981 implements various functions by executing the control programs and other data read from HDD982c into RAM982a. The internal structure of the inverter-side abnormality detection unit 51b, etc., shown earlier in Figures 5 and 6, represents the functions implemented by the control programs and other data as blocks.

[0083] <<Abnormality calculation unit 518-1>> The internal configuration of the abnormality calculation unit 518-1 shown in Figure 5 is the same as that of the original abnormality calculation unit 516 (see Figure 6). However, the current detection value I input to the original abnormality calculation unit 516 is different. U ,I V ,I W Instead, the abnormality calculation unit 518-1 receives the current estimate IU1 ,I V1 ,I W1 However, the input current value I UX ,I VX ,I WX These are input as follows. Furthermore, the abnormality calculation unit 518-1 calculates these estimated current values ​​I U1 ,I V1 ,I W1 Based on this, the anomaly calculation result A is calculated. UX ,A VX ,A WX Anomaly degree estimate A U1 ,A V1 ,A W1 Output as follows.

[0084] <Operation of the First Embodiment> Next, the operation of this embodiment will be described. Figure 8 is a flowchart showing an example of the abnormality detection process in the inverter-side abnormality detection unit 51b (see Figure 5). In Figure 8, when the process proceeds to step S101, the anomaly correction unit 519-1 predicts the relative anomaly A based on the above-described equations (36) to (38). U1C ,A V1C ,A W1C Calculate.

[0085] Next, when the process proceeds to step S102, the anomaly determination unit 514 determines whether the following equation (72) is true. Here, MAX(a,b,c) represents the largest value among a,b,c. That is, in step S102, the anomaly determination unit 514 determines whether the predicted relative anomaly degree A U1C ,A V1C ,A W1C It is determined whether the largest of the absolute values ​​exceeds a predetermined value J1 (abnormality detection threshold). MAX(|A U1C |,|A V1C |,|A W1C |) > J1 …(72)

[0086] If "No" is determined in step S102, the process proceeds to step S111. Here, the abnormality detection unit 514 determines that all current detectors 24, 25, and 26 are normal, and the processing of this routine ends.

[0087] On the other hand, if "Yes" is determined in step S102, the process proceeds to step S103, and the abnormality determination unit 514 determines whether the following equation (73) is true. Here, [MAX] is "MAX(|A U1C |,|A V1C |,|A W1C |) represents "MIN(|A U1C |,|A V1C |,|A W1C This represents |). Also, MIN(a,b,c) represents the smallest value among a,b,c. The predetermined value J2 is, for example, "50%". Note that equation (73) is an equation for determining whether multiple of the current detectors 24, 25, 26 (see Figure 1) are abnormal. ([MAX]-2×[MIN]) / [MAX] > J2 …(73)

[0088] If "Yes" is determined in step S103, the process proceeds to step S104. Here, the abnormality detection unit 514 displays a message on the inverter-side display unit 52b (see Figure 2) indicating that multiple current detectors are abnormal, for example, "Multiple current detector abnormalities." Next, when the process proceeds to step S112, the abnormality detection unit 514 displays abnormality check information on the inverter-side display unit 52b, and the processing of this routine ends. The abnormality check information is, for example, a message such as "Please inspect and replace the abnormal parts."

[0089] The predetermined values ​​J1 and J2 mentioned above may be either constant or variable. For example, in principle, the current detection value I U ,I V ,I WWhen all are near "0", the degree of abnormality of the current detectors 24, 25, and 26 becomes difficult to see, making abnormal diagnosis difficult. Thus, in order not to cause misjudgment when the current value is small, predetermined values J1 and J2 may be set according to the magnitudes of the current detection values I U , I V , I W .

[0090] By the way, assuming that the average value of the true relative abnormality degrees A UR , A VR , A WR for the plurality of current detectors 24, 25, and 26, that is, "(A UR + A VR + A WR ) / 3" is "0", from expressions (69) to (71), "A U0 = A U0C , A V0 = A V0C , A W0 = A W0C " holds. That is, the original abnormality degree calculation values A U0 , A V0 , A W0 are equal to the abnormality degree calculation results A U0C , A V0C , A W0C .

[0091] When it is determined as "No" in the above step S103, the process proceeds to step S105. Here, the abnormality determination unit 514 determines whether the following expression (74) holds. MAX(|A U1C |, |A V1C |, |A W1C |) = |A U1C | …(74)

[0092] If "Yes" is determined here, the process proceeds to step S106, where the abnormality determination unit 514 determines that the U-phase current detector 24 is abnormal and displays information to that effect, such as the message "U-phase current detector abnormality," on the inverter-side display unit 52b. Next, in step S112, the abnormality determination unit 514 displays abnormality check information on the inverter-side display unit 52b, and the processing of this routine ends.

[0093] By the way, the calculated original abnormality value A of the V-phase current detector 25 and the W-phase current detector 26. V0 ,A W0 Assuming both are "0", the calculated original abnormality value A of the U-phase current detector 24 is U0 This can be calculated using the following formula (75). A U0 =(3×A U0C ) / (2-A U0C ) …(75)

[0094] Equation (75) can be estimated, for example, as follows: From equations (21) and (24) mentioned above, we obtain equation (76). G U =G U0 ×(G U +G V +G W ) / 3 …(76)

[0095] Equation (76) is for absolute anomaly A U ,A V ,A W and relative anomaly A UR Expressed using this, we get equation (77). 1+A U =(1+A UR )×(A U +A V +A W +3) / 3 …(77)

[0096] A V =A W Assuming that = 0, we obtain equation (78). 1+A U =(1+A UR )×(A U +3) / 3 A U =(3×A UR ) / (2-A UR ) …(78) The relative anomaly A on the right-hand side of equation (78) UR Instead, abnormality calculation result A U0C Those using the absolute abnormality grade A U If it is an estimated value, then the above equation (75) is obtained.

[0097] The above equation (73) has three elements (|A U1C |,|A V1C |,|A W1C This formula determines whether or not a given element can be classified into two elements with high similarity and one element with low similarity to those two elements. Formula (73) is just one example of a determination method; instead of using formula (73), a similar determination may be made using, for example, any clustering analysis method.

[0098] If the result in step S105 described above is "No", the process proceeds to step S107. Here, the abnormality determination unit 514 determines whether the following equation (79) is true. MAX(|A U1C |,|A V1C |,|A W1C |)=|A V1C | …(79)

[0099] If "Yes" is determined here, the process proceeds to step S108, where the abnormality determination unit 514 determines that the V-phase current detector 25 is abnormal and displays information to that effect, such as the message "V-phase current detector abnormality," on the inverter-side display unit 52b. Next, in step S112, the abnormality determination unit 514 displays abnormality check information on the inverter-side display unit 52b, and the processing of this routine ends.

[0100] By the way, the calculated original abnormality value A of the U-phase current detector 24 and the W-phase current detector 26. U0 ,A W0 Assuming both are "0", the calculated original abnormality value A of the V-phase current detector 25 is V0 This can be calculated using the following equation (80). Equation (80) is obtained in the same way as equation (75) above. A V0 =(3×A V0C ) / (2-A V0C ) …(80)

[0101] If the result in step S107 described above is "No", the process proceeds to step S109. Here, the abnormality determination unit 514 determines whether the following equation (81) is true. MAX(|A U1C |,|A V1C |,|A W1C |)=|A W1C | …(81)

[0102] If "Yes" is determined here, the process proceeds to step S110, where the abnormality determination unit 514 determines that the W-phase current detector 26 is abnormal and displays information to that effect, such as the message "W-phase current detector abnormality," on the inverter-side display unit 52b. Next, in step S112, the abnormality determination unit 514 displays abnormality check information on the inverter-side display unit 52b, and the processing of this routine ends.

[0103] By the way, the calculated original abnormality value A of the U-phase current detector 24 and the V-phase current detector 25. U0 ,A V0 Assuming both are "0", the calculated original abnormality value A of the W-phase current detector 26 is W0 This can be calculated using the following equation (82). Equation (82) is obtained in the same way as equation (75) above. A W0 =(3×A W0C ) / (2-A W0C ) …(82)

[0104] If the result in step S109 is "No", the process proceeds to step S111. As described above, in step S111, the abnormality determination unit 514 determines that all current detectors 24, 25, and 26 are normal, and the processing of this routine ends. In this case, it is not necessarily required to display on the inverter-side display unit 52b that all current detectors 24, 25, and 26 are normal, but it is of course optional to do so.

[0105] <Simulation results of the first embodiment> Next, the simulation results of the first embodiment will be described. Figure 9 is a circuit diagram of load device 2, etc., applied to the simulation. In Figure 9, the load device 2 comprises resistors 6U, 6V, and 6W, and coils 7U, 7V, and 7W. One end of each resistor 6U, 6V, and 6W is connected to AC wiring 21, 22, and 23, and the other end of each resistor 6U, 6V, and 6W is connected to one end of each coil 7U, 7V, and 7W. The other end of each coil 7U, 7V, and 7W is connected to the neutral point 2N.

[0106] The resistance values ​​of resistors 6U, 6V, and 6W are (1-β)R, R, and R, respectively, and the inductances of coils 7U, 7V, and 7W are (1-β)L, L, and L, respectively. β is a predetermined unbalance constant. If the unbalance constant β is "0", the load device 2 becomes a three-phase balanced load, and the closer the unbalance constant β approaches "1", the greater the degree of three-phase unbalance. The configuration of the power converter 100 is the same as that shown in Figure 1.

[0107] Figure 10 shows an example of the simulation results. In Figure 10, the unbalance constant β is set to "0.1", the U-phase and W-phase current detectors 24 and 26 are assumed to be normal (gain 100%), and the V-phase current detector 25 is assumed to have a gain anomaly (gain 96.1%). That is, the absolute anomaly degree mentioned above is A U =0%, A V = -5.9%, A W= 0%. Converting these absolute anomalies to relative anomalies based on equations (5) to (10), (20), and (24) to (26) gives A UR =+2%, A VR =-4%, A WR = +2%

[0108] The upper graph in Figure 10 shows the current detection value I U ,I V ,I W And the sum of these is the input sum value I I0 This is shown. Also, the graph in the middle shows the total input value I in the original abnormality calculation unit 516. I0 And the total input value I in the abnormality calculation unit 518-1 I0 This indicates the following: The total input value I in the abnormality calculation unit 518-1. I0 This is the estimated current value I U1 ,I V1 ,I W1 It is equal to the sum of.

[0109] Furthermore, the graph below shows the calculated value of the original abnormality A. U0 ,A V0 ,A W0 And, predicted relative anomaly A U1C ,A V1C ,A W1C This shows the following. In the upper and middle graphs, the horizontal axis represents time, and the vertical axis represents the instantaneous current value (amperes). In the lower graph, the vertical axis represents the calculated result (%) of various anomalies.

[0110] If all current detectors 24, 25, and 26 are functioning correctly, then according to Kirchhoff's current law, the total input value I in the original abnormality calculation unit 516 is calculated. I0 This should always be "0". However, as mentioned above, a gain anomaly occurs in the V-phase current detector 25, so the input sum value I is as shown in the upper and middle graphs of Figure 10. I0 It's not always "0".

[0111] As described above, the total input value I in the original abnormality calculation unit 516 I0 This is simply the current detection value I U ,I V ,IW This is calculated from the input sum value I I0 This is the estimated current value I that reflects the diagnostic results from the original abnormality calculation unit 516. U1 ,I V1 ,I W1 This value is based on the following. And, as shown in the graph below, the original anomaly calculation value A U0 ,A V0 ,A W0 Rather than, the predicted relative anomaly A U1C ,A V1C ,A W1C This is the true relative anomaly A under the simulation conditions. UR ,A VR ,A WR It can be seen that the error with (=+2%, -4%, +2%) has decreased.

[0112] Figure 11 shows another example of the simulation results. In Figure 11, the unequilibrium constant β is set to "0.5", and the other conditions are the same as in Figure 10. The meanings of the upper, middle, and lower graphs in Figure 11 are also the same as in Figure 10. As shown in the lower graph of Figure 11, even when the unequilibrium constant β is set to "0.5", the original anomaly calculation value A U0 ,A V0 ,A W0 Rather than, the predicted relative anomaly A U1C ,A V1C ,A W1C This is the true relative anomaly A under the simulation conditions. UR ,A VR ,A WR It can be seen that the error with (=+2%, -4%, +2%) has decreased.

[0113] Even if a three-phase imbalance occurs in load device 2, I is the same as when there is three-phase balance. U ,I V ,I W ,I I0 The amount of phase change is relatively small. Therefore, as shown in Figures 10 and 11, the original anomaly calculation value A by the original anomaly calculation unit 516 is U0 ,A V0 ,A W0The true relative anomaly A under the simulation conditions can be determined solely by this. UR ,A VR ,A WR The error can be made relatively small compared to (=+2%, -4%, +2%).

[0114] Furthermore, as shown in Figure 5, by providing a current estimation unit 517-1, an anomaly calculation unit 518-1, and an anomaly correction unit 519-1 in addition to the original anomaly calculation unit 516, the true relative anomaly A UR ,A VR ,A WR A more accurate anomaly estimate A U1 ,A V1 ,A W1 You can obtain this.

[0115] [Second Embodiment] Next, a second embodiment will be described. In the following description, parts corresponding to the parts of the first embodiment described above will be denoted by the same reference numerals, and their descriptions may be omitted. The overall configuration of the second embodiment is the same as that of the first embodiment (see Figures 1 to 4). However, in this embodiment, instead of the inverter-side abnormality determination unit 51b of the first embodiment (see Figure 5), an inverter-side abnormality determination unit 56, for example, shown in Figure 12, is applied.

[0116] Figure 12 is a block diagram of the inverter-side abnormality detection unit 56 in the second embodiment. The inverter-side abnormality determination unit 56, like the inverter-side abnormality determination unit 51b of the first embodiment (see Figure 5), includes a base abnormality calculation unit 516, a current estimation unit 517-1, an abnormality calculation unit 518-1, and an abnormality correction unit 519-1.

[0117] Furthermore, the inverter-side abnormality determination unit 56 includes, in addition to the above-described configuration, a current estimation unit 517-2, an abnormality calculation unit 518-2, and an abnormality correction unit 519-2. The current estimation unit 517-2 and the abnormality calculation unit 518-2 have the same configuration as the current estimation unit 517-1 and the abnormality calculation unit 518-1, respectively.

[0118] (Current estimation section 517-2) However, the current estimation unit 517-2 receives the predicted relative anomaly A output by the anomaly correction unit 519-1. U1C ,A V1C ,A W1C This is input. As a result, the current estimation unit 517-2 calculates the current detection value I from the current detectors 24, 25, and 26. U ,I V ,I W And, predicted relative anomaly A U1C ,A V1C ,A W1C Based on this, the true value of the current I UT ,I VT ,I WT The current estimate I is calculated by estimating the current and using the result as shown in equations (83) to (85) below. U2 ,I V2 ,I W2 Output as follows. I U2 =I U / (1+A U1C ) …(83) I V2 =I V / (1+A V1C ) …(84) I W2 =I W / (1+A W1C ) …(85)

[0119] (Abnormality calculation unit 518-2) Furthermore, the abnormality calculation unit 518-2 calculates the input current value I in the abnormality calculation processing unit 511 (see Figure 6). UX ,I VX ,I WX Current estimate I U2 ,I V2 ,I W2 Applying this, the calculation result is the anomaly calculation result A. UX ,A VX ,A WX Anomaly degree estimate A U2 ,A V2 ,A W2 Output as follows.

[0120] (Abnormality correction unit 519-2) Furthermore, the abnormality correction unit 519-2 calculates the original abnormality value A U0 ,A V0 ,A W0 And, the estimated value of the anomaly A U1 ,A V1 ,A W1 And, the estimated value of the anomaly A U2 ,A V2 ,A W2 For example, based on the following equations (86) to (88), the predicted relative anomaly A U2C ,A V2C ,A W2C Perform the calculation. A U2C =A U0 +A U1 +A U2 …(86) A V2C =A V0 +A V1 +A V2 …(87) A W2C =A W0 +A W1 +A W2 …(88)

[0121] (Abnormality judgment unit 514) The abnormality determination unit 514 in the inverter-side abnormality determination unit 56 predicts relative abnormality degree A U1C ,A V1C ,A W1C Instead, predict relative anomaly A U2C ,A V2C ,A W2C This is applied to perform the same processing as the abnormality determination unit 514 in the first embodiment.

[0122] [Third Embodiment] Next, a third embodiment will be described. In the following description, parts corresponding to the parts of the other embodiments described above will be denoted by the same reference numerals, and their descriptions may be omitted. The overall configuration of the third embodiment is the same as that of the first embodiment (see Figures 1 to 4). However, in this embodiment, instead of the inverter-side abnormality determination unit 51b of the first embodiment (see Figure 5), an inverter-side abnormality determination unit 58, for example, shown in Figure 13, is used.

[0123] Figure 13 is a block diagram of the inverter-side abnormality detection unit 58 in the third embodiment. The inverter-side abnormality determination unit 58, like the inverter-side abnormality determination unit 56 of the second embodiment (see Figure 12), includes an original abnormality calculation unit 516, current estimation units 517-1 and 517-2, abnormality calculation units 518-1 and 518-2, abnormality correction units 519-1 and 519-2, and an abnormality determination unit 514.

[0124] Furthermore, the inverter-side abnormality determination unit 58 includes, in addition to the above-described configuration, a current estimation unit 517-3, an abnormality calculation unit 518-3, and an abnormality correction unit 519-3. The current estimation unit 517-3 and the abnormality calculation unit 518-3 have the same configuration as the current estimation unit 517-1 and the abnormality calculation unit 518-1, respectively.

[0125] (Current estimation section 517-3) However, the current estimation unit 517-3 receives the predicted relative anomaly A output by the anomaly correction unit 519-2. U2C ,A V2C ,A W2C This is input. As a result, the current estimation unit 517-3 calculates the detected values ​​I from the current detectors 24, 25, and 26. U , I V , I W And, predicted relative anomaly A U2C ,A V2C ,A W2C Based on this, the true value of the current I UT ,I VT ,I WT The current estimate I is calculated by estimating the current and using the result as shown in equations (89) to (91), for example. U3 ,I V3 ,I W3 Output as follows. I U3 =I U / (1+AU2C ) …(89) I V3 =I V / (1+A V2C ) …(90) I W3 =I W / (1+A W2C ) …(91)

[0126] (Abnormality calculation unit 518-3) Furthermore, the abnormality calculation unit 518-3 calculates the input current value I in the abnormality calculation processing unit 511 (see Figure 6). UX ,I VX ,I WX Current estimate I U3 ,I V3 ,I W3 Applying this, the calculation result is the anomaly calculation result A. UX ,A VX ,A WX Anomaly degree estimate A U3 ,A V3 ,A W3 Output as follows.

[0127] (Abnormality correction unit 519-3) Furthermore, the abnormality correction unit 519-3 calculates the original abnormality value A U0 ,A V0 ,A W0 And, the estimated value of the anomaly A U1 ,A V1 ,A W1 And, the estimated value of the anomaly A U2 ,A V2 ,A W2 And, the estimated value of the anomaly A U3 ,A V3 ,A W3 For example, based on the following equations (92) to (94), the predicted relative anomaly A U3C ,A V3C ,A W3C Perform the calculation. A U3C =A U0 +A U1 +A U2 +A U3 …(92) A V3C =A V0 +AV1 +A V2 +A V3 …(93) A W3C =A W0 +A W1 +A W2 +A W3 …(94)

[0128] <Configuration corresponding to an arbitrary number of additional processing stages N> In the example shown in Figure 13, three current estimation units 517-1 to 517-3, anomaly calculation units 518-1 to 518-3, and anomaly correction units 519-1 to 519-3 are provided. However, any natural number greater than or equal to "2" can be used as the "number of additional processing stages N", and N stages of current estimation units 517-1 to 517-N, anomaly calculation units 518-1 to 518-N, and anomaly correction units 519-1 to 519-N may be provided. That is, the inverter-side anomaly determination unit 58 includes, for a natural number K such that "2 ≤ K ≤ N", a current estimation unit 517-K (the Kth current estimation unit), an anomaly calculation unit 518-K (the Kth anomaly calculation unit), and an anomaly correction unit 519-K (the Kth anomaly correction unit), as described below.

[0129] (Current estimation section 517-K) The current estimation unit 517-K (for example, current estimation unit 517-3) reads the predicted relative anomaly A output by the anomaly correction unit 519-(K-1) (for example, anomaly correction unit 519-2). U(K-1)C ,A V(K-1)C ,A W(K-1)C (Same, predicted relative anomaly A) U2C ,A V2C ,A W2C The following is input: ) As a result, the current estimation unit 517-K calculates the detected values ​​I from the current detectors 24, 25, and 26. U , I V , I W And, predicted relative anomaly A U(K-1)C ,A V(K-1)C ,A W(K-1)C Based on this, the true value of the current I UT ,I VT ,I WT The current estimate I is calculated by estimating the current and using the result of that estimation as shown in equations (95) to (97) below. UK ,I VK ,IWK (Estimated current value for step K) (Estimated current value I shown in equations (89) to (91)) U3 ,I V3 ,I W3 Output as ). I UK =I U / (1+A U(K-1)C ) …(95) I VK =I V / (1+A V(K-1)C ) …(96) I WK =I W / (1+A W(K-1)C ) …(97)

[0130] (Abnormality calculation unit 518-K) Furthermore, the abnormality calculation unit 518-K (or abnormality calculation unit 518-3 if K=3) calculates the input current value I in the abnormality calculation processing unit 511 (see Figure 6). UX ,I VX ,I WX Current estimate I UK ,I VK ,I WK Applying this, the calculation result is the anomaly calculation result A. UX ,A VX ,A WX Anomaly degree estimate A UK ,A VK ,A WK (Estimated anomaly of the Kth order) (Same, estimated anomaly of the Ath U3 ,A V3 ,A W3 Output as ).

[0131] (Abnormality correction unit 519-K) Furthermore, the abnormality correction unit 519-K (or abnormality correction unit 519-3 if K=3) calculates the original abnormality value A U0 ,A V0 ,A W0 And, the estimated value of the anomaly A U1 ,A V1 ,A W1 ~A UK ,A VK ,A WKFor example, based on the following equations (98) to (100), the predicted relative anomaly A UKC ,A VKC ,A WKC (Predicted anomaly of the Kth order) (Same, predicted relative anomaly A) U3C ,A V3C ,A W3C ) is calculated. A UKC =A U0 +A U1 + … +A UK …(98) A VKC =A V0 +A V1 + … +A VK …(99) A WKC =A W0 +A W1 + … +A WK …(100)

[0132] In the above equations (98) to (100), the original abnormality calculation value A U0 ,A V0 ,A W0 And, the estimated value of the anomaly A U1 ,A V1 ,A W1 ~A UK ,A VK ,A WK Although the two were simply added together, a sum-of-products operation may also be performed by multiplying each element by a weighting constant and adding the results. The anomaly determination unit 514 then determines the predicted relative anomaly degree A U1C ,A V1C ,A W1C Instead, predict relative anomaly A UKC ,A VKC ,A WKC This is applied to perform the same processing as the abnormality determination unit 514 in the first embodiment.

[0133] <Simulation results of the third embodiment> Figure 14 shows an example of the simulation results in the third embodiment. The simulation conditions are the same as those shown in Figure 10. That is, the circuit shown in Figure 9 is applied to the simulation, and the absolute anomaly score is A.U =0%, A V = -5.9%, A W = 0%, which translates to A in relative anomaly. UR =+2%, A VR =-4%, A WR = +2%, and the unequilibrium constant β was set to "0.1". Furthermore, the meaning of the upper, middle, and lower graphs in Figure 14 is the same as that of Figure 10.

[0134] However, the graph in the middle of Figure 14 shows the total input value I in the original abnormality calculation unit 516 and the abnormality calculation unit 518-1. I0 In addition, the total input value I in the abnormality calculation unit 518-2 and abnormality calculation unit 518-3 I0 This was also included. Furthermore, the graph in the lower part of Figure 14 shows the calculated value of the original abnormality A. U0 ,A V0 ,A W0 And, predicted relative anomaly A U1C ,A V1C ,A W1C In addition, the predicted relative anomaly A U2C ,A V2C ,A W2C and predicted relative anomaly A U3C ,A V3C ,A W3C I also included that.

[0135] As shown in the middle graph of Figure 14, the total input value I in the abnormality calculation unit 518-2 and abnormality calculation unit 518-3 I0 This value is approximately "0" throughout the entire period shown in the figure. That is, the predicted relative anomaly A calculated by the anomaly correction unit 519-1 (see Figure 12) U1C ,A V1C ,A W1C Current estimate I calculated using U2 ,I V2 ,I W2 This is Kirchhoff's current law (I U2 +I V2 +I V2 It can be said that the degree of abnormality of current detectors 24, 25, and 26 is accurately represented to the extent that it satisfies (=0).

[0136] Also, as shown in the lower glass of Figure 14, A U1C ≒A U2C ≒A U3C , A V1C ≒A V2C ≒A V3C , A W1C ≒A W2C ≒A W3C Therefore, the original abnormality calculation value A by the original abnormality calculation unit 516 is as follows. U0 ,A V0 ,A W0 In comparison, it can be seen that the predicted relative anomaly score converges in the anomaly correction units 519-1 to 519-3.

[0137] Furthermore, as is clear from Figure 14 and the formulas described above, the total input value I in the abnormality calculation unit 518-K (or abnormality calculation unit 518-3 when K=3) I0 When it is approximately "0" (for example, current detection value I U ,I V ,I W If it is less than 1%, the predicted relative anomaly A in the anomaly correction unit 519-(K-1) and 519-K U(K-1)C ,A V(K-1)C ,A W(K-1)C and predicted relative anomaly A UKC ,A VKC ,A WKC (Same, predicted relative anomaly A) U3C ,A V3C ,A W3C and predicted relative anomaly A U2C ,A V2C ,A W2C When ) and become approximately equal, we can conclude that the calculation results have converged.

[0138] Figure 15 shows another example of the simulation results according to the third embodiment. In Figure 15, the unequilibrium constant β is set to "0.5", and the other conditions are the same as in Figure 14. The meaning of the upper, middle, and lower graphs in Figure 15 is also the same as in Figure 14. According to the middle graph in Figure 15, the total input value I increases with each stage, from the original abnormality calculation unit 516 to the abnormality calculation units 518-1 to 518-3. I0It is getting smaller. And the total input value I in the final stage abnormality calculation unit 518-3 I0 is almost "0" (for example, current detection value I U ,I V ,I W It is less than 1% of the total.

[0139] In other words, the predicted relative anomaly A calculated by the anomaly correction unit 519-3 U3C ,A V3C ,A W3C Using the current detection value I U ,I V ,I W Corrected current estimate (illustration omitted, but in equations (95) to (97), when K=4, I U4 ,I V4 ,I W4 This can be said to accurately reflect the relative anomaly of the current detector to the extent that it satisfies Kirchhoff's current measurement.

[0140] As shown in the lower graph of Figure 15, the predicted relative anomaly (A) increases with the number of corrections performed by the anomaly correction units 519-1 to 519-3. U2C ,A V2C ,A W2C It can be seen that the error with the simulation conditions (etc.) has become smaller.

[0141] The number of additional processing stages N does not need to be fixed; the natural number K can be incremented from "2" by "1" increments, and if any of the convergence conditions QA, QB, or QC listed below are met during this process, the natural number K at that point can be set as the number of additional processing stages N, and the calculation can be terminated.

[0142] • Convergence condition QA: Predicted relative anomaly A calculated by the anomaly correction unit 519-K UKC ,A VKC ,A WKC Then, the predicted relative anomaly A is calculated by the preceding anomaly correction unit 519-(K-1). U(K-1)C ,A V(K-1)C ,A W(K-1)CWhen the difference between each element in the process falls below a predetermined anomaly deviation threshold (e.g., 1%), the current K is set to the number of additional processing stages N, and the calculation is terminated.

[0143] • Convergence condition QB: Anomaly score estimate A calculated by the anomaly score calculation unit 518-K UK ,A VK ,A WK When the sum of the values ​​falls below a predetermined threshold for the estimated anomaly (e.g., 1%) that is close to "0", the calculation is terminated, with the current K being the number of additional processing stages N.

[0144] • Convergence condition QC: Current estimate value I output by current estimation unit 517-K UK ,I VK ,I WK The sum of the input sum I in the abnormality calculation unit 518-K. I0 The amplitude of the current estimate I UK ,I VK ,I WK When the maximum amplitude falls below a predetermined amplitude threshold (e.g., 1%), the current K is set to the number of additional processing stages N, and the calculation is terminated.

[0145] [Fourth Embodiment] Figure 16 shows an example of the configuration of the power converter 101 according to the fourth embodiment. In the following description, parts corresponding to parts of the other embodiments described above will be denoted by the same reference numerals, and their descriptions may be omitted. In Figure 16, the power converter 101 has the same elements as the power converter 100 in the first embodiment (see Figure 2), and further includes a converter-side output estimator 53a (output estimator) and an inverter-side output estimator 53b (output estimator).

[0146] As described above, the converter-side abnormality determination unit 51a determines the current detection value I R ,I S ,I T Based on this, it is determined whether or not an abnormality has occurred in any of the current detectors 14, 15, or 16. Similarly, the inverter-side abnormality determination unit 51b determines whether or not an abnormality has occurred in the current detection value I U ,I V ,IW Based on this, it is determined whether or not an abnormality has occurred in any of the current detectors 24, 25, or 26.

[0147] The converter-side output estimator 53a determines the true current values ​​I of the R-phase, S-phase, and T-phase based on the determination result of the converter-side abnormality determination unit 51a. RT ,I ST ,I TT This is an estimation. Similarly, the inverter-side output estimator 53b estimates the true current values ​​I of the U-phase, V-phase, and W-phase based on the determination result of the inverter-side abnormality determination unit 51b. UT ,I VT ,I WT This is an estimate.

[0148] Figure 17 is a block diagram of the converter-side output estimator 53a and the inverter-side output estimator 53b. Figure 17 shows a scenario where an abnormality occurs in the T-phase current detector 16 and the W-phase current detector 26. Specifically, Figure 17 shows the relationship between the converter-side abnormality determination unit 51a and the converter-side output estimator 53a, as well as the relationship between the inverter-side abnormality determination unit 51b and the inverter-side output estimator 53b in that case. The converter-side abnormality determination unit 51a indicates that the T-phase current detector 16 is abnormal. T Output error information.

[0149] The converter-side output estimator 53a is I T If abnormal information is entered, the current detection value of the R phase I R and the current detection value I of the S phase S By subtracting the sum of these values ​​from "0", the estimated current value of the T phase I is obtained. TH The converter-side output estimator 53a then calculates the calculated T-phase current estimate I. TH This is input to the selection unit 53a1 of the converter-side output estimator 53a.

[0150] The selection unit 53a1 has a current detection value I for the T phase. T And the estimated current value I of the T phase TH The following was entered: TIf abnormal information is entered, the estimated current value of the T phase I TH Select and output the estimated current I of the T phase. TH If no input is provided, the current detection value I of the T phase will be used. T Outputs.

[0151] Then, the converter-side output estimator 53a is I T If abnormal information is input, the current detection values ​​I of the R phase and S phase will be as shown in Figure 17. R ,I S and estimated current I of the T phase TH This is output to the converter control unit 41a. On the other hand, I T If no abnormal information is input, the converter-side output estimator 53a will determine the current detection value I R ,I S ,I T The output is sent to the converter control device 5.

[0152] With this configuration, even if there is a malfunction in the T-phase current detector 16, the T-phase current detection value I T Instead, an appropriate T-phase current estimate I TH It can output the current detection values ​​I of the R phase and S phase that are output. R ,I S and estimated current I of the T phase TH Using this, for example, a "stopgap operation" (details to be described later) can be performed to keep the power converter 101 running continuously until the next periodic inspection.

[0153] Furthermore, the converter-side output estimator 53a performs the same processing as described above even if there is an abnormality in the R-phase current detector 14 or the S-phase current detector 15. That is, the converter-side output estimator 53a calculates the R-phase current detection value I R Instead, a more appropriate R-phase current estimate I RH Apply or the estimated current value of the S phase I SH Instead, a more appropriate S-phase current estimate I SH Apply this.

[0154] Furthermore, the inverter-side output estimator 53b is configured in the same way as the converter-side output estimator 53a. That is, the inverter-side output estimator 53b can be configured by replacing the R phase, S phase, and T phase with the U phase, V phase, and W phase, respectively, as described in the explanation for the converter-side output estimator 53a. The inverter-side output estimator 53b uses the current detection values ​​I of the current detectors 24, 25, and 26 corresponding to the U phase, V phase, and W phase. U ,I V ,I W If an abnormality occurs in any one of the phases, the current estimate for that phase is calculated based on the other two phases. The method for calculating the current estimate for that phase is the same as that for the converter-side output estimator 53a.

[0155] In other words, the inverter-side output estimator 53b uses the current detection values ​​I of the U-phase and V-phase detected by the current detectors 24 and 25. U ,I V By subtracting the sum of these values ​​from "0", the estimated current value of the W phase I is obtained. WH The following can be calculated. The selection unit 53b1 is I W If abnormal information is input, the estimated current value of the W phase I WH Select and output, I W If no abnormal information is entered, the current detection value I W Select and output.

[0156] As described above, with the power converter 101 according to this embodiment, if an abnormality is detected in any of the current detectors 14, 15, 16, 24, 25, or 26, an estimated value is calculated based on the current detection values ​​of the other current detectors to replace the current detection value that would be obtained if the abnormal current detector were functioning correctly. With this configuration, the operation of the power converter 101 can be continued without replacing the abnormal current detector. For example, the load device 2 can be operated continuously for a predetermined period until the next periodic inspection. This method of operation is called "stopgap operation." By performing this "stopgap operation," it is possible to avoid "unplanned shutdowns" of the power converter 101 due to abnormalities in the current detectors.

[0157] [Effects of the Embodiment] As described above, according to the embodiment described above, the abnormality determination device 51 determines the current detection value I of multiple phases detected by the current detectors 24 to 26. U ,I V ,I W Based on this, the calculated original anomaly value A represents the degree of anomaly of each of the multiple current detectors 24-26. U0 ,A V0 ,A W0 The original anomaly calculation unit 516 generates the original anomaly score A, and the original anomaly score calculation value A U0 ,A V0 ,A W0 And, the current detection value I of multiple phases U ,I V ,I W Based on this, the first current estimate for multiple phases (I U1 ,I V1 ,I W1 A first current estimation unit (517-1) calculates the first current estimate value (I) of multiple phases. U1 ,I V1 ,I W1 Based on this, a first anomaly degree estimate (A) represents the degree of anomaly of each of the multiple current detectors 24-26. U1 ,A V1 ,A W1 A first anomaly calculation unit (518-1) generates the original anomaly calculation value A U0 ,A V0 ,A W0 And the first anomaly estimate (A U1 ,A V1 ,A W1 Based on this, a first predicted anomaly score (A) is calculated to represent the degree of anomaly of each of the multiple current detectors 24-26. U1C ,A V1C ,A W1C The system includes a first abnormality correction unit (519-1) that generates a current detector. This allows for the proper detection of abnormalities in the current detector, especially when an imbalance occurs in the load device 2.

[0158] Furthermore, the original abnormality calculation unit 516 includes an abnormality calculation processing unit 511, and the abnormality calculation processing unit 511 calculates the input current value I of multiple phases. UX ,I VX ,I WX The first summation value (II0 A first addition unit (5111) calculates the first sum (I I0 ) and each input current value I UX ,I VX ,I WX The first product is the product of (D U ,D V ,D W A first multiplication unit (5112U, 5112V, 5112W) calculates the product of multiple phases for each of the multiple phases (D U ,D V ,D W The first filter result (F U ,F V ,F W A first filter (5113U, 5113V, 5113W) that outputs ), and the input current value I for each combination of two different phases. UX ,I VX ,I WX The second product is the product of (I VX I WX ,I WX I UX ,I UX I VX A second multiplication unit (5114CW, 5114CU, 5114CV) calculates each of the following, and a second product (I V I W ,I W I U ,I U I V The second summation value (SK) is the sum of the two values. I A second addition unit (5115C) calculates the second sum (SK I The second filtered result (K I A second filter (5116C) outputs ) and each input current value I UX ,I VX ,I WX The squared value of I UX 2 ,I VX 2 ,I WX 2 A third multiplication unit (5114U, 5114V, 5114W) calculates for each phase, and multiple squared values ​​I UX2 ,I VX 2 ,I WX 2 The third summation value (SH) is the sum of the three. I A third addition unit (5115) calculates the third sum (SH I The third filtered result (H I A third filter (5116) outputs ) and the result of the first filter (F U ,F V ,F W ) and the second filter result (H I ) and the result of the third filter (K I Based on this, anomaly calculation result A corresponding to multiple current detectors 24-26 UX ,A VX ,A WX The system includes a calculation unit 5117 that calculates the original abnormality calculation unit 516, which calculates the input current value I of multiple phases. UX ,I VX ,I WX Current detection value I U ,I V ,I W Apply this and calculate the anomaly score A UX ,A VX ,A WX Original abnormality calculation value A U0 ,A V0 ,A W0 Outputting it as such is even preferable.

[0159] This results in the first filter result (F U ,F V ,F W ) and the second filter result (H I ) and the result of the third filter (K I Based on ) and , a more appropriate anomaly calculation result A UX ,A VX ,A WX , in other words, the original abnormality calculation value A U0 ,A V0 ,A W0 It can be calculated.

[0160] Furthermore, the first abnormality calculation unit (518-1) includes an abnormality calculation processing unit 511, and the input current value of multiple phases I UX ,I VX ,I WX The first current estimate (I U1 ,I V1 ,I W1 Apply ) and calculate the anomaly score A UX ,A VX ,A WX The first anomaly estimate (A U1 ,A V1 ,A W1 It is even more preferable to output it as ). This allows for a more appropriate first anomaly estimate (A U1 ,A V1 ,A W1 It can output (this).

[0161] Furthermore, the calculation unit 5117 calculates multiple abnormality scores A UX ,A VX ,A WX It is even preferable to set the sum to "0". This results in a more appropriate abnormality calculation result A UX ,A VX ,A WX It can output.

[0162] Also, the first predicted anomaly (A U1C ,A V1C ,A W1C It is even more preferable to further include an abnormality determination unit 514 that determines whether or not there is an abnormality in any of the current detectors 24 to 26 based on the above. This makes it possible to appropriately determine whether or not there is an abnormality in any of the current detectors 24 to 26.

[0163] Furthermore, the anomaly detection unit 514 determines the first predicted anomaly degree (A) for each of the following: U1C ,A V1C ,A W1C It is even more preferable to have a function that determines that at least one of the multiple current detectors 24 to 26 is abnormal if the largest absolute value of ) exceeds a predetermined abnormality determination threshold (J1). This makes it possible to determine more appropriately whether or not any of the current detectors 24 to 26 is abnormal.

[0164] Furthermore, the anomaly detection unit 514 determines the first predicted anomaly degree (A U1C ,A V1C ,A W1C It is even more preferable to further include a function that determines whether each element of the current detectors 24-26 can be classified into two elements with high similarity and one other element, and if the similarity determination is positive, it determines that only one of the multiple current detectors 24-26 is abnormal, and if the similarity determination is negative, it determines that two or more of the multiple current detectors 24-26 are abnormal. This makes it possible to more appropriately determine whether only one or two or more of the multiple current detectors 24-26 are abnormal.

[0165] Furthermore, the anomaly detection unit 514 determines the first predicted anomaly degree (A) for each of the following: U1C ,A V1C ,A W1C It is even more preferable to further include a function that determines that the current detector 24-26 corresponding to the largest absolute value of ) is abnormal. This allows for more appropriate determination of abnormalities in the current detectors 24-26.

[0166] Furthermore, the number of additional processing stages N is an arbitrary natural number greater than or equal to 2, and the system further comprises a second to the Nth current estimation unit (517-2~N), a second to the Nth abnormality calculation unit (518-2~N), and a second to the Nth abnormality correction unit (519-2~N), where K is an arbitrary natural number such that 2 ≤ K ≤ N, and the Kth current estimation unit (517-K) calculates the current detection value I of multiple phases. U ,I V ,I W And the predicted relative anomaly of the (K-1) order (A U(K-1)C ,A V(K-1)C ,A W(K-1)C Based on this, the estimated current value of the Kth phase of multiple phases (I UK ,I VK ,I WK The abnormality calculation unit (518-K) calculates the current estimate value (I) of the Kth phase, and the abnormality calculation unit (518-K) calculates the current estimate value (I) of the Kth phase for multiple phases. UK ,I VK ,I WK Based on this, the Kth anomaly estimate (A) represents the degree of anomaly of each of the multiple current detectors 24-26. UK ,AVK ,A WK The Kth abnormality correction unit (519-K) generates the original abnormality calculation value A U0 ,A V0 ,A W0 And the first to Kth anomaly estimates (A U1 ~A UK ,A V1 ~A VK ,A W1 ~A WK Based on this, the Kth predicted anomaly score (A) represents the degree of anomaly of each of the multiple current detectors 24-26. UKC ,A VKC ,A WKC It is even more preferable that it generates the Kth predicted anomaly (A) over multiple stages. UKC ,A VKC ,A WKC Since it is possible to calculate ( ), abnormalities in current detectors 24-26 can be determined more accurately.

[0167] Also, the anomaly score estimate for the Kth (A UK ,A VK ,A WK It is even more preferable to further include a function that sets the current natural number K to the number of additional processing stages N when the sum of each element of ) falls below a predetermined threshold for the total estimated anomaly value. This makes the anomaly value of the Kth anomaly value (A UK ,A VK ,A WK Based on this, an appropriate number of additional processing stages N can be determined, thereby shortening the calculation speed.

[0168] Also, the estimated current value of the Kth (I UK ,I VK ,I WK It is even more preferable to further include a function that sets the current natural number K to the number of additional processing stages N when the sum of ) falls below a predetermined amplitude threshold (e.g., 1%). This makes the current estimate of the Kth (I UK ,I VK ,I WK Based on this, an appropriate number of additional processing stages N can be determined, thereby shortening the calculation speed.

[0169] Also, multiple current detection values ​​IU ,I V ,I W If it is determined that an abnormality has occurred in one of the phases, the current detection value I of the other two phases will be measured. U ,I V ,I W Based on this, the current detection value I was determined to be abnormal. U ,I V ,I W It is even more preferable to further include output estimators (53a, 53b) that output estimated values ​​of I. U ,I V ,I W Even if an abnormality occurs in one of the phases, it is still possible to output an appropriate estimated value.

[0170] Furthermore, if the abnormality determination unit 514 determines that an abnormality has occurred in any of the current detectors 24-26, it is preferable that the system further includes an information display unit (52) that presents abnormality information identifying the current detector 24-26 that was determined to be abnormal. The abnormality determination unit 514 is even more preferably equipped with a function that predicts the period until a predetermined abnormal state occurs in the current detectors 24-26 based on the history of the degree of abnormality of the current detectors 24-26 over multiple occasions, and displays the predicted period to the information display unit (52). This makes it possible to predict when an abnormality will occur in the current detectors 24-26, allowing for the formulation of an appropriate maintenance plan, and enabling the user to easily recognize the current detector 24-26 that has been determined to be abnormal.

[0171] [Differentiation] The present invention is not limited to the embodiments described above, and various modifications are possible. The embodiments described above are illustrative examples provided to facilitate understanding of the present invention, and are not necessarily limited to those comprising all the described configurations. Furthermore, it is possible to replace parts of the configuration of one embodiment with those of another embodiment, and to add configurations from other embodiments to the configuration of one embodiment. It is also possible to delete parts of the configuration of each embodiment, or to add or replace other configurations. In addition, the control lines and information lines shown in the figures are those considered necessary for explanation, and do not necessarily represent all control lines and information lines required in the product. In practice, it can be assumed that almost all configurations are interconnected. Possible modifications to the above embodiments are as follows, for example.

[0172] (1) In each of the above embodiments, the presence or absence of abnormalities in the current detectors 14, 15, 16, 24, 25, and 26 in the power conversion unit 3 interposed between the AC power supply 1 and the load device 2 was determined. However, the present invention is not limited to the above configuration, and for example, an AC converter (e.g., a transformer) that converts AC to AC voltage may be provided between the AC power supply 1 and the AC / DC converter 100a. Similarly, an AC converter (e.g., a transformer) that converts AC to AC voltage may be provided between the DC / AC converter 100b and the load device 2. The present invention can also be applied to determining abnormalities in current detectors arranged in all phases (e.g., 3 phases) between the AC power supply 1 and the power conversion unit 3, and between the power conversion unit 3 and the load device 2, in the above various configurations.

[0173] (2) Since the hardware of the anomaly detection device 51 in the above embodiment can be implemented by a general-purpose computer, the programs that execute the processes corresponding to each block diagram and flowchart described above, and other various processes described above, may be stored in a storage medium (a computer-readable recording medium on which the program is recorded) or distributed via a transmission line.

[0174] (3) In the above embodiment, the processes corresponding to each block diagram and flowchart, and the programs that execute the various processes described above, were described as software processes using programs, but some or all of them may be replaced with hardware processes using ASICs (Application Specific Integrated Circuits) or FPGAs (Field Programmable Gate Arrays), etc.

[0175] (4) The various processes performed in the above embodiment may be performed by a server computer via a network (not shown), and the various data stored in the above embodiment may also be stored on the server computer. [Explanation of Symbols]

[0176] 1 AC power supply 2 Load device 3 Power Conversion Unit 14, 15, 16, 24, 25, 26 Current detectors 51 Abnormality detector 52 Display (information presentation section) 53a Converter-side output estimator (output estimator) 53b Inverter-side output estimator (output estimator) 100,101 Power converter 511 Anomaly Score Calculation Processing Unit 514 Abnormality judgment section 516 Original abnormality degree calculation section (original abnormality degree calculation process) 517-1 Current Estimation Unit (First Current Estimation Unit, First Current Estimation Process) 517-K Current Estimation Unit (Kth Current Estimation Unit) 518-1 Anomaly Score Calculation Unit (First Anomaly Score Calculation Unit, First Anomaly Score Calculation Process) 518-K Anomaly Score Calculation Unit (Kth Anomaly Score Calculation Unit) 519-1 Anomaly Severity Correction Unit (First Anomaly Severity Correction Unit, First Anomaly Severity Correction Process) 519-K Anomaly Score Correction Unit (Kth Anomaly Score Correction Unit) 5111 Adder (First Adding Unit) 5112U, 5112V, 5112W Multiplier (First Multiplier Section) 5113U, 5113V, 5113W filters (first filter) 5114U, 5114V, 5114W Multiplier (Third Multiplier Unit) 5114CW, 5114CU, 5114CV Multiplier (Second Multiplier Section) 5115 Adder (Third Adding Unit) 5115C Adder (Second Adding Section) 5116 Filter (Third filter) 5116C filter (second filter) 5117 Arithmetic unit J1 Predetermined value (abnormality detection threshold) D U ,D V ,D W Product (first product) F U ,F V ,F W DC component (first filter result) H I DC component (third filter result) K I DC component (second filter result) A U0 ,A V0 ,A W0 Original abnormality calculation value A U1 ,A V1 ,A W1 Anomaly Score Estimate (First Anomaly Score Estimate) A UK ,A VK ,A WK Anomaly severity estimate (Kth anomaly severity estimate) A UX ,A VX ,A WX Abnormality calculation results A U1C ,A V1C ,A W1C Predicted relative anomaly (first predicted anomaly) A UKC ,A VKC ,A WKCPredicted relative anomaly (predicted anomaly of the Kth order) I U ,I V ,I W Current detection value I I0 Input sum (first sum) I U1 ,I V1 ,I W1 Current estimate (first current estimate) I UK ,I VK ,I WK Current estimate (Current estimate for the Kth term) I UX ,I VX ,I WX Input current value I V I W ,I W I U ,I U I V Multiplication result (second product) I UX 2 ,I VX 2 ,I WX 2 squared value SK I Total value (second sum value) SH I Total value (third sum)

Claims

1. A power conversion device installed between an AC power source and a load device, Multiple current detectors for detecting multi-phase AC currents flowing between the AC power source and the power converter, or between the power converter and the load device, The system includes an abnormality determination device that determines abnormalities in the current detector, The aforementioned anomaly detection device is A fundamental abnormality calculation unit generates a fundamental abnormality calculation value representing the degree of abnormality of each of the multiple current detectors based on the current detection values ​​of multiple phases detected by the current detectors, A first current estimation unit calculates a first current estimate for multiple phases based on the original abnormality calculation value and the current detection values ​​for multiple phases, A first abnormality calculation unit generates a first abnormality estimate that represents the degree of abnormality of each of the multiple current detectors based on the first current estimates of multiple phases, The system includes a first abnormality correction unit that generates a first predicted abnormality value representing the degree of abnormality of each of the plurality of current detectors based on the original abnormality calculation value and the first abnormality estimation value. A power conversion device characterized by the following features.

2. The aforementioned original abnormality calculation unit includes an abnormality calculation processing unit, The abnormality degree calculation processing unit, A first summation unit that calculates a first summation value which is the sum of the input current values ​​of multiple phases, A first multiplication unit calculates a first product, which is the product of the first sum value and each of the input current values, for each of the multiple phases, A first filter that outputs a first filter result which is the result of performing a filter operation on each of the multiple first products, A second multiplication unit calculates a second product, which is the product of the input current values ​​for each combination of two different phases, A second adder that calculates a second sum value which is the sum of multiple second products, A second filter that outputs a second filtered result, which is the result of applying a filter to the second summation value, A third multiplication unit that calculates the square of each of the aforementioned input current values ​​for each phase, A third addition unit that calculates a third sum value which is the sum of the multiple squared values, A third filter that outputs a third filtered result, which is the result of applying a filter to the aforementioned third summation value, The system comprises a calculation unit that calculates an abnormality calculation result corresponding to a plurality of current detectors based on the first filter result, the second filter result, and the third filter result, The original abnormality calculation unit applies the current detection value as the input current value for multiple phases and outputs the abnormality calculation result as the original abnormality calculation value. The power conversion device according to feature 1.

3. The first abnormality calculation unit includes the abnormality calculation processing unit, which applies the first current estimate as the input current value for multiple phases and outputs the abnormality calculation result as the first abnormality estimate. The power conversion device according to feature 2.

4. The calculation unit sets the sum of the multiple abnormality calculation results to "0". The power conversion device according to feature 3.

5. The system further includes an abnormality determination unit that determines whether or not there is an abnormality in any of the current detectors based on the first predicted abnormality level. The power conversion device according to feature 1.

6. The abnormality determination unit includes a function that determines that at least one of the plurality of current detectors is abnormal when the largest absolute value among the first predicted abnormality levels exceeds a predetermined abnormality determination threshold. The power conversion device according to feature 5.

7. The anomaly determination unit further includes a function to determine whether each element of the first predicted anomaly score can be classified into two elements with high similarity and one other element, and if the result of the similarity determination is positive, it determines that only one of the multiple current detectors is anomaly, and if the result of the similarity determination is negative, it determines that two or more of the multiple current detectors are anomaly. The power conversion device according to feature 6.

8. The abnormality determination unit further includes a function to determine that the current detector corresponding to the largest absolute value among the first predicted abnormality levels is abnormal. The power conversion device according to feature 7.

9. The number of additional processing stages N is defined as any natural number of 2 or more, and the second to Nth current estimation units are configured as follows: A second to Nth abnormality calculation unit, It further comprises a second to Nth abnormality correction unit, Let K be any natural number such that 2 ≤ K ≤ N. The current estimation unit for the Kth phase calculates the estimated current value for the Kth phase of multiple phases based on the current detection values ​​for multiple phases and the predicted relative anomaly of the (K-1)th phase. The K abnormality calculation unit generates an K abnormality estimate that represents the degree of abnormality of each of the multiple current detectors based on the current estimates of the multiple phases of K. The K abnormality correction unit is, Based on the original anomaly calculation value and the first to K anomaly estimation values, a K predicted anomaly score is generated that represents the degree of anomaly of each of the multiple current detectors. The power conversion device according to feature 1.

10. The system further includes a function that sets the current natural number K to the number of additional processing stages N when the sum of each element of the anomaly estimation value K falls below a predetermined threshold for the sum of anomaly estimation values. The power conversion device according to feature 9.

11. The system further includes a function that, when the sum of the estimated current values ​​of K falls below a predetermined amplitude threshold, sets the current natural number K to the number of additional processing stages N. The power conversion device according to feature 9.

12. The system further includes an output estimator that, when it is determined that an abnormality has occurred in one of the multiple current detection values, outputs an estimated value of the current detection value in which the abnormality was determined to have occurred, based on the current detection values ​​of the other two phases. The power conversion device according to feature 1.

13. When the abnormality determination unit determines that an abnormality has occurred in any of the current detectors, the system further includes an information display unit that displays abnormality information identifying the current detector that was determined to have experienced an abnormality. The abnormality detection unit further includes a function to predict the period until a predetermined abnormal state occurs in the current detector based on the history of the degree of abnormality of the current detector over multiple occasions, and to have the information display unit display the predicted period. The power conversion device according to feature 8.

14. A base anomaly calculation unit generates a base anomaly calculation value representing the degree of anomaly of each of the multiple current detectors based on the current detection values ​​of multiple phases detected by the current detectors, A first current estimation unit calculates a first current estimate for multiple phases based on the original abnormality calculation value and the current detection values ​​for multiple phases, A first abnormality calculation unit generates a first abnormality estimate that represents the degree of abnormality of each of the multiple current detectors based on the first current estimates of multiple phases, The system includes a first abnormality correction unit that generates a first predicted abnormality value representing the degree of abnormality of each of the plurality of current detectors based on the original abnormality calculation value and the first abnormality estimation value. An anomaly detection device characterized by the following features.

15. A process for calculating the degree of abnormality of multiple current detectors, which generates a calculated value representing the degree of abnormality of each of the multiple current detectors based on the current detection values ​​of multiple phases detected by the current detectors, A first current estimation process that calculates a first current estimate for multiple phases based on the original abnormality calculation value and the current detection values ​​for multiple phases, A first abnormality calculation process that generates a first abnormality estimate representing the degree of abnormality of each of the multiple current detectors based on the first current estimate of multiple phases, The system includes a first anomaly correction process that generates a first predicted anomaly value representing the degree of anomaly of each of the plurality of current detectors, based on the original anomaly calculation value and the first anomaly estimation value. An abnormality detection method characterized by the following.

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